AeroElectric-Archive.digest.vol-dz

February 03, 2005 - February 16, 2005



      
      >Considered modifications:
      >
      >1.) The essential bus has only 7A fuse (breaker) coming of off battery bus 
      >and going to essential switch. But essential bus totals over 30A. Is this 
      >correct Amp rating?
      
         All circuit protection needs to be adjusted for the final
         design . . . keep in mind that the z-figures describe ARCHITECTURE
         and do not purport to size wires and circuit protection or suggest
         any particular compliment of electrical equipment.
      
         Having said that, you have way too much load on the endurance bus.
         The e-bus is intended to give you a high=reliability power source
         for items needed to get airport of intended destination in sight
         while making fuel aboard and not battery capacity drive the
         ultimate limit to duration of flight.
      
      
      >2.) Should not the essential bus' fuse be a current limiter rated at 
      >ANL-40A; and essential bus' switch rated at 40A as well?
      
         No, if you truly intend to load up the e-bus like this, then
         you need to adapt the e-bus alternate feed to include a
         mini-battery contactor at the battery bus as illustrated
         in:
      
         http://www.aeroelectric.com/Pictures/E-BusFatFeed.gif
      
         Keep in mind also that the normal feedpath diode will
         need to be upsized and heat-sinked . . .
      
      
      >3.) Should there be a current limiter (ANL-40A or other Amp) on line from 
      >main bus (or to avionic contactor - see A. below) to rectifier diode?
      >
      >4.) I feel it might be better to use both input connectors with two wires 
      >(and one from(+)output as you have it) on rectifier diode for essential 
      >bus line to essential bus. Basically, two wires from maim bus (or two 
      >wires from avionic contactor - see A. below) to rectifier diode, and one 
      >from diode to essential bus, this for 50A rating?
      
         Doesn't work that way. You really need to rethink the operational
         philosophy of the e-bus and trim the en route running loads of
         on the bus down to something on the order of 3-5 amps max.
      
      
      >My modifications:
      >
      >A.) I installed the Avionic master contactor (and switch) in series with 
      >the rectifier diode for essential bus.
      >B.) BAT and ALT to be powered with two separate switches.
      
         Pleased don't do this. The management of battery and alternator controls
         has been discussed more than ANY other topic and the discussions are
         not over yet. It's generally agreed that being able to switch the
         battery OFF while still having an alternator on-line is an invitation
         to easily avoidable grief and $time$.
      
      >C.) Will use the conventional key OFF/L/R/BOTH/START switch for magnetos 
      >and starter contactor
      
         Ugh! . . . but it WILL function.
      
      >D.) Will have firewall ground bus (2pcs unit from B&C) then braded wire 
      >(engine side) to ENG. On the other side (cabin side) braded wire to 
      >battery (-) but with one more ground bus mounted in series at the 
      >instrument panel proximity similar to the figure Z-14, basically I will 
      >have 3 ground busses in series.
      
          You should have PLENTY of grounds . . . in fact, this sounds
          like you're making this too complex. What kind of airplane/engine
          combination are we discussing?
      
      
      >E.) Alternator N.D.12V/65A with disconnected internal volt regulator and 
      >will use B&C's LR3 volt reg.
      >F.) I installed current limiter ANL-80A on line (8AWG) from battery 
      >contactor to main bus.
      
         Why?
      
      >G.) For starter contactor I elected the Spruce's #22735 unit due to 
      >mounting/space considerations.
      
         It's about the same size as all the other starter contactors
         and probably will do fine.
      
      
      >Bob you comments on all these pints is very welcome.
      >Regards,
      >Garry
      
         If your endurance loads are truly as large as you've suggested,
         then dual alternators are suggested. My earlier recommendation
         that you join the AeroElectric List to discuss this an other
         issues is important. It appears to me that you're driving off
         onto some tangents based on worries based on mis-conceptions
         or poor science. It doesn't have to be this tough. Get on the
         list where I and others will help you sort all this out. I simply
         don't have the time to do this in a one-on-one environment.
      
         Bob . . .
      
      
      
________________________________________________________________________________
Date: Feb 03, 2005
From: rv-9a-online <rv-9a-online(at)telus.net>
Subject: Re: RV-List: Wig Wag
Bill and Bob, here is yet another method of wiring the wig-wag flashers. Similar to Bill's option 4, it uses 1-3 (SPDT) switches only... and the main lamp connections only go through one switch, which should be slightly more reliable. I know Bob looked at this option in the distant past. http://www3.telus.net/aviation/flying/RV-9A/photos/Electrical/wigwag Complete electrical system schematic is at http://www3.telus.net/aviation/flying/RV-9A/rv-9a Follow the links at the top of the page. Vern Little Bill VonDane wrote: > >I have come up with 4 different ways to do this with my wig-wag unit, which >has the same pinout as 'Lectric Bob's... You can check out my installation >instructions, which contain the wiring diagrams, here: >www.creativair.com/source/_inst/exfla.pdf > >I sell either just the flasher, or kits with switches and connectors: >www.creativair.com > >...or you can source your own parts and roll your own... > >-Bill VonDane >bill(at)vondane.com >RV-8A ~ Colorado Springs >www.rv8a.com > > >----- Original Message ----- >From: "DEAN PSIROPOULOS" <dean.psiropoulos(at)verizon.net> >To: ; >Subject: RV-List: Wig Wag > > >--> RV-List message posted by: "DEAN PSIROPOULOS" > > >Len/listers: > >I have a schematic for this type of flasher, it basically does the same >thing as the wig wag but without all the frills(turn it on and it >alternately flashes your two landing lights, that's all). The design is >very simple and uses basically 4 solid state components that I purchased >through Digi Key for less than 10 dollars! I didn't design the circuit but >the designer is a Lancair builder who published it in one of the electronic >trade magazines. He was more than happy to answer my question about using >100 watt aviation lights with it instead of his 50 watt car halogens (it's >plenty robust to operate at the higher currents needed for the aviation >lights). Since the schematic is public knowledge I'm happy to share it with >anyone who is interested in rolling their own wig wag. Just contact me off >list and I'll email you a scanned version of the schematic and the basic >circuit description. > >Note: you need to have some basic knowledge of reading electronic schematics >to be able to do this, but this is a simple circuit that could even be built >on a radio schack perfboard if you really wanted to save money. Not for HID >lights (thier ballasts don't like being switched on and off that fast and... >if you have these really bright lights chances are you'll be seen, even in >the daytime, if you have them on)! > >Dean Psiropoulos >RV-6A N197DM >Light at the end of the tunnel getting briter. > >-----------------------------------------------Original >message------------------------------------- > > >>Lenleg(at)aol.com wrote: >>RV-List message posted by: Lenleg(at)aol.com >> >> > > > >>Anybody give me the contact info for Bob Haan ... producer of the Wig >>Wag???? >>Thanks !! >> >> > > > >>Len Leggette, RV-8A >>Greensboro, NC N910LL >>315 hrs >> >> > > > > ________________________________________________________________________________
Date: Feb 03, 2005
From: Phil Birkelbach <phil(at)petrasoft.net>
Subject: Re: solid state relays
Do a google search for Solid State H-Bridge, and check out the robot hobby sites. I've found some of these things for other projects and up to 3 Amps is pretty easy and I am sure that you can scale them up to 7 or more amps. It's a pretty simple thing to build an H-bridge out of 4 SSR's. Not cheap but easy. Phil D Fritz wrote: > >Question for the group: anyone know of a source of SS relays that work up to about 7 Amp and work in a SPDT fashion? Does such a beast exist? All I seem to find out there are SSRs that work as SPST. I'm working on a roll your own trim relay deck. > >Thanks, >Dan Fritz > > > >--------------------------------- > > > > ________________________________________________________________________________
Date: Feb 04, 2005
From: Richard Dudley <rhdudley(at)att.net>
Subject: Those Chinese Instruments
FWIW There has been a recent thead on this list concerning instruments manufactured outside the USA. My recent experience might be of interest to some list followers. In preparation for FAA inspection of my RV-6A and IFR certification, I had my altimeter-encoder-transponder combination checked at the local avionics repair station. I purchased the altimeter from Van's and is part number;BG-3B. It carries the brand name of Falcon Gauge,Wultrad, Inc. It is manufactured in China. The testing procedure takes the altimeter to pressure altitudes from -1000 feet to 20000 feet at incriments of 500 feet through 2000 feet, 1000 feet through 4000 feet and 2000 feet through 20000 feet and notes the error at each altitude. The results were zero error through 4000 feet and well within the required tolerances through 20000 feet. The technician who conducted tests commented that he tests about two altimeters every day. He said that this altimeter performed at least as well as the name brands that he tests. Regards, Richard Dudley -6A preparing for final inspection ________________________________________________________________________________
Date: Feb 04, 2005
From: AI Nut <ainut(at)hiwaay.net>
Subject: Re: Those Chinese Instruments
But for how long? And what are indications of increasing inaccuracies, if there is a gradual degradation of the units? Richard Dudley wrote: > >FWIW > >There has been a recent thead on this list concerning instruments >manufactured outside the USA. My recent experience might be of interest >to some list followers. > >In preparation for FAA inspection of my RV-6A and IFR certification, I >had my altimeter-encoder-transponder combination checked at the local >avionics repair station. I purchased the altimeter from Van's and is >part number;BG-3B. It carries the brand name of Falcon Gauge,Wultrad, >Inc. It is manufactured in China. > >The testing procedure takes the altimeter to pressure altitudes from >-1000 feet to 20000 feet at incriments of 500 feet through 2000 feet, >1000 feet through 4000 feet and 2000 feet through 20000 feet and notes >the error at each altitude. The results were zero error through 4000 >feet and well within the required tolerances through 20000 feet. > >The technician who conducted tests commented that he tests about two >altimeters every day. He said that this altimeter performed at least as >well as the name brands that he tests. > >Regards, > >Richard Dudley >-6A preparing for final inspection > > >. > > > ________________________________________________________________________________
Date: Feb 04, 2005
From: Bob <flyboy.bob(at)gmail.com>
Subject: Re: Those Chinese Instruments
That sound like a question that could be applied to any item . . . TSO'd or NOT! IMHO . . . if it's good today, under "normal" service it will probably be good tomorrow?! Regards, Bob > > But for how long? And what are indications of increasing inaccuracies, > if there is a gradual degradation of the units? > > > Richard Dudley wrote: > > > > >FWIW > > > >There has been a recent thead on this list concerning instruments > >manufactured outside the USA. My recent experience might be of interest > >to some list followers. > > > >In preparation for FAA inspection of my RV-6A and IFR certification, I > >had my altimeter-encoder-transponder combination checked at the local > >avionics repair station. I purchased the altimeter from Van's and is > >part number;BG-3B. It carries the brand name of Falcon Gauge,Wultrad, > >Inc. It is manufactured in China. > > > >The testing procedure takes the altimeter to pressure altitudes from > >-1000 feet to 20000 feet at incriments of 500 feet through 2000 feet, > >1000 feet through 4000 feet and 2000 feet through 20000 feet and notes > >the error at each altitude. The results were zero error through 4000 > >feet and well within the required tolerances through 20000 feet. > > > >The technician who conducted tests commented that he tests about two > >altimeters every day. He said that this altimeter performed at least as > >well as the name brands that he tests. > > > >Regards, > > > >Richard Dudley > >-6A preparing for final inspection > > > > > >. > > > > > > > > > -- Thanks, Bob ________________________________________________________________________________
Date: Feb 04, 2005
From: Gilles Thesee <Gilles.Thesee@ac-grenoble.fr>
Subject: Horizon question
Hi Bob and all, This is a question about an AIM electric AI. The Horizon runs as soon as the master is ON. A buddy professional pilot told us that we should cage the gyro before starting the engine. This is supposed to prevent damage to the gyro due to the rapid erection on power up. Is that facts or ..? What is your opinion ? Thanks, Gilles Thesee Grenoble, France MCR 4S Fight tests in progress ________________________________________________________________________________
From: "Ed Anderson" <eanderson(at)carolina.rr.com>
Subject: Re: Those Chinese Instruments
Date: Feb 04, 2005
Personal experience - purchased a Chinese AI and DG, knock-off look-alike of RC Allen. AI never erected past 45 deg first time I ever fired it up - would cost $250 to repair (which was just a little less than what I paid for it). Ditched it and got a real RC Allen and have 260 trouble free hours. The Chinese DG has not actually failed - but it clearly is not up to the standards we are used to. Just about useless - would certainly never rely on it. There may be some good Chinese instruments but these were not them. Ed Anderson ----- Original Message ----- From: "Bob" <flyboy.bob(at)gmail.com> Subject: Re: AeroElectric-List: Those Chinese Instruments > > That sound like a question that could be applied to any item . . . > TSO'd or NOT! > > IMHO . . . if it's good today, under "normal" service it will probably > be good tomorrow?! > > Regards, > Bob > > > > > > But for how long? And what are indications of increasing inaccuracies, > > if there is a gradual degradation of the units? > > > > > > Richard Dudley wrote: > > > > > > > >FWIW > > > > > >There has been a recent thead on this list concerning instruments > > >manufactured outside the USA. My recent experience might be of interest > > >to some list followers. > > > > > >In preparation for FAA inspection of my RV-6A and IFR certification, I > > >had my altimeter-encoder-transponder combination checked at the local > > >avionics repair station. I purchased the altimeter from Van's and is > > >part number;BG-3B. It carries the brand name of Falcon Gauge,Wultrad, > > >Inc. It is manufactured in China. > > > > > >The testing procedure takes the altimeter to pressure altitudes from > > >-1000 feet to 20000 feet at incriments of 500 feet through 2000 feet, > > >1000 feet through 4000 feet and 2000 feet through 20000 feet and notes > > >the error at each altitude. The results were zero error through 4000 > > >feet and well within the required tolerances through 20000 feet. > > > > > >The technician who conducted tests commented that he tests about two > > >altimeters every day. He said that this altimeter performed at least as > > >well as the name brands that he tests. > > > > > >Regards, > > > > > >Richard Dudley > > >-6A preparing for final inspection > > > > > > > > >. > > > > > > > > > > > > > > > > > > -- > Thanks, > Bob > > ________________________________________________________________________________
Date: Feb 04, 2005
From: rd2(at)evenlink.com
Subject: Re: Those Chinese Instruments
Hi Ed, I was wondering - how much does the el. (12V) RC Allen AI draw? Rumen _____________________Original message __________________________ (received from Ed Anderson; Date: 05:57 PM 2/4/2005 -0500) Personal experience - purchased a Chinese AI and DG, knock-off look-alike of RC Allen. AI never erected past 45 deg first time I ever fired it up - would cost $250 to repair (which was just a little less than what I paid for it). Ditched it and got a real RC Allen and have 260 trouble free hours. The Chinese DG has not actually failed - but it clearly is not up to the standards we are used to. Just about useless - would certainly never rely on it. There may be some good Chinese instruments but these were not them. Ed Anderson ________________________________________________________________________________
From: "Ed Anderson" <eanderson(at)carolina.rr.com>
Subject: Re: Those Chinese Instruments
Date: Feb 04, 2005
Sorry, Rumen, I jumped in the thread without realizing it was about Chinese Electric gyros - this was vacuum driven. Ed ----- Original Message ----- From: <rd2(at)evenlink.com> Subject: AeroElectric-List: Re: Those Chinese Instruments > > Hi Ed, > I was wondering - how much does the el. (12V) RC Allen AI draw? > Rumen > > _____________________Original message __________________________ > (received from Ed Anderson; Date: 05:57 PM 2/4/2005 > > > Personal experience - purchased a Chinese AI and DG, knock-off look-alike of > RC Allen. AI never erected past 45 deg first time I ever fired it up - > would cost $250 to repair (which was just a little less than what I paid for > it). Ditched it and got a real RC Allen and have 260 trouble free hours. > The Chinese DG has not actually failed - but it clearly is not up to the > standards we are used to. Just about useless - would certainly never rely on > it. There may be some good Chinese instruments but these were not them. > > > Ed Anderson > > ________________________________________________________________________________
From: "Ron" <rondefly(at)rtriano.com>
Subject: Re: crowbar OVM
Date: Feb 05, 2005
I am putting the crowbar OVM together and digikey shorted me on two items. Are there any substitute's I can use that I can get at radio shack or Fry's. the part are: S6025L and 2N3904. Thanks Ron Triano N4710P http://bld01.ipowerweb.com/contentmanagement/websites/rtrianoc/page8.html ________________________________________________________________________________
From: "Bob" <rpgross(at)bellsouth.net>
Subject: Solid State Trim, Speedbrake Relays and so on...
Date: Feb 05, 2005
I hate to use this list to spam but the thread appears so frequently I thought I'd throw this out. When I built my F1, the need for trim control was obvious so I developed a trim control system using an LMD18200T H-bridge driver chip. Problem is it only handles 3 amps. Fine for Vans type A/C, but inadequate for Lancairs, Glasairs, Velocities etc. Along the way I been producing and selling an improved version of the original Trim Control Module (TCM). Details are on my website link below. Basically, the TCM does many cool tricks including: polling two set of sticks for trim motor commands, prioritizing them; variable speed mode for fast aircraft, runaway trim protection, and it does away with mechanical, failure prone relays. All this $99 and available now I've been slowly developing a high powered version that will easily handle 10 amps. In fact with heat sinking, it will handle a blistering 50 amps. This module, when programmed with variations of processor firmware, will serve as: 1. High power trim control module. 2. Intelligent flap control module. 3. Speedbrake control module 4. Boost pump control module 5. and even a Landing gear control module. It's a lot of stuff, but all of it will share the same proven circuit board and MODFET drive system. The common board design will accept an optional pitot/static pressure transducer which, if opted for, will give true variable speed trim motor operation based on IAS. It will also optionally give the Flap Control Module "overspeed load relief" capability which retracts the flaps for you (if you forget on a Go-Around). Think of this as a life saver. The new CPU also has a multi-channel10 bit A/D converter in it so the module can read flap position, speedbrake position, flap control lever position, speed control lever position, airspeed, fuel pressure (for auto boost pump operation) and on and on. Currently the board is being tested. All is going well. I expect the first version s of the high power TCM to available within 2 months. Followed by the Speedbrake module, the boost pump module, Flap Control module and then the Landing gear control module. Basic operation is like this. Please send me ideas and suggestions to operating modes now as this is the time to be heard. 1. TCM, same operation as current TCM only optional pitot/static users get true variable speed trim. 2, Flap Control Module. Either a selector lever positions the flaps or three buttons marked UP,MID,FULL do. This will also accommodate Infinity grips with the two position up/down switch. Holding the button for more that one second causes flaps to drive full to the limit selected. Pitot/Static versions always have load relief watching them. Flaps won't extend at excessively high speeds, and will retract at excessively high speeds. Aircraft using a "flap selector lever" must install a feedback device on the flap system to report flap position to the FCM. The flaps may be position in any position desired by moving the lever. 3.Speedbrake Control Module. Moving a lever commands the speed brake to move the appropriate amount. An optional throttle switch will cause a "SPPEDBRAKE WARNING" light to illuminate if the speedbrake are extended with the throttle opened beyond a point determined by the builder. Feedback sensor must be installed to speedbrake to report position back to SCM. 4. Boost Pump Control Module: Press the switch.pump on-light on, press again.pump off-light off. Low fuel pressure turns pump on-light on. After fifteen minute of pump operation, switch LED begins to flash reminding pilot to do something. Keep building and keep dreaming.it's worth the wait! Warmest Regards, Bob Gross For the latest F1 Rocket/Synthetic Vision progress, click here... www.F1-RocketBoy.com <http://www.f1-rocketboy.com/> -----Disclaimer--------- The contents of this E-mail (including contents of enclosure/(s) or attachment/(s) if any are privileged & confidential material of Innovative Aviation Systems Inc. or RocketBoy Aircraft Products Inc. and should not be disclosed to, used by, or copied in any manner by anyone other than intended addressee/(s).If this E-mail (including enclosure/(s) or attachment/(s) if any has been received in error, please advise sender immediately and delete it from your system. The views expressed in this E-mail message (including enclosure/(s) or attachment/(s) if any are those of the individual sender. ________________________________________________________________________________
Date: Feb 05, 2005
From: Richard Riley <richard(at)RILEY.NET> so on...
Subject: Re: Solid State Trim, Speedbrake Relays and
so on... I am interested in several of the modules. I have 2 switches on my throttle - one at the closed end, one at the open end. I'd want the speed brake to retract with activation of the "open" throttle switch. I don't want it to retract with high airspeed, I use it at 180 mph. I'm also interested in the gear control. I DON'T want it to allow me to retract the gear unless I'm at 90 mph or above. Also interested in the fuel pump module. However, I'll use it with a SPDT switch - up is ON, down is AUTO. At 10:54 AM 2/5/05, you wrote: > >I hate to use this list to spam but the thread appears so frequently I >thought I'd throw this out. When I built my F1, the need for trim control >was obvious so I developed a trim control system using an LMD18200T H-bridge >driver chip. Problem is it only handles 3 amps. Fine for Vans type A/C, but >inadequate for Lancairs, Glasairs, Velocities etc. > > >Along the way I been producing and selling an improved version of the >original Trim Control Module (TCM). Details are on my website link below. >Basically, the TCM does many cool tricks including: polling two set of >sticks for trim motor commands, prioritizing them; variable speed mode for >fast aircraft, runaway trim protection, and it does away with mechanical, >failure prone relays. All this $99 and available now > > >I've been slowly developing a high powered version that will easily handle >10 amps. In fact with heat sinking, it will handle a blistering 50 amps. >This module, when programmed with variations of processor firmware, will >serve as: > >1. High power trim control module. >2. Intelligent flap control module. >3. Speedbrake control module >4. Boost pump control module >5. and even a Landing gear control module. > > >It's a lot of stuff, but all of it will share the same proven circuit board >and MODFET drive system. The common board design will accept an optional >pitot/static pressure transducer which, if opted for, will give true >variable speed trim motor operation based on IAS. It will also optionally >give the Flap Control Module "overspeed load relief" capability which >retracts the flaps for you (if you forget on a Go-Around). Think of this as >a life saver. > > >The new CPU also has a multi-channel10 bit A/D converter in it so the module >can read flap position, speedbrake position, flap control lever position, >speed control lever position, airspeed, fuel pressure (for auto boost pump >operation) and on and on. > > >Currently the board is being tested. All is going well. I expect the first >version s of the high power TCM to available within 2 months. Followed by >the Speedbrake module, the boost pump module, Flap Control module and then >the Landing gear control module. > > >Basic operation is like this. Please send me ideas and suggestions to >operating modes now as this is the time to be heard. > > >1. TCM, same operation as current TCM only optional pitot/static users >get true variable speed trim. > > > 2, Flap Control Module. Either a selector lever positions the flaps or >three buttons marked UP,MID,FULL do. This will also accommodate Infinity >grips with the two position up/down switch. Holding the button for more that >one second causes flaps to drive full to the limit selected. Pitot/Static >versions always have load relief watching them. Flaps won't extend at >excessively high speeds, and will retract at excessively high speeds. >Aircraft using a "flap selector lever" must install a feedback device on the >flap system to report flap position to the FCM. The flaps may be position in >any position desired by moving the lever. > > >3.Speedbrake Control Module. Moving a lever commands the speed brake to move >the appropriate amount. An optional throttle switch will cause a "SPPEDBRAKE >WARNING" light to illuminate if the speedbrake are extended with the >throttle opened beyond a point determined by the builder. Feedback sensor >must be installed to speedbrake to report position back to SCM. > > > 4. Boost Pump Control Module: Press the switch.pump on-light on, press >again.pump off-light off. Low fuel pressure turns pump on-light on. After >fifteen minute of pump operation, switch LED begins to flash reminding pilot >to do something. > > >Keep building and keep dreaming.it's worth the wait! > > >Warmest Regards, > > >Bob Gross >For the latest F1 Rocket/Synthetic Vision progress, click here... >www.F1-RocketBoy.com <http://www.f1-rocketboy.com/> > > >-----Disclaimer--------- >The contents of this E-mail (including contents of enclosure/(s) or >attachment/(s) if any are privileged & confidential material of Innovative >Aviation Systems Inc. or RocketBoy Aircraft Products Inc. and should not be >disclosed to, used by, or copied in any manner by anyone other than intended >addressee/(s).If this E-mail (including enclosure/(s) or attachment/(s) if >any has been received in error, please advise sender immediately and delete >it from your system. The views expressed in this E-mail message (including >enclosure/(s) or attachment/(s) if any are those of the individual sender. > > ________________________________________________________________________________
Date: Feb 05, 2005
From: Richard Riley <richard(at)RILEY.NET> so on...
Subject: Re: Solid State Trim, Speedbrake Relays and
so on... Sorry, I meant for that to only go to Bob. >I am interested in several of the modules. ________________________________________________________________________________
Date: Feb 05, 2005
From: D Fritz <dfritzj(at)yahoo.com>
Subject: Re: solid state relays
Thanks for all the suggestions. Looks like I have a little studying to do, but it doesn't appear too difficult. Dan --------------------------------- ________________________________________________________________________________
Date: Feb 06, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: Solid State Trim, Speedbrake Relays and so
on... Hi Bob, This is great information. I applaud the efforts of you and other entrepreneurs like you. I also enjoy reading your site, and have learned a lot from it. Please keep up the good work! Best regards, Mickey > I hate to use this list to spam but the thread appears so frequently I > thought I'd throw this out. When I built my F1, the need for trim control > was obvious so I developed a trim control system using an LMD18200T H-bridge > driver chip. Problem is it only handles 3 amps. Fine for Vans type A/C, but > inadequate for Lancairs, Glasairs, Velocities etc. > > ... -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
From: "Wayne Sweet" <w_sweet(at)comcast.net>
Subject: Source question
Date: Feb 06, 2005
Just finished Bob's seminar at Watsonville and discovered I have a NO-NO in my plane (been flying for 14 years though). Forgot to ask Bob for the source for the ANL60/30's; will be re-doing my main power to Z-11/14 configuration and doing the backup battery with a SD-8.. Does someone have a source for these current limiters (silly question, I know)? Oh, and since I don't have a clue what they look like, how are they installed forward on the firewall and still are somewhat protected from the "elements" (heat, various cooling blast tubes)? Thanks. Wayne Try www.SPAMfighter.com for free now! ________________________________________________________________________________
From: "Larry Ford" <psychden(at)sonic.net>
Subject: Re: Solid State Trim, Speedbrake Relays and so on...
Date: Feb 06, 2005
Bob- This sounds like what a lot of builders have been looking for. I'm interested in finding a servo motor with a longer travel than the 1.2" that the Ray Allen T3-12A provides. I could use another .5" as I've run out of travel for the custom captured spring design on my elevator trim system. Anyone have any ideas? Larry Ford Glasair I RG N149LF 266hrs. ________________________________________________________________________________
Subject: Re: Source question
Date: Feb 06, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
Wayne - I have some pictures of the limiters installed on our Z-14. Email me off list if you want them and I'll email them. B&C carries the ANL's and the holders. http://www.bandc.biz/ Cheers, John > Just finished Bob's seminar at Watsonville and discovered I have a NO-NO > in my plane (been flying for 14 years though). Forgot to ask Bob for the > source for the ANL60/30's; ________________________________________________________________________________
From: "Matthew Brandes" <matthew(at)n523rv.com>
Subject: AC vs. DC Switches by Art Bianconi
Date: Feb 07, 2005
Was flipping through the latest Sport Aviation last night and was reading one of the letters to the editor and saw reference to the above article. Worth a read... http://www.eaa.org/benefits/sportaviation/0502_switches.pdf Matthew Brandes, Van's RV-9A (Finish Kit) EAA Chapter 868/91/1329 www.n523rv.com <http://www.n523rv.com/> ________________________________________________________________________________
Date: Feb 07, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: AC vs. DC Switches by Art Bianconi
Hi, This has been discussed... http://www.aeroelectric.com/articles/swtchrat.pdf Mickey > Was flipping through the latest Sport Aviation last night and was reading > one of the letters to the editor and saw reference to the above article. > Worth a read... > > http://www.eaa.org/benefits/sportaviation/0502_switches.pdf > -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
From: "cgalley" <cgalley(at)qcbc.org>
Subject: Re: AC vs. DC Switches by Art Bianconi
Date: Feb 07, 2005
That is a really flawed article. Bob will probably comment as I got a lot of flack when I reprinted it in the Experimenter. It has been printed and re-printed numerous times BUT it doesn't make it accurate. Cy Galley EAA Safety Programs Editor Always looking for ideas and articles for EAA Sport Pilot ----- Original Message ----- From: "Matthew Brandes" <matthew(at)n523rv.com> Subject: AeroElectric-List: AC vs. DC Switches by Art Bianconi > > Was flipping through the latest Sport Aviation last night and was reading > one of the letters to the editor and saw reference to the above article. > Worth a read... > > http://www.eaa.org/benefits/sportaviation/0502_switches.pdf > > > Matthew Brandes, > Van's RV-9A (Finish Kit) > EAA Chapter 868/91/1329 > www.n523rv.com <http://www.n523rv.com/> > > ________________________________________________________________________________
From: George Neal E Capt AU/CCP <Neal.George(at)maxwell.af.mil>
Subject: Solid State Trim, Speedbrake Relays and so
on...
Date: Feb 07, 2005
Larry - Big quarter-scale R/C servos from Futaba or Airtronics with a long arm should have enough torque. Perhillian Designs has a solid-state driver that will work with them. Or you could use the RAC servo to position a lever (straight bellcrank) with a longer arm, trade torque for distance. Neal > I could use another .5" as I've run out of travel for the custom captured spring design on my elevator trim system. Anyone have any ideas? Larry Ford Glasair I RG N149LF 266hrs. < ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Re: Solid State Trim, Speedbrake Relays and so on...
Date: Feb 07, 2005
> > Bob Gross > For the latest F1 Rocket/Synthetic Vision progress, click here... > www.F1-RocketBoy.com <http://www.f1-rocketboy.com/> Great web site Bob! I noticed in your FAQ that you weren't overly happy with the moving map software that you are running. You might want to take a look at www.pocketfms.com They have a PC and an iPAQ version. Good software, good support and... for free! I run it on my iPAQ and am very happy with it. Take care, Hans ________________________________________________________________________________
From: "Jones, Michael" <MJones(at)hatch.ca>
Subject: mag switches
Date: Feb 07, 2005
hi all is see in my aeroelectric book on z-11 generic system that 2-5 switches are used for mag control, in the section under switches pg 11-18 however 2-3 switches are described for use on the mag controls, which is correct or are both correct if using the 2-5 switches i see there is no push button for a start, is this because of the spring loaded 2-5 switches, so what happens at each switch when starting the engine right mag, position 1 off, position 2 ??. spring position 3 ??? left mag, position 1 off, position 2 on, spring position 3 start then back to position 2 on guess what i need is what does off-start/on refer to on the 3 switch position thanx mike murphy rebel NOTICE - This message is the property of HATCH. It may also be confidential and/or privileged. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action with respect to it. If you have received this message in error please notify HATCH immediately via mailto:MailAdmin(at)hatch.ca. ________________________________________________________________________________
From: "Tinne maha" <tinnemaha(at)hotmail.com>
Subject: Measurements
Date: Feb 07, 2005
Bob/List, I would like to measure the current used by my landing/taxi light. The multi-meters I have access to only measure up to 2 amps, but I'm sure my light uses more than that (on the order of 5-10 amps, I believe). Can you tell me where I can get an ammeter that measures more than 2 amps? Is it inadvisable to use the ammeter I will install in my plane? Any help is appreciated. Thanks, Grant ________________________________________________________________________________
Subject: Measurements
Date: Feb 07, 2005
From: "Chuck Jensen" <cjensen(at)dts9000.com>
Poor mans measurement. With your master on, check the amp draw. Turn no landing light and note amp draw. After that, the math is simple....and accurate enough to tell the difference between 2, 5 or 10 amp draw. -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Tinne maha Subject: AeroElectric-List: Measurements Bob/List, I would like to measure the current used by my landing/taxi light. The multi-meters I have access to only measure up to 2 amps, but I'm sure my light uses more than that (on the order of 5-10 amps, I believe). Can you tell me where I can get an ammeter that measures more than 2 amps? Is it inadvisable to use the ammeter I will install in my plane? Any help is appreciated. Thanks, Grant ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Measurements
Date: Feb 08, 2005
Or look at the light bulb of your landing light.... 100 Watt => 100/12 = 8 amps But of course that would be too obvious... Hans > -----Oorspronkelijk bericht----- > Van: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > aeroelectric-list-server(at)matronics.com] Namens Chuck Jensen > Verzonden: maandag 7 februari 2005 19:34 > Aan: aeroelectric-list(at)matronics.com > Onderwerp: RE: AeroElectric-List: Measurements > > > > Poor mans measurement. With your master on, check the amp draw. Turn no > landing light and note amp draw. After that, the math is simple....and > accurate enough to tell the difference between 2, 5 or 10 amp draw. > > -----Original Message----- > From: owner-aeroelectric-list-server(at)matronics.com > [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Tinne > maha > To: aeroelectric-list(at)matronics.com > Subject: AeroElectric-List: Measurements > > > > > Bob/List, > > I would like to measure the current used by my landing/taxi light. The > multi-meters I have access to only measure up to 2 amps, but I'm sure my > light uses more than that (on the order of 5-10 amps, I believe). > > Can you tell me where I can get an ammeter that measures more than 2 amps? > Is it inadvisable to use the ammeter I will install in my plane? > > Any help is appreciated. Thanks, > Grant > > > > > ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Dual Electronic Starting Issues
Date: Feb 08, 2005
Thanks James, Z-14 is a dual alternator dual battery setup. I've got a single alternator, dual battery. The crossfeed feature in Z-14 sounds good though... I'll have a good look... Thanks Hans > -----Oorspronkelijk bericht----- > Van: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > aeroelectric-list-server(at)matronics.com] Namens James E. Clark > Verzonden: woensdag 2 februari 2005 16:59 > Aan: aeroelectric-list(at)matronics.com > Onderwerp: RE: AeroElectric-List: Dual Electronic Starting Issues > > > > Have you considered Z-14? > > I am using it and it **appears** to me to offer more with less complexity > than what you propose. > > James > > > | -----Original Message----- > | From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > | aeroelectric-list-server(at)matronics.com] On Behalf Of Hans Teijgeler > | Sent: Tuesday, February 01, 2005 11:31 AM > | To: aeroelectric-list(at)matronics.com > | Subject: RE: AeroElectric-List: Dual Electronic Starting Issues > | > | > | > | Hi list, > | > | I guess I am one of the 1300 silent ones on this list. Joined fairly > | recently and trying to catch up as much as I can. > | > | Quick introduction: I am working on a Subaru powered Jodel DR1050. It > has > | flown last summer, before I decided to redo the engine and fit an NSI > | rather > | than my own contraption. The first iteration was single strand > everything > | (battery, alternator, computer, ignition), the NSI has a lot of > | redundancy > | built in. > | > | Sanity check please guys? > | > | I've been going over the NSI wiring diagrams and came away impressed by > | the > | complexity of it all. Switches, keyed switches, backup switches that > | overrule other switches. All very neat and dandy, and each of the > systems > | can take over other parts without the systems "downstream" noticing > | anything. > | > | But oh boy, what a lot of complexity. A dozen relays, two dozen diodes, > | switches all over the place, and a dizzified pilot scratching his head > on > | his way down to terra firma with a frozen prop. > | > | Personally, I was thinking more along the following lines: > | > | (Keep it simple) > | > | Battery A feeds engine bus A and EFI pump A > | Battery B feeds engine bus B and EFI pump B > | > | The engine bus will run the computer, ignition, injectors, the lot. All > | except the fuel pumps. > | > | So four switches: EFI/IGN A and B and pump A and B. > | > | NO crossovers between the systems. > | > | This means that in case of a double-failure (and one occuring in each > | system) I am screwed, where the original NSI will likely purr on. I can > | live > | with that. > | > | > | What remains then: > | * The main electrical bus > | * The alternator > | * The starter > | > | The main bus I want to connect to either battery A or B via a toggle > | switch > | (with relay to prevent the switch from going ballistic) > | > | The alternator I wanted to connect to both batteries via a pair of 60 > amp > | diodes and a pair of disconnect-relays (and yes, if I completely > isolate > | battery A from the alternator circuit, I will use battery B to power > that > | relay and vice versa) > | > | The starter would get its main power supply via either one of two > | external > | starter solenoids. The external solenoids and the internal one are to > be > | fed > | by a push (starter) button and a toggle switch to select battery A or > B. > | > | And, coming back to the original subject: I guess it makes sense to > start > | the engine with the computer on one battery and selecting the other > | battery > | for the starter. > | > | Any comments are welcome! > | > | Thanks, > | > | Hans Teijgeler > | www.jodel.com > | PH-MGA, Jodel DR1050, Subaru engine > | > | > | > -----Oorspronkelijk bericht----- > | > Van: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > | > aeroelectric-list-server(at)matronics.com] Namens Duane Zavadil > | > Verzonden: maandag 31 januari 2005 6:02 > | > Aan: aeroelectric-list(at)matronics.com > | > Onderwerp: Re: AeroElectric-List: Dual Electronic Starting Issues > | > > | > > | > > | > That is interesting - maybe with diodes to prevent backfeeding. > | Probably > | > just one more part to break though. When diodes go bad, they go > open! > | > > | > I like Frank's idea of a switchable voltmeter to check the backup > | battery > | > and Georges point about nothing between the battterys and the unit > | other > | > than a switch. I think that is the way it is now. I'll take a look > at > | > the schematics that George forwarded. Thanks for all the help! > | > ---------- Original Message ---------------------------------- > | > From: TimRhod(at)aol.com > | > Date: Sun, 30 Jan 2005 17:30:15 EST > | > > | > > > | > >Does it make any sense in a duel battery duel electronic ignition > | setup > | > to > | > >run two wires from each battery to each electronic ignition.? > | > > > | > > > | > > | > > | > Sent via the WebMail system at hometownaccess.net > | > > | > > | > > | > > | > > | > > | > > | > > | > | > | > | > | > > > > > ________________________________________________________________________________
From: "Jones, Michael" <MJones(at)hatch.ca>
Subject: switch guards
Date: Feb 08, 2005
hi all found web site with some really good looking toggle switch guards, for any one who wants to spruce up a boring looking panel, they have reproductions of guards from space shuttle and x-15 rocket plane panels, not that expensive either http://periheliondesign.com/ mike#007 <> <> NOTICE - This message is the property of HATCH. It may also be confidential and/or privileged. If you are not the intended recipient of this message you are hereby notified that you must not disseminate, copy or take any action with respect to it. If you have received this message in error please notify HATCH immediately via mailto:MailAdmin(at)hatch.ca. ________________________________________________________________________________
Date: Feb 08, 2005
From: <chaztuna(at)adelphia.net>
Subject: Re: switch guards
I'm using the Space Shuttle replica switch guards in my 8A. They are very nice. The have the "tang" which keys the toggle switch, machined into them. By using a 1 1/16" spacing, you can install a guard on every other hole and the spacing will be perfect. A very nice product. Charlie Kuss ---- "Jones wrote: > > hi all > > found web site with some really good looking toggle switch guards, for any > one who wants to spruce up a boring looking panel, they have reproductions > of guards from space shuttle and x-15 rocket plane panels, not that > expensive either > > http://periheliondesign.com/ > > mike#007 <> <> > > > NOTICE - This message is the property of HATCH. It may also be > confidential and/or privileged. If you are not the intended recipient > of this message you are hereby notified that you must not disseminate, > copy or take any action with respect to it. > > If you have received this message in error please notify > HATCH immediately via mailto:MailAdmin(at)hatch.ca. > > > > > > ________________________________________________________________________________
Date: Feb 08, 2005
From: Christopher Stone <rv8iator(at)earthlink.net>
Subject: Re: Measurements
Tinne... power(watts)=Current(amps) x Voltage(volts) a bit o' algebra yields amps=watts\volts so divide the rated lamp wattage by 14 for a 14 volt system and you will get steady state current in amps. Chris Stone slowest RV builder on the planet RV-8 wings (still) Bob/List, I would like to measure the current used by my landing/taxi light. The multi-meters I have access to only measure up to 2 amps, but I'm sure my light uses more than that (on the order of 5-10 amps, I believe). Can you tell me where I can get an ammeter that measures more than 2 amps? Is it inadvisable to use the ammeter I will install in my plane? Any help is appreciated. Thanks, Grant ________________________________________________________________________________
Date: Feb 08, 2005
From: <gmcjetpilot(at)yahoo.com>
Subject: Coax and BNC connector signal Loss?
Looking for some opinions from avionics/electronic experts in regards to coax runs, in particular for a transponder, but I assume it applies to com radios as well. How much loss is there per foot of coax (Rx/Tx)? (RG400, RG58) How much signal loss does each BNC connection represent? Can you reuse a tray coax connector,e.g. de-solder old coax to install new coax? (currently my used tray came with a short coax "service lead" with a BNC connector. I don't really need it, but hate to buy another fitting which I understand is expensive.) Last, if I use a bulkhead fitting to go pass the coax thru the firewall, should I use a regular fitting or an isolated one? (I am going to mount my transponder antenna fwd of firewall.) The reason I ask is my transponder to antenna coax is starting to looking like a jigsaw puzzle with several short coax runs and connectors. I can eliminate some of the individual runs and connectors with extra effort if needed. Thanks George --------------------------------- ________________________________________________________________________________
Date: Feb 08, 2005
From: <gmcjetpilot(at)yahoo.com>
Subject: Re: ELCHEAPWIRE switch.
"Eric M. Jones" wrote: >Saw the below listed switch on ELCHEAPWIRE's web site, and wonder if it >is suitable for DC. > >http://www.elwirecheap.com/glowingstuff/sirosw.html > >They make outrageous claims for current capability (obviously haven't >read Aerolectric's basics on electricity). I have had dealing with el-chepo wire and was very unsatisfied. I bought there dual EL light. the first one came, DOA. It was agreed to return for refund. I end up getting another set, this time the sticky backed tape was peeled off the bake and the adhesive was contaminated and ruined. I would not do business with them again. Cheers George --------------------------------- ________________________________________________________________________________
From: "Ron Triano" <rondefly(at)rtriano.com>
Subject: Crowbar OVM
Date: Feb 08, 2005
I am putting the crowbar OVM together and digikey shorted me on two items. Are there any substitute's I can use that I can get at radio shack or Fry's. the part are: S6025L and 2N3904. Thanks Ron Triano N4710P ________________________________________________________________________________
From: "Ron Triano" <rondefly(at)rtriano.com>
Subject: test
Date: Feb 08, 2005
________________________________________________________________________________
From: BobsV35B(at)aol.com
Date: Feb 08, 2005
Subject: Re: test
In a message dated 2/8/2005 10:30:51 P.M. Central Standard Time, rondefly(at)rtriano.com writes: AeroElectric-List message posted by: "Ron Triano" Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Coax and BNC connector signal Loss?
> >Looking for some opinions from avionics/electronic experts in >regards to coax runs, in particular for a transponder, but I assume >it applies to com radios as well. > >How much loss is there per foot of coax (Rx/Tx)? (RG400, RG58) Not enough to be concerned about for lengths usually found on SE light airplanes but here's the data: http://www.aeroelectric.com/articles/coaxloss.pdf >How much signal loss does each BNC connection represent? Very small and frequency dependent. >Can you reuse a tray coax connector,e.g. de-solder old coax to install new >coax? (currently my used tray came with a short coax "service lead" with a >BNC connector. I don't really need it, but hate to buy another fitting >which I understand is expensive.) Clean it up and re-use it. >Last, if I use a bulkhead fitting to go pass the coax thru the firewall, >should I use a regular fitting or an isolated one? (I am going to mount my >transponder antenna fwd of firewall.) Grounded will be fine. Bob . . . -------------------------------------------------------- < Throughout history, poverty is the normal condition > < of man. Advances which permit this norm to be > < exceeded -- here and there, now and then -- are the > < work of an extremely small minority, frequently > < despised, often condemned, and almost always opposed > < by all right-thinking people. Whenever this tiny > < minority is kept from creating, or (as sometimes > < happens) is driven out of a society, the people > < then slip back into abject poverty. > < > < This is known as "bad luck". > < -Lazarus Long- > <------------------------------------------------------> http://www.aeroelectric.com ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Source question
> >Just finished Bob's seminar at Watsonville and discovered I have a NO-NO >in my plane (been flying for 14 years though). Forgot to ask Bob for the >source for the ANL60/30's; will be re-doing my main power to Z-11/14 >configuration and doing the backup battery with a SD-8.. Does someone have >a source for these current limiters (silly question, I know)? Oh, and >since I don't have a clue what they look like, how are they installed >forward on the firewall and still are somewhat protected from the >"elements" (heat, various cooling blast tubes)? >Thanks. >Wayne http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?7X358218#%20c903-1 http://www.bussmann.com/library/bifs/2133.PDF http://www.bussmann.com/library/bifs/2024.PDF Bob . . . ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: crowbar OVM
> >I am putting the crowbar OVM together and digikey shorted me on two items. >Are there any substitute's I can use that I can get at radio shack or Fry's. >the part are: > >S6025L and 2N3904. These parts show in-stock at Digikey in large quantities. Did they charge you for them and not ship or simply deleted them from your order as back-ordered/out-of-stock? If they charged you for them and didn't ship, they'll rectify the error if you give them a call. There are TONS of suitable substitutes but couldn't suggest one without knowing what lines and or numbers Fry's stocks. Bob . . . ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: switch guards
Date: Feb 09, 2005
Thanks Michael. Just what I was looking for. I've ordered four pairs of Hans > -----Oorspronkelijk bericht----- > Van: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > aeroelectric-list-server(at)matronics.com] Namens Jones, Michael > Verzonden: dinsdag 8 februari 2005 14:30 > Aan: AeroElectric-List Digest Server (E-mail) > Onderwerp: AeroElectric-List: switch guards > > > > hi all > > found web site with some really good looking toggle switch guards, for any > one who wants to spruce up a boring looking panel, they have reproductions > of guards from space shuttle and x-15 rocket plane panels, not that > expensive either > > http://periheliondesign.com/ > > mike#007 <> <> > > > NOTICE - This message is the property of HATCH. It may also be > confidential and/or privileged. If you are not the intended recipient > of this message you are hereby notified that you must not disseminate, > copy or take any action with respect to it. > > If you have received this message in error please notify > HATCH immediately via mailto:MailAdmin(at)hatch.ca. > > > > > ________________________________________________________________________________
From: owner-aeroelectric-list-server(at)matronics.com
Subject: Aeroelectrci - two battery, two alternator system (
Z-11)
Date: Feb 09, 2005
This is really a question for Bob. But here goes to the list anyway. Being new to building a plane and to electrical matters, I read Bob's book cover to cover twice and was sold on the idea of fitting my RV8 with a two alternator, two battery system (two years for each battery). System seems good and it one main advantage: two level redundancy. But a nagging feeling keeps coming back. In an attempt at applying the KISS principle (for those who might not be aware aka 'keep it simple, stupid'), I tell myself would I not be better off with a very simple one battery, one alternator setup? Am I not with all those extra wires and switches and other equipment offsetting the redundancy advantage with a higher risk at having a complexity related failure? That's it - if Bob or anyone else would care to comment? One last thing - I know it is my airplane and that I should do whatever seems best for me - but I would appreciate some enlightened intelligent comments. Regards, Michle Delsol RV8 - Wings going on to the fuselage ________________________________________________________________________________
Date: Feb 09, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: Aeroelectrci - two battery, two alternator
system ( Z-11) Hi Michle, What kind of flying do you plan for the airplane? What kind of stuff will you install? Is the airplane electrically dependent? (no mags?) If you have mags, and plan on daytime VFR, then dual batteries and dual alternators seems to be overkill. If you plan to fly it over the Atlantic with an electrically dependent engine, then 2+2 is probably a good idea. Mickey owner-aeroelectric-list-server(at)matronics.com wrote: > > This is really a question for Bob. But here goes to the list anyway. > > Being new to building a plane and to electrical matters, I read Bob's book > cover to cover twice and was sold on the idea of fitting my RV8 with a two > alternator, two battery system (two years for each battery). System seems > good and it one main advantage: two level redundancy. > > But a nagging feeling keeps coming back. In an attempt at applying the KISS > principle (for those who might not be aware aka 'keep it simple, stupid'), I > tell myself would I not be better off with a very simple one battery, one > alternator setup? Am I not with all those extra wires and switches and other > equipment offsetting the redundancy advantage with a higher risk at having a > complexity related failure? > > That's it - if Bob or anyone else would care to comment? > > One last thing - I know it is my airplane and that I should do whatever > seems best for me - but I would appreciate some enlightened intelligent > comments. -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
Date: Feb 09, 2005
From: Charlie Kuss <chaztuna(at)adelphia.net>
Subject: Routing large power cables near radios
Bob & Listers, Does anyone foresee problems by running my main positive (rear) battery cable so that it passes within 4" of the rear of my radio stack? Charlie Kuss ________________________________________________________________________________
Subject: GRT Magnetometer reliance
Date: Feb 09, 2005
From: "Stewart, Michael (ISS Atlanta)" <mstewart(at)iss.net>
Hey guys, I learned something yesterday that is very important to know. I uploaded the recent software into the GRT EFIS. The upload procedure was... frankly... amazing. Insert usb chip into unit, turn knob, and watch. How cool is that? I walked over to my buddy's house who has the dual units installed and updated his. He thought I was very cool. I told him... Its not me, its GRT. A monkey could do it. A very dumb monkey could do it. Anyway, after the upload my attitude did not work and an e-mail to Todd at GRT resulted in the answer. The new version does not show an attitude if the magnetometer is not connected, or fails. The reason being that it needs that data to complete the AHARS solution for attitude. I am still going back and forth with Todd to determine if there is a better way for them to handle an in flight manometer failure than just going TU, but for now this is the behavior you will see in flight. Since the attitude reading requires compass data, I have asked them to look at some other solution like an "ahars unreliable" flag, or countdown to going TU, or something other than instant TU. I do not know what testing led to this new software change but I have to figure that there is some period of time after loss of compass data that it is usable, or partially usable. Also since it is getting ground track from a gps source over a serial data stream, could this not be used as a backup piece of data while the compass is out? I dunno. But I do know "Other" competitors do not rely on external devices to complete the solution for attitude. Thoughts group? Mike Stewart Basement flying the GRT. S8 FWF ________________________________________________________________________________
Subject: GRT Magnetometer reliance
Date: Feb 09, 2005
From: "Chuck Jensen" <cjensen(at)dts9000.com>
Michael, Not showing an attitude indication when the AHARS is disconnected or 'down' on the GRT EFIS may well be the right solution by eliminating a faulty indications. Better to have no attitude indication that is correct, then to have one that's incorrect. The GRT EFIS takes input from both the remote AHARS and GPS, but they provide data for different functions. I would think the AI is primarily dependent on the AHARS, perhaps totally so. If the AHARS goes down, but your GPS is still up, the EFIS will show map data, but no attitude indication. In this case, your AHARS unreliable 'flag' is that there is no attitude indication on the screen. As far as giving an early warning failure flag and getting the benefit of a few remaining minutes of decaying accuracy, I doubt this applies to electric gyros. The old vacuum gyros took a few minutes to spin down, but the electronic ones likely go TU near instantly as there is no mechanical momentum. If you are going to fly IFR, you do have a backup electric or vacuum AI don't you? Chuck -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Stewart, Michael (ISS Atlanta) Subject: AeroElectric-List: GRT Magnetometer reliance Hey guys, I learned something yesterday that is very important to know. I uploaded the recent software into the GRT EFIS. The upload procedure was... frankly... amazing. Insert usb chip into unit, turn knob, and watch. How cool is that? I walked over to my buddy's house who has the dual units installed and updated his. He thought I was very cool. I told him... Its not me, its GRT. A monkey could do it. A very dumb monkey could do it. Anyway, after the upload my attitude did not work and an e-mail to Todd at GRT resulted in the answer. The new version does not show an attitude if the magnetometer is not connected, or fails. The reason being that it needs that data to complete the AHARS solution for attitude. I am still going back and forth with Todd to determine if there is a better way for them to handle an in flight manometer failure than just going TU, but for now this is the behavior you will see in flight. Since the attitude reading requires compass data, I have asked them to look at some other solution like an "ahars unreliable" flag, or countdown to going TU, or something other than instant TU. I do not know what testing led to this new software change but I have to figure that there is some period of time after loss of compass data that it is usable, or partially usable. Also since it is getting ground track from a gps source over a serial data stream, could this not be used as a backup piece of data while the compass is out? I dunno. But I do know "Other" competitors do not rely on external devices to complete the solution for attitude. Thoughts group? Mike Stewart Basement flying the GRT. S8 FWF ________________________________________________________________________________
From: "Stucklen, Frederic W UTPWR" <Fred.Stucklen(at)UTCFuelCells.com>
Subject: Garmin manuals
Date: Feb 09, 2005
Mike & Listers, I'm trying to find an electronic version of the SL10 Installation manual. Mike's list didn't include it, and I haven't been able to find it on the Garmin site. Does anyone have a copy? ====================================== Fred Stucklen RV-6A N926RV phone: (860)727-2393 fax: (860)998-9396 email: fred.stucklen(at)utcfuelcells.com Message: #124797 Subject: more Garmin Appolo Manual <http://www.matronics.com/searching/getmsg_script.cgi?INDEX=155468073?KEYS=m anuals?LISTNAME=RV?HITNUMBER=14?SERIAL=06050918430?SHOWBUTTONS=NO> Downloads Date: Sep 19, 2004 From: "Stewart, Michael (ISS Atlanta)" < mstewart(at)iss.net > Here are some more(added the first few here below) manuals popular found by JB. You will notice by looking at the file names and using the scheme, that you can find just about anything you are looking for. Some file names are not intuitive like GPS165TSODzusRail_PilotsGuide.pdf. Ill try and work on getting the entire directory of everything possible. But for now, this is a really good list. Old and new, popular in junk. Its in there. STC, pilot Guide, Supplemental Flight Manual, Quick Reference Guide, Pilots Guide, Installation Manual, Training Syllabus, all kinds of very useful stuff in there. Just think about how many times you have wanted a manual and could not find it. Especially installation manuals which they seem to keep tight reign on. I ran a job from the office to get all of these, yes every one, so Ill keep them somewhere just in case they disappear. Another fella did that right before they took the appolo site down. I got a file from him like sl40_install_560-0956-03a.pdf. I mean how would you ever figure out that filename? So I hope to have these stashed just in case GArmin gets hit by a bus. <http://www.garmin.com/manuals/> http://www.garmin.com/manuals/ these files below. So if you are looking for a manual, just search this list (ex. Ctl-f 430) and append the filename to the url above and you will have it. Enjoy, Mike Stewart MX20_InstallationManual.pdf SL30Nav_Comm_InstallationManual.pdf ...... ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Routing large power cables near radios
> >Bob & Listers, > Does anyone foresee problems by running my main positive (rear) battery >cable so that it passes within 4" of the rear of my radio stack? >Charlie Kuss it would be a good idea not to do this. It's not a guaranteed formula for noise but if you can get a wider separation (foot or more) it would definitely be a good thing to do. Bob . . . ________________________________________________________________________________
From: "Glaeser, Dennis A" <dennis.glaeser(at)eds.com>
Subject: Re: Aeroelectrci - two battery, two alternator system
Date: Feb 09, 2005
Michel, What is your anticipated mission profile? What engine are you using? The basic decision process I used is this: go down the list of every piece of equipment on your airplane (instruments, electrical power, radios, servos, switches, lights ...) and ask yourself - what will I do when (not if) this fails in-flight? In the case of an alternator, how long can you operate on battery power until something unacceptable happens - like loss of power if you have an electrically dependent engine, or loss of critical instruments or radios if IFR (and don't forget lights if you fly at night). If you want to be able to continue to your destination no matter what, or if you fly where reasonable places to land are few and far between, then either dual alternators or enough battery power to outlast your fuel is in order. If you have an engine that doesn't require electricity, having enough battery to run radios and instruments for a long time is not tough to do. If your engine requires juice then you need to decide: a second alternator, carry enough battery power to match your fuel (and take the useful load reduction), or accept some limit based on the battery(ies) you are willing to carry (1-2 hours is not tough to achieve - depends on the engine of course). Statistically, failure rate does go up with complexity, and this will affect cost (initial purchase and ongoing maintenance), but shouldn't impact safety if you have a failure tolerant design, and follow proper procedures. The added complexity reduces the chances that you will need to land short of your destination, despite a failure. How much is that worth to you? My $0.02 Dennis Glaeser This is really a question for Bob. But here goes to the list anyway. Being new to building a plane and to electrical matters, I read Bob's book cover to cover twice and was sold on the idea of fitting my RV8 with a two alternator, two battery system (two years for each battery). System seems good and it one main advantage: two level redundancy. But a nagging feeling keeps coming back. In an attempt at applying the KISS principle (for those who might not be aware aka 'keep it simple, stupid'), I tell myself would I not be better off with a very simple one battery, one alternator setup? Am I not with all those extra wires and switches and other equipment offsetting the redundancy advantage with a higher risk at having a complexity related failure? That's it - if Bob or anyone else would care to comment? One last thing - I know it is my airplane and that I should do whatever seems best for me - but I would appreciate some enlightened intelligent comments. Regards, Michle Delsol RV8 - Wings going on to the fuselage ________________________________________________________________________________
Subject: Home made VOR/GS antenna
Date: Feb 09, 2005
From: "Bordelon, Greg" <gbordelon(at)hess.com>
I wish to fabricate my own combination "whip" VOR/Glide Slope antenna. Before anyone suggest, I know about the wing tip plate antenna but I don't want to use that. 1st question: Do I attach the center lead to one element and the shield to the other element? Is that all? Or do I need to use ferrite beads near the splitting of coax? If yes, how many and where do I get them from? In Bob's Aeroelectric book, he has a picture of a VOR antenna on page 13-14 without any beads and on page 13-17 is a picture of a glide slope antenna with three ferrite beads. Its unclear to me which method is correct. 2nd question: I will need a splitter or diplexer to attach to the antenna and the VOR and Glide Slope inputs on my radio. I found three manufactures of these; Comant, RA Miller, and Dorne Margolin. How do I determine which of these will perform best? Is there anyone with experience with these that can offer comments? Thanks - Greg ________________________________________________________________________________
From: "Wayne Sweet" <w_sweet(at)comcast.net>
Subject: Re: Home made VOR/GS antenna
Date: Feb 09, 2005
After a recent avionics upgrade, my plane now has two VORs and two GS which uses one antenna and a 1 into 4 splitter. Don't remember the manufacturer, but got it from ACS. I use a "cat whiskers" type VOR/GS antenna (ACS some 15 years ago) and fabricated the connection that memory does not recall exactly how it is connected. But you have part of the idea; the center lead to one terminal and the shield to the other, but as I recall, the same coax is then looped back and connected to the airframe. I am about (in a week or so) to re-route my COM1 coax and will be getting back there in the tailcone to do that. If you still do not have an answer, I will take a picture or two of my connection. BTW, my Terra NAV/COM (200/760 old style push buttons) and GNS430 always pick up the GS (VOR's are not an issue; always good reception) at least 20 nm out. Wayne ----- Original Message ----- From: "Bordelon, Greg" <gbordelon(at)hess.com> Subject: AeroElectric-List: Home made VOR/GS antenna > > > I wish to fabricate my own combination "whip" VOR/Glide Slope antenna. > Before anyone suggest, I know about the wing tip plate antenna but I > don't want to use that. > > 1st question: Do I attach the center lead to one element and the shield > to the other element? Is that all? Or do I need to use ferrite beads > near the splitting of coax? If yes, how many and where do I get them > from? In Bob's Aeroelectric book, he has a picture of a VOR antenna on > page 13-14 without any beads and on page 13-17 is a picture of a glide > slope antenna with three ferrite beads. Its unclear to me which method > is correct. > > 2nd question: I will need a splitter or diplexer to attach to the > antenna and the VOR and Glide Slope inputs on my radio. I found three > manufactures of these; Comant, RA Miller, and Dorne Margolin. How do I > determine which of these will perform best? Is there anyone with > experience with these that can offer comments? > > Thanks - Greg > > > Try www.SPAMfighter.com for free now! ________________________________________________________________________________
Date: Feb 09, 2005
From: Jim and Lucy <jpollard(at)ciaccess.com>
Subject: Re: switch guards
> > I'm using the Space Shuttle replica switch guards in my 8A. http://www.delcity.net/delcity/servlet/catalog?parentid=4810&page=1 this is a link to some other switchguards ________________________________________________________________________________
From: owner-aeroelectric-list-server(at)matronics.com
Subject: Re: Aeroelectric - two battery, two alternator
system
Date: Feb 09, 2005
Dennis, Thank you for your thoughtful reply. The 2 batt/2 alt setup (Z11) did get me excited but the type of flying (very occasional dusk VFR, no IFR, over water at times) plus a common sensical KISS principle to govern decisions may dampen my enthusiasm for Z11. In the final analysis, I think it all boils down to whether I want full electronic ignition, partial, or all mags. I am finishing the wings which means that I have a long way to go - you'll see my posts as the situation evolves. Thanks again, Michle > -----Original Message----- > From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > aeroelectric-list-server(at)matronics.com] On Behalf Of Glaeser, Dennis A > Sent: Wednesday, February 09, 2005 5:06 PM > To: 'AeroElectric-List(at)matronics.com' > Subject: AeroElectric-List: Re: Aeroelectrci - two battery, two alternator > system > > > > Michel, > > What is your anticipated mission profile? What engine are you using? > > The basic decision process I used is this: go down the list of every piece > of equipment on your airplane (instruments, electrical power, radios, > servos, switches, lights ...) and ask yourself - what will I do when (not > if) this fails in-flight? In the case of an alternator, how long can you > operate on battery power until something unacceptable happens - like loss > of > power if you have an electrically dependent engine, or loss of critical > instruments or radios if IFR (and don't forget lights if you fly at > night). > > If you want to be able to continue to your destination no matter what, or > if > you fly where reasonable places to land are few and far between, then > either > dual alternators or enough battery power to outlast your fuel is in order. > > If you have an engine that doesn't require electricity, having enough > battery to run radios and instruments for a long time is not tough to do. > > If your engine requires juice then you need to decide: a second > alternator, > carry enough battery power to match your fuel (and take the useful load > reduction), or accept some limit based on the battery(ies) you are willing > to carry (1-2 hours is not tough to achieve - depends on the engine of > course). > > Statistically, failure rate does go up with complexity, and this will > affect > cost (initial purchase and ongoing maintenance), but shouldn't impact > safety > if you have a failure tolerant design, and follow proper procedures. The > added complexity reduces the chances that you will need to land short of > your destination, despite a failure. How much is that worth to you? > > My $0.02 > > Dennis Glaeser > > > This is really a question for Bob. But here goes to the list > anyway. > > Being new to building a plane and to electrical matters, I read > Bob's book > cover to cover twice and was sold on the idea of fitting my RV8 > with > a two > alternator, two battery system (two years for each battery). > System > seems > good and it one main advantage: two level redundancy. > > But a nagging feeling keeps coming back. In an attempt at applying > the KISS > principle (for those who might not be aware aka 'keep it simple, > stupid'), I > tell myself would I not be better off with a very simple one > battery, one > alternator setup? Am I not with all those extra wires and switches > and other > equipment offsetting the redundancy advantage with a higher risk > at > having a > complexity related failure? > > That's it - if Bob or anyone else would care to comment? > > One last thing - I know it is my airplane and that I should do > whatever > seems best for me - but I would appreciate some enlightened > intelligent > comments. > > Regards, > Michle Delsol > RV8 - Wings going on to the fuselage > > > > > ________________________________________________________________________________
Date: Feb 09, 2005
From: paul wilson <pwilson(at)climber.org>
Subject: Re: switch guards
An inexpensive switch guard you linked to can also be purchased at Autozone in various anodized colors, included is a simple on off switch of questionable heritage. These things have worked fine on my truck for over a year. Other auto parts stores stock the same thing. When the guard is closed it operates the toggle switch at the same time. Paul ========== > > > > > I'm using the Space Shuttle replica switch guards in my 8A. >http://www.delcity.net/delcity/servlet/catalog?parentid=4810&page=1 >this is a link to some other switchguards ________________________________________________________________________________
Date: Feb 09, 2005
From: "Richard V. Reynolds" <rvreynolds(at)macs.net>
Subject: Battery Failure
I have an all electric RV-6A wired per Z-13, with B&C alternator and LR-3 voltage regulator, but without the second alternator. My IFR instructor asked me what happens if in flight 1) the battery shorts out (one or more of the internal plates short) 2) the battery goes dead 3) The positive lead falls off of the battery post (does not ground) 4) the positive lead shorts to ground The batter is a Concord RG (sealed lead acid) Richard Reynolds RV-6A N841RV ________________________________________________________________________________
Subject: Battery Failure
Date: Feb 09, 2005
From: "Chuck Jensen" <cjensen(at)dts9000.com>
The instructor posed interesting questions. However, did he give you the probabilities of each, or any, of these events happenings on a well maintained aircraft? -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Richard V. Reynolds Subject: AeroElectric-List: Battery Failure I have an all electric RV-6A wired per Z-13, with B&C alternator and LR-3 voltage regulator, but without the second alternator. My IFR instructor asked me what happens if in flight 1) the battery shorts out (one or more of the internal plates short) 2) the battery goes dead 3) The positive lead falls off of the battery post (does not ground) 4) the positive lead shorts to ground The batter is a Concord RG (sealed lead acid) Richard Reynolds RV-6A N841RV ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Home made VOR/GS antenna
> >I wish to fabricate my own combination "whip" VOR/Glide Slope antenna. >Before anyone suggest, I know about the wing tip plate antenna but I >don't want to use that. > >1st question: Do I attach the center lead to one element and the shield >to the other element? Is that all? Or do I need to use ferrite beads >near the splitting of coax? If yes, how many and where do I get them >from? In Bob's Aeroelectric book, he has a picture of a VOR antenna on >page 13-14 without any beads and on page 13-17 is a picture of a glide >slope antenna with three ferrite beads. Its unclear to me which method >is correct. The beads offer no practical benefit. When the section on antennas was published, I repeated information offered from other sources. I've since investigated the design in the lab and found that the beads do not change the antenna performance in any meaningful way. >2nd question: I will need a splitter or diplexer to attach to the >antenna and the VOR and Glide Slope inputs on my radio. I found three >manufactures of these; Comant, RA Miller, and Dorne Margolin. How do I >determine which of these will perform best? Is there anyone with >experience with these that can offer comments? They all pretty much perform as advertised. They're not difficult to build so it's unlikely that one brand stands head-n-shoulders above another brand. The simple dipole antenna with coax center conductor to one element and coax shield to the other element will perform very nicely. This style antenna was installed on thousands of Cessna's from the early 50's through late 70's . . . a time that included vacuum tube radios and early solid state. The antennas were NOT the weakest link in the VOR, LOC, GS system. Bob . . . ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: RE: two battery, two alternator system
> >Dennis, > >Thank you for your thoughtful reply. The 2 batt/2 alt setup (Z11) did get me >excited but the type of flying (very occasional dusk VFR, no IFR, over water >at times) plus a common sensical KISS principle to govern decisions may >dampen my enthusiasm for Z11. Let's try to put some things into perspective. There are tons of dark-n-stormy night stories wherein alternators and batteries are star performers in the role of villain. Given the proven reliability of modern automotive alternators . . . in particular the converted Nipon Denso products from B&C . . . probability of alternator failure is a small fraction of what we've come to expect from certified iron. Combine this with the very robust, sealed lead-acid batteries -AND- a truly meaningful preventative maintenance plan and we've beat the worst worries into submission. If one simply installs Van's a-la C-172 wiring with a modern alternator and well maintained RG battery, probability of personalizing a dark-n-stormy night experience over electrical systems issues is very low. By taking advantage of variations on a theme described in the z-figures, one can push those probabilities still lower. In 10+ years of suggesting builders consider the e-bus, I've had only one reader write and tell me the e-bus turned an alternator failure into a ho-hum event. However, I've had perhaps a half dozen people write and thank me for the OVM-14 crowbar ov module. Far more folks have experienced an ov condition that forced alternator shutdown than simple alternator failure. I don't recall the numbers of ov experiences that benefited from an e-bus installation after the alternator was shut off. Even if the builder did not have an e-bus, keeping a well maintained RG battery on board goes a long way to saving the day. >In the final analysis, I think it all boils down to whether I want full >electronic ignition, partial, or all mags. If you go electronic ignition, run p-mags which do not depend on electrical system for system operations. >I am finishing the wings which means that I have a long way to go - you'll >see my posts as the situation evolves. I have a client with enough funds to strive for the "ultimate" system which may include dual efis, dual electronic ignition, dual autopilots . . . For the moment, I'm still trying to justify ruling out a Figure Z-13 installation thus saving about a 12# penalty for going with Z-14. Reliability doesn't have to be heavy or expensive . . . just well considered. Since the e-mag/p-mag guys came along, reliability is getting easier, lighter and less expensive all the time. Bob . . . ________________________________________________________________________________
Date: Feb 09, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Battery Failure
> > >I have an all electric RV-6A wired per Z-13, with B&C alternator and >LR-3 voltage regulator, but without the second alternator. > >My IFR instructor asked me what happens if in flight > >1) the battery shorts out (one or more of the internal plates short) This puts the whole system at risk. A battery with a shorted cell cannot be depended on for power nor can it be left connected to a system with a working alternator. Most folks are wiring their systems such that one cannot take the battery off line and operate alternator-only. This kind of operation has been suggested or even permitted in a very few certified ships. I'm aware of Bonanzas and Barons in particular. The up-side is that probability of shorted cells in an RG battery is a tiny fraction of what our experience has demonstrated with flooded batteries. Further, cells in flooded batteries short after the battery has been used hard and put away wet for so long that chemistry is falling out of the plates . . . the battery's capacity is most certainly degraded to just above useless. If you maintain an RG battery for minimum useful capacity, you can ignore the shorted cell syndrome. >2) the battery goes dead Batteries don't capriciously "go dead" . . . they are (1) run to death by a system that fails to adequately support system loads while the engine is running and/or (2) used far beyond the time when reserve capacity represents a useful store of energy for sustaining flight. >3) The positive lead falls off of the battery post (does not ground) > >4) the positive lead shorts to ground These are the makings for a bad day at Black Rock . . . How do these things happen? If one installs battery fasteners with the same care as one installs prop bolts, then the aforementioned scenarios are not worth considering. While we're considering due diligence, why would the OBAM aircraft mechanic categorize ANY hardware into degrees of diligence required for trouble-free operation? I would hope that a home builder is attuned to system functionality and requirements for trouble free operation irrespective of whether or not the component is 'critical' . . . Like most "what if" discussions, it's the unanticipated, unconsidered scenario that bites you. I was really proud of the last of the mature Bradford Pear trees in our neighborhood. Snuggled between two houses it was protected from winds and had a magnificent 40' canopy. While there was value in protecting the tree from winds, it was an ice storm that ultimately brought the tree down . . with great risk that branches would fall on houses that protected it from winds! Select modern products, use due diligence installing fasteners, minimize electrical stresses to the battery by monitoring charging system performance and finally, take the battery out of service when it won't support the e-bus for duration of fuel aboard. When folks fail to observe one or more of these simple tenets, there are valid concerns for the failure modes cited. This happens to spam can drivers all the time but I trust will never happen to folks who participate on the AeroElectric List . . . Bob . . . ________________________________________________________________________________
Date: Feb 09, 2005
From: "Richard V. Reynolds" <rvreynolds(at)macs.net>
Subject: Re: Battery Failure
Chuck, No probabilities. Just questions, since I don't have a vacuum system. I think Bob's answer will put the discussion to bed. Let's not drag it out (vacuum vs all electric). Richard Reynolds Chuck Jensen wrote: > > The instructor posed interesting questions. However, did he give you the probabilities of each, or any, of these events happenings on a well maintained aircraft? > > -----Original Message----- > From: owner-aeroelectric-list-server(at)matronics.com > [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of > Richard V. Reynolds > To: aeroelectric-list(at)matronics.com > Subject: AeroElectric-List: Battery Failure > > > I have an all electric RV-6A wired per Z-13, with B&C alternator and > LR-3 voltage regulator, but without the second alternator. > > My IFR instructor asked me what happens if in flight > > 1) the battery shorts out (one or more of the internal plates short) > > 2) the battery goes dead > > 3) The positive lead falls off of the battery post (does not ground) > > 4) the positive lead shorts to ground > > The batter is a Concord RG (sealed lead acid) > > Richard Reynolds > RV-6A N841RV > ________________________________________________________________________________
Date: Feb 09, 2005
From: Phil Birkelbach <phil(at)petrasoft.net>
Subject: Garmin 296 Antenna Cable
I just got my Garmin GPSMap 296 and I'd like to semi-permanently mount it into my RV-7. Can anybody see any reason why I could not cut that BNC connector off the end of the antenna cable so that I could feed the cable through a hole smaller than that monster of a plug that comes on the antenna? Godspeed, Phil Birkelbach RV-7 N727WB http://www.myrv7.com ________________________________________________________________________________
From: "Chris Horsten" <airplanes(at)sympatico.ca>
Subject: Garmin 296 Antenna Cable
Date: Feb 09, 2005
Phil. I have the same issue to deal with. I as going to make the hole partly behind the mounting bracket and put a grommet. That way it would not be so obvious when the unit was not in the aircraft. However, I too would be interested in an alternative solution. Chris H CH-300 -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Phil Birkelbach Subject: AeroElectric-List: Garmin 296 Antenna Cable --> I just got my Garmin GPSMap 296 and I'd like to semi-permanently mount it into my RV-7. Can anybody see any reason why I could not cut that BNC connector off the end of the antenna cable so that I could feed the cable through a hole smaller than that monster of a plug that comes on the antenna? Godspeed, Phil Birkelbach RV-7 N727WB http://www.myrv7.com advertising on the Matronics Forums. ________________________________________________________________________________
From: BobsV35B(at)aol.com
Date: Feb 09, 2005
Subject: Re: Garmin 296 Antenna Cable
In a message dated 2/9/2005 9:36:00 P.M. Central Standard Time, airplanes(at)sympatico.ca writes: I just got my Garmin GPSMap 296 and I'd like to semi-permanently mount it into my RV-7. Can anybody see any reason why I could not cut that BNC connector off the end of the antenna cable so that I could feed the cable through a hole smaller than that monster of a plug that comes on the antenna? Godspeed, Phil Birkelbach Good Evening Phil, That would be one solution, but why not drill the hole big enough to allow the connector to go through then use a grommet sized for that hole with an inner hole just big enough for the cable? The grommet can be split to allow it to be put over the cable and it will be held together by insertion into the metal so that the slit wouldn't even be visible. That way, you could install and remove at will. Grommets of suitable diameters are readily available at almost all parts suppliers. Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 ________________________________________________________________________________
Date: Feb 09, 2005
From: Jim Corner <jcorner(at)shaw.ca>
Subject: Garmin 296 Antenna Cable
Bob I replaced the antenna cable plug on my 295 and didn'thave any problems. Can't see why the 296 should be any different Jim > > > In a message dated 2/9/2005 9:36:00 P.M. Central Standard Time, > airplanes(at)sympatico.ca writes: > > I just got my Garmin GPSMap 296 and I'd like to > semi-permanently mount it into my RV-7. Can anybody see any > reason why I could not cut that BNC connector off the end of > the antenna cable so that I could feed the cable through a > hole smaller than that monster of a plug that comes on the antenna? > > Godspeed, > > Phil Birkelbach > > > Good Evening Phil, > > That would be one solution, but why not drill the hole big > enough to allow > the connector to go through then use a grommet sized for that > hole with an > inner hole just big enough for the cable? The grommet can > be split to allow it > to be put over the cable and it will be held together by > insertion into the > metal so that the slit wouldn't even be visible. That way, > you could install > and remove at will. > > Grommets of suitable diameters are readily available at > almost all parts > suppliers. > > Happy Skies, > > Old Bob > AKA > Bob Siegfried > Ancient Aviator > Stearman N3977A > Brookeridge Airpark LL22 > Downers Grove, IL 60516 > 630 985-8502 > > > ========= > Matronics Forums. > ========= > http://www.matronics.com/FAQ/AeroElectric-> List.htm > Search Engine: > http://www.matronics.com/search > ========= > > > > > ________________________________________________________________________________
From: BobsV35B(at)aol.com
Date: Feb 10, 2005
Subject: Garmin 296 Antenna Cable
In a message dated 2/10/2005 8:22:19 A.M. Central Standard Time, jcorner(at)shaw.ca writes: Bob I replaced the antenna cable plug on my 295 and didn't have any problems. Can't see why the 296 should be any different Jim Good Morning Jim, I agree totally, I just thought that it would be nicer if the plug did not have to be cut off each time it was desired to remove the portable unit from the airplane. Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 ________________________________________________________________________________
From: "Dennis Johnson" <pinetownd(at)volcano.net>
Subject: Size of Fuse vs. Circuit Breaker
Date: Feb 10, 2005
Greetings, I'm finally getting to the point of beginning the detailed electrical design stage of my Lancair Legacy. Although I'm planning to use fuses, I noticed in AC 43.13-1B, Table 11-3, that for certain wire sizes, it calls for a substantially larger circuit breaker rating than for a fuse. For example, a 14 AWG wire can be protected by a 20 amp breaker or a 15 amp fuse. Since I'm going to be using nearly all fuses, it doesn't particularly matter to my design, but just for educational purposes, I'm curious. I thought that fuses generally acted faster in response to mild overloads than breakers, but AC 43.13 seems to say the opposite. What gives? Thanks, Dennis Johnson Legacy #257 ________________________________________________________________________________
Date: Feb 10, 2005
Subject: Re: Size of Fuse vs. Circuit Breaker
From: "Matt Prather" <mprather(at)spro.net>
Hi Dennis, I can think of two reasons for what you noticed. Both are pure speculation. The first thing I noticed when looking at the chart was that the fuses were to be of MILF15160 or equivalent. I Google'ed that and found lots of references to it, many mentioning that it had been abandoned. None that I saw (not an exhaustive search) described the technical characteristics of the standard. I wonder if this MIL spec is for a fuse that has relatively slow blow characteristics. The other thing that I noticed about the chart is that the values for the fuses are sometimes equal to the CB value and sometimes less. My other speculation is that they picked commonly available CB ratings, and that in some cases an equivalent fuse rating didn't exist. At the time of the AC writing were there any 7.5A fuses? The only safe choice would be to use the next smaller size fuse. Again, pure speculation on my part. Anyone find this MIL spec? A link to the AC43-13 Chapter 11. http://www.faa.gov/certification/aircraft/av-info/dst/43-13/Ch_11-04.doc Regards, Matt- > > > Greetings, > > I'm finally getting to the point of beginning the detailed electrical > design stage of my Lancair Legacy. Although I'm planning to use fuses, > I noticed in AC 43.13-1B, Table 11-3, that for certain wire sizes, it > calls for a substantially larger circuit breaker rating than for a fuse. > For example, a 14 AWG wire can be protected by a 20 amp breaker or a 15 > amp fuse. > > Since I'm going to be using nearly all fuses, it doesn't particularly > matter to my design, but just for educational purposes, I'm curious. I > thought that fuses generally acted faster in response to mild overloads > than breakers, but AC 43.13 seems to say the opposite. What gives? > > Thanks, > Dennis Johnson > Legacy #257 > > ________________________________________________________________________________
Date: Feb 10, 2005
From: "dedgemon(at)knology.net" <dedgemon(at)knology.net>
Subject: RE:GRT Magnetometer reliance
Mike, et.al. I think that one of the common misconceptions about AHARS units is that are an all digital "analog" of a vacuum gyro system, but if fact they operate very differently. The AHARS units are actually full blown IMU units like we use in missiles, subs, etc... We just don't really care about where we are, just our attitude angles. The basic way that you do this is to use 3 rate gyros and 3 accelerometers and integrate the signals. This allows us to propogate our position and attitude from a "KNOWN" position and attitude. Note that we are just integrating this original data forward, we can't "measure" our attitude with just rate gyros and accels. For that we need something else to reference to. In the missile world we often use GPS data to perform GPS aiding, this works really well, (as long as GPS is up). Note that we also use sensors that are much, much better than whats in the AHARS units that we're all flying (they cost a ton too). So what to do. Everyone that I'm familiar with (Dynon, Blue mountain, GRT, etc...) is using a 3 axis magnetometer (not just a compass, but 3 axis) to provide a nice low frequency stable signal for the Kalman filter. This can work very well and doesn't depend on outside signals. If the magnetometer craps out completely the AHARS solution will start to drift and slowly gets poor (how slow depends on the quality of the sensors). This is much like a vacuum gyro spinning down. But what if the magnetometer starts putting out bad data. If that can be sensed then we're probably better off just shutting the thing down. Hope this helps. --- David Edgemon Summit Research Corp. 256-876-4884 "On the side of the box it said to install Windows 95 or better, so I installed Linux" Anonymous ________________________________ Message 5 _____________________________________ Subject: AeroElectric-List: GRT Magnetometer reliance From: "Stewart, Michael (ISS Atlanta)" <mstewart(at)iss.net> Hey guys, I learned something yesterday that is very important to know. I uploaded the recent software into the GRT EFIS. The upload procedure was... frankly... amazing. Insert usb chip into unit, turn knob, and watch. How cool is that? I walked over to my buddy's house who has the dual units installed and updated his. He thought I was very cool. I told him... Its not me, its GRT. A monkey could do it. A very dumb monkey could do it. Anyway, after the upload my attitude did not work and an e-mail to Todd at GRT resulted in the answer. The new version does not show an attitude if the magnetometer is not connected, or fails. The reason being that it needs that data to complete the AHARS solution for attitude. I am still going back and forth with Todd to determine if there is a better way for them to handle an in flight manometer failure than just going TU, but for now this is the behavior you will see in flight. Since the attitude reading requires compass data, I have asked them to look at some other solution like an "ahars unreliable" flag, or countdown to going TU, or something other than instant TU. I do not know what testing led to this new software change but I have to figure that there is some period of time after loss of compass data that it is usable, or partially usable. Also since it is getting ground track from a gps source over a serial data stream, could this not be used as a backup piece of data while the compass is out? I dunno. But I do know "Other" competitors do not rely on external devices to complete the solution for attitude. Thoughts group? Mike Stewart Basement flying the GRT. S8 FWF ________________________________________________________________________________
Date: Feb 10, 2005
From: Phil Birkelbach <phil(at)petrasoft.net>
Subject: Re: Garmin 296 Antenna Cable
I have no intention of ever removing the antenna from the plane. I will remove the GPS but the antenna is permanent, if I need another antenna I'll just buy one. I appreciate everyone's comments. I'll probably cut that thing off this weekend and see if it works. I'll try to remember to report my results. Godspeed, Phil Birkelbach - Houston Texas RV-7 N727WB - Panel http://www.myrv7.com BobsV35B(at)aol.com wrote: > > >In a message dated 2/10/2005 8:22:19 A.M. Central Standard Time, >jcorner(at)shaw.ca writes: > >Bob > >I replaced the antenna cable plug on my 295 and didn't have any problems. >Can't see why the 296 should be any different > >Jim > > >Good Morning Jim, > >I agree totally, I just thought that it would be nicer if the plug did not >have to be cut off each time it was desired to remove the portable unit from >the airplane. > >Happy Skies, > >Old Bob >AKA >Bob Siegfried >Ancient Aviator >Stearman N3977A >Brookeridge Airpark LL22 >Downers Grove, IL 60516 >630 985-8502 > > > > ________________________________________________________________________________
Date: Feb 10, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Size of Fuse vs. Circuit Breaker
> > >Greetings, > >I'm finally getting to the point of beginning the detailed electrical >design stage of my Lancair Legacy. Although I'm planning to use fuses, I >noticed in AC 43.13-1B, Table 11-3, that for certain wire sizes, it calls >for a substantially larger circuit breaker rating than for a fuse. For >example, a 14 AWG wire can be protected by a 20 amp breaker or a 15 amp fuse. > >Since I'm going to be using nearly all fuses, it doesn't particularly >matter to my design, but just for educational purposes, I'm curious. I >thought that fuses generally acted faster in response to mild overloads >than breakers, but AC 43.13 seems to say the opposite. What gives? In a nutshell . . . selection of a wire size is driven by two considerations: (1) temperature rise as it affects the insulation on the wire and (2) voltage drop to be tolerated over the length of the wire run. The copper in a 22AWG wire will very happily carry 15 amps at room temperature and free air. I just hooked a 16" piece of 22759/16 to a power supply and jacked it up to 15 amps. 20 minutes later, the wire was way too hot to touch. Voltage drop was about 0.7 volts. No smells. No smoke. If this had been PVC wire instead of Tefzel, perhaps the PVC would have melted off the wire . . . no sweat, go with Teflon. The REAL answers to your questions are: (1) how will the wire to be protected be loaded? to 200 amps or more to crank an engine. Is this a bad deal? AC43-13 sez protect this wire at 100A breakers or 70A with fuses. Section 5 of Chapter 11 goes into lots of explanation for rating wires and takes voltage drop and temperature rise into consideration. Table 11-9 speaks to continuous current ratings for wire but consider notes at the bottom of the table where one reads that the numbers apply for 70C ambients and free air . . . higher ambient temps and burying a wire inside a bundle gives one reasons to derate a wire still further. One can tolerate what might be considered severe overloading for short times as long as voltage drop can be tolerated. I recommend 4AWG fat wiring for aircraft where battery is very close to engine. When battery and engine are on opposite ends of airplane, 2AWG is recommended. In some seaplanes, 0AWG is called for. This decision is driven by voltage drop issues during cranking. (2) what is the temperature rating of the insulation on the wire? issues, then insulation sets the current limits 105C, Tefzel limits at 150C, Teflon goes to 200C. Got some asbestos sleeving laying around? Slip that stuff over your wire and you can run it up to cherry red temperatures. Is the wire hanging out in the breeze for cooling or is it wrapped up in a bundle with lots of other wires that contribute their own heat dissipations to the equation. Note that we STILL haven't talked about fuses or circuit breakers. (3) what kind of load does the wire feed? be considered? Fuses tend to be faster than thermal breakers. Magnetic breakers are faster than most fuses. Virtually ANY form of circuit protection can be sized to adequately protect ANY wire. You won't find a considered one-size-fits-all from the charts and tables. A good case in point deals with pitot tube heaters. Cold resistance is very high and warmup speeds relatively slow. Some builders have resorted to 30A fuses to protect a 14AWG wire driving a 100W heated pitot that runs under 10 amps after it warms up. The charts and tables will be conservative suggestions that cover most situations but understand that some systems will present special issues that drive CONSIDERED departure from suggestions. There's no substitute for knowing how the system works and selecting both wire and circuit protection based on that understanding. Bob . . . ________________________________________________________________________________
Date: Feb 10, 2005
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: RE: shielded wires
0$60085fd8@scottcomp> >Hi Bob , thanx for getting back to me. I have a Stratomaster Ultra which has >a very poor wiring diagram and a flightcom 11gx intercom that on my previous >plane I tried to wire to ship power and had to go back to it's internal >battery due to ignition noise .I want to hard wire a hand held GPS and COM >as well as the intercom to ships power on my sonex and don't want the noise. >I got all the sheilded wire for free from work. Im not real clear on what >wires I should sheild so as I have the wire I thought , everything! This is >no dought over kill but I dont want noise . The engine I'm using has 2 mags >and electronic ignition it's the aero vee from sonex. I had planned on using >ACS keyed ignition switch for the mags and a toggle switch for the >electronic ignition. Any help you can give would be really great as this >set up is very close to my last plane , and it had noise! Scott Cameron . >sonex164(at)netscape.ca Okay. First, it's unlikely that shielding ANY wires will offer a significant degree of noise reduction. 95% plus of all noise problems are either conducted noise, ground loop noise, or RF radiated noise. I can't recall the last time I fixed a problem by shielding wire(s). What KIND of noise were you hearing? Ignition? Alternator? Some other antagonist. Given the simplicity of this airplane, lets just wire-er-up and see what happens. If you do have a noise problem, we need to deduce antagonist and propagation mode. It's most likely that your problems were either conducted in on the 14vdc power (needs a filter) or radiated into the antenna (here you may be hosed . . . some folks have had a difficult time getting some ignition systems to shut up). Bob . . . ________________________________________________________________________________
Date: Feb 10, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Size of Fuse vs. Circuit Breaker - Corrected
> > >Greetings, > >I'm finally getting to the point of beginning the detailed electrical >design stage of my Lancair Legacy. Although I'm planning to use fuses, I >noticed in AC 43.13-1B, Table 11-3, that for certain wire sizes, it calls >for a substantially larger circuit breaker rating than for a fuse. For >example, a 14 AWG wire can be protected by a 20 amp breaker or a 15 amp fuse. > >Since I'm going to be using nearly all fuses, it doesn't particularly >matter to my design, but just for educational purposes, I'm curious. I >thought that fuses generally acted faster in response to mild overloads >than breakers, but AC 43.13 seems to say the opposite. What gives? In a nutshell . . . selection of a wire size is driven by two considerations: (1) temperature rise as it affects the insulation on the wire and (2) voltage drop to be tolerated over the length of the wire run. The copper in a 22AWG wire will very happily carry 15 amps at room temperature and free air. I just hooked a 16" piece of 22759/16 to a power supply and jacked it up to 15 amps. 20 minutes later, the wire was way too hot to touch. Voltage drop was about 0.7 volts. No smells. No smoke. If this had been PVC wire instead of Tefzel, perhaps the PVC would have melted off the wire . . . no sweat, go with Teflon. The REAL answers to your questions are: (1) how will the wire to be protected be loaded? Discussion: We routinely load 4AWG FAT wires in our airplanes to 200 amps or more to crank an engine. Is this a bad deal? AC43-13 sez protect this wire at 100A breakers or 70A with fuses. Section 5 of Chapter 11 goes into lots of explanation for rating wires and takes voltage drop and temperature rise into consideration. Table 11-9 speaks to continuous current ratings for wire but consider notes at the bottom of the table where one reads that the numbers apply for 70C ambients and free air . . . higher ambient temps and burying a wire inside a bundle gives one reasons to derate a wire still further. One can tolerate what might be considered severe overloading for short times as long as voltage drop can be tolerated. I recommend 4AWG fat wiring for aircraft where battery is very close to engine. When battery and engine are on opposite ends of airplane, 2AWG is recommended. In some seaplanes, 0AWG is called for. This decision is driven by voltage drop issues during cranking. (2) what is the temperature rating of the insulation on the wire? Discussion: As long as you're not dealing with voltage drop issues, then insulation sets the current limits 105C, Tefzel limits at 150C, Teflon goes to 200C. Got some asbestos sleeving laying around? Slip that stuff over your wire and you can run it up to cherry red temperatures. Is the wire hanging out in the breeze for cooling or is it wrapped up in a bundle with lots of other wires that contribute their own heat dissipations to the equation. Note that we STILL haven't talked about fuses or circuit breakers. (3) what kind of load does the wire feed? Discussion: Are there large inrush or high momentary loads to be considered? Fuses tend to be faster than thermal breakers. Magnetic breakers are faster than most fuses. Virtually ANY form of circuit protection can be sized to adequately protect ANY wire. You won't find a considered one-size-fits-all from the charts and tables. A good case in point deals with pitot tube heaters. Cold resistance is very high and warmup speeds relatively slow. Some builders have resorted to 30A fuses to protect a 14AWG wire driving a 100W heated pitot that runs under 10 amps after it warms up. The charts and tables will be conservative suggestions that cover most situations but understand that some systems will present special issues that drive CONSIDERED departure from suggestions. There's no substitute for knowing how the system works and selecting both wire and circuit protection based on that understanding. Bob . . . ________________________________________________________________________________
Date: Feb 10, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Big H-bridge for Big Motors
Here's a sketch of an h-bridge configuration I've used many times for big motors. The parts shown will easily handle motors up to and including 10A if the transistors (especially the p-channel) are heat-sinked. Bob . . . -------------------------------------------------------- < Throughout history, poverty is the normal condition > < of man. Advances which permit this norm to be > < exceeded -- here and there, now and then -- are the > < work of an extremely small minority, frequently > < despised, often condemned, and almost always opposed > < by all right-thinking people. Whenever this tiny > < minority is kept from creating, or (as sometimes > < happens) is driven out of a society, the people > < then slip back into abject poverty. > < > < This is known as "bad luck". > < -Lazarus Long- > <------------------------------------------------------> http://www.aeroelectric.com ________________________________________________________________________________
Date: Feb 10, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Big H-bridge for Big Motors
Guess it would help if I put the link in too . . . http://www.aeroelectric.com/Pictures/Big_H-Bridge.gif > > >Here's a sketch of an h-bridge configuration I've used many >times for big motors. The parts shown will easily handle motors >up to and including 10A if the transistors (especially the >p-channel) are heat-sinked. > > > Bob . . . ________________________________________________________________________________
Date: Feb 11, 2005
From: Frank & Dorothy <frankv(at)infogen.net.nz>
Subject: Re: Big H-bridge for Big Motors
Robert L. Nuckolls, III wrote: >Guess it would help if I put the link in too . . . > >http://www.aeroelectric.com/Pictures/Big_H-Bridge.gif > > Hi I'm not sure what application this Big H-bridge is intended for, but I've had a bit of experience with *little* H-bridges. After burning up a few drive transistors (check out what happens if both drive transistors are enabled at once), I moved to a so-called 'smokeless' H-bridge... a simple 2-to-4 decoder IC (or circuit) prevents bad things from happening. Smart guys even used the 4th state as a brake. Frank ________________________________________________________________________________
Date: Feb 11, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Big H-bridge for Big Motors
There was a discussion on the list concerning solid state replacement of relays with transistors for driving motors up to 7 amps or so. Yes, virtually ALL h-bridge designs are vulnerable to the condition you mentioned . . . One benefit of relays is that they can be wired so that contrary commands translate into simple, smoke-free stopping of the motor. One should take care to design switching systems that drive h-bridges to preclude simultaneous contrary commands via gates or architecture of the control switches. Either may be accomplished easily. Bob . . . > > >Robert L. Nuckolls, III wrote: > > >Guess it would help if I put the link in too . . . > > > >http://www.aeroelectric.com/Pictures/Big_H-Bridge.gif > > > > >Hi > >I'm not sure what application this Big H-bridge is intended for, but >I've had a bit of experience with *little* H-bridges. After burning up a >few drive transistors (check out what happens if both drive transistors >are enabled at once), I moved to a so-called 'smokeless' H-bridge... a >simple 2-to-4 decoder IC (or circuit) prevents bad things from >happening. Smart guys even used the 4th state as a brake. > >Frank ________________________________________________________________________________
From: "Jerry Ballard" <jbyrd@jbyrd-b52.com>
Subject: Battery cables for aft batterys on RV-7
Date: Feb 11, 2005
I've just ordered an H-6 Subaru for an RV-7A. For CG I'll probably need to locate batteries in or aft of baggage compartment. Question1: What size wire should I run from batteries to engine compartment? Should this be a welding cable type wire? With the H-6, reducing weight is more of a concern. Question 2: I've already placed conduit to run power and/or signal wiring for AOA, Whelen strobes, and Grand Rapids EFIS from front to aft of baggage compartment. Can the battery cable be run in this conduit or should it be relocated for separation from routine power and signal wires. How much separation? Jerry ________________________________________________________________________________
Date: Feb 11, 2005
From: "Bob C. " <flyboy.bob(at)gmail.com>
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Bob, I don't understand you example: "A good case in point deals with pitot tube heaters. Cold resistance is very high and warmup speeds relatively slow. Some builders have resorted to 30A fuses to protect a 14AWG wire driving a 100W heated pitot that runs under 10 amps after it warms up." If "cold resistance" is "hign" then current would be low. Why would you need to "resort to 30A fuse"? Thanks, Bob ________________________________________________________________________________
Date: Feb 11, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> Corrected
Subject: Re: Size of Fuse vs. Circuit Breaker -
Corrected Corrected > >Bob, > >I don't understand you example: > >"A good case in point deals with pitot tube heaters. Cold resistance >is very high and warmup speeds relatively slow. Some builders have >resorted to 30A fuses to protect a 14AWG wire driving a 100W heated >pitot that runs under 10 amps after it warms up." > >If "cold resistance" is "hign" then current would be low. Why would >you need to "resort to 30A fuse"? Good eye. Got my tongue tangled around my eyeteeth and couldn't see what I was saying. Cold resistance is LOW and inrush currents are HIGH. Further, due to slow response for temperature rise, this "inrush" current is rather extended . . . it takes about a minute for the temperature of the tube to reach final operating values in flight. The upshot is that builders have selected 14 AWG wire for low voltage drop and 30A fuses so that the relatively fast fuse is not nuisance tripped by the unique warm-up characteristics of a pitot tube that only draws about 10A in operation. Thanks for the heads-up. Bob . . . ________________________________________________________________________________
Date: Feb 11, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Size of Fuse vs. Circuit Breaker - Final Correction
> > >Greetings, > >I'm finally getting to the point of beginning the detailed electrical >design stage of my Lancair Legacy. Although I'm planning to use fuses, I >noticed in AC 43.13-1B, Table 11-3, that for certain wire sizes, it calls >for a substantially larger circuit breaker rating than for a fuse. For >example, a 14 AWG wire can be protected by a 20 amp breaker or a 15 amp fuse. > >Since I'm going to be using nearly all fuses, it doesn't particularly >matter to my design, but just for educational purposes, I'm curious. I >thought that fuses generally acted faster in response to mild overloads >than breakers, but AC 43.13 seems to say the opposite. What gives? In a nutshell . . . selection of a wire size is driven by two considerations: (1) temperature rise as it affects the insulation on the wire and (2) voltage drop to be tolerated over the length of the wire run. The copper in a 22AWG wire will very happily carry 15 amps at room temperature and free air. I just hooked a 16" piece of 22759/16 to a power supply and jacked it up to 15 amps. 20 minutes later, the wire was way too hot to touch. Voltage drop was about 0.7 volts. No smells. No smoke. If this had been PVC wire instead of Tefzel, perhaps the PVC would have melted off the wire . . . no sweat, go with Teflon. The REAL answers to your questions are: (1) how will the wire to be protected be loaded? Discussion: We routinely load 4AWG FAT wires in our airplanes to 200 amps or more to crank an engine. Is this a bad deal? AC43-13 sez protect this wire at 100A breakers or 70A with fuses. Section 5 of Chapter 11 goes into lots of explanation for rating wires and takes voltage drop and temperature rise into consideration. Table 11-9 speaks to continuous current ratings for wire but consider notes at the bottom of the table where one reads that the numbers apply for 70C ambients and free air . . . higher ambient temps and burying a wire inside a bundle gives one reasons to derate a wire still further. One can tolerate what might be considered severe overloading for short times as long as voltage drop can be tolerated. I recommend 4AWG fat wiring for aircraft where battery is very close to engine. When battery and engine are on opposite ends of airplane, 2AWG is recommended. In some seaplanes, 0AWG is called for. This decision is driven by voltage drop issues during cranking. (2) what is the temperature rating of the insulation on the wire? Discussion: As long as you're not dealing with voltage drop issues, then insulation sets the current limits 105C, Tefzel limits at 150C, Teflon goes to 200C. Got some asbestos sleeving laying around? Slip that stuff over your wire and you can run it up to cherry red temperatures. Is the wire hanging out in the breeze for cooling or is it wrapped up in a bundle with lots of other wires that contribute their own heat dissipations to the equation. Note that we STILL haven't talked about fuses or circuit breakers. (3) what kind of load does the wire feed? Discussion: Are there large inrush or high momentary loads to be considered? Fuses tend to be faster than thermal breakers. Magnetic breakers are faster than most fuses. Virtually ANY form of circuit protection can be sized to adequately protect ANY wire. You won't find a considered one-size-fits-all from the charts and tables. A good case in point deals with pitot tube heaters. Cold resistance is very LOW compared to operating resistance. Further, warmup speed is relatively slow. Some builders have resorted to 30A fuses to protect a 14AWG wire driving a 100W heated pitot that runs under 10 amps after it warms up. The charts and tables will be conservative suggestions that cover most situations but understand that some systems will present special issues that drive CONSIDERED departure from suggestions. There's no substitute for knowing how the system works and selecting both wire and circuit protection based on that understanding. Bob . . . ________________________________________________________________________________
Date: Feb 11, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: Battery cables for aft batterys on RV-7
Hi Jerry, To size the cable, you need to know how much current the starter will draw. No one seems to be able to tell me, but hopefully when I get my engine, I'll just test it. I've heard some pretty small numbers thrown around, since it is supposed to have a "geared starter". Also, I really don't know what kind of voltage drop the starter can handle, and still crank the engine. The engine supplier recommends AWG#6, and I hope that will work, since that's what I have installed now. If it doesn't work right, I've got a bunch of Eric's Super-2-CCA Fat Wire standing by. Mickey Jerry Ballard wrote: > > I've just ordered an H-6 Subaru for an RV-7A. For CG I'll probably > need to locate batteries in or aft of baggage compartment. > > Question1: What size wire should I run from batteries to engine > compartment? Should this be a welding cable type wire? With the > H-6, reducing weight is more of a concern. > > Question 2: I've already placed conduit to run power and/or signal > wiring for AOA, Whelen strobes, and Grand Rapids EFIS from front to aft > of baggage compartment. Can the battery cable be run in this conduit > or should it be relocated for separation from routine power and signal > wires. How much separation? > > Jerry -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
From: "Mitch Faatz" <mitchf(at)skybound.com>
Subject: Toggle switch - both master/battery and starter
Date: Feb 11, 2005
With the goal of reducing my switch count, I'm wondering if it's possible to double up the Master/Battery toggle and Starter switch but not sure it's possible toggle-switch-wise. At first I thought if I could find a DPDT switch that is Off-On-(On), I could do it. I've found a red toggle switchguard that returns a toggle that is in the top position back to center (which would drop starter back to master on) and leave a toggle that is in the bottom position alone (master off stays master off). Useability sounds good, switch guard up, switch to master on, momentary full up for starter, returns to master on. With a DPDT switch I could have one pole control starter, but I'm worried about the master/battery pole. If it goes from middle position (on) to up position (momentary on for starter), will there be a brief interruption and if so will that cause a problem? Thanks in advance for any thoughts on this - Mitch Faatz RV-6A Finish Kit Auburn, CA ________________________________________________________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: Re: Big H-bridge for Big Motors
Date: Feb 11, 2005
>One should take care to design switching systems that drive >h-bridges to preclude simultaneous contrary commands via >gates or architecture of the control switches. Either may >be accomplished easily. >Bob . . . > > >Robert L. Nuckolls, III wrote: > > >Guess it would help if I put the link in too . . . > > > >http://www.aeroelectric.com/Pictures/Big_H-Bridge.gif > >I'm not sure what application this Big H-bridge is intended for, but >I've had a bit of experience with *little* H-bridges. After burning up a >few drive transistors (check out what happens if both drive transistors >are enabled at once), I moved to a so-called 'smokeless' H-bridge... a >simple 2-to-4 decoder IC (or circuit) prevents bad things from >happening. Smart guys even used the 4th state as a brake. Having had a couple H-bridge designs shoot thru--one is advised to explore the stunningly simple and reliable intergrated circuit solutions for this design. They offer feature that you simply could not cobble together in the conventional designs---even the very clever conventional designs. For example IR3220S coupled to a pair of IRF7484Q's is 6A continuous WITHOUT a heatsink--and offers shoot-thru protection, Sleep mode, braking, torque control, self-adaptive dead time (don't ask!!!), over-temp, over-current, soft start, inrush limits, etc etc. This results in magnitudes better performance and reliability for less cost and much less size and weight. The PCB is one square inch. AN-1032 application note has everything you ever wanted to know on the subject. Not at all complicated but some SMD assembly skill is required. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net "I only regret my economies." Reynolds Price ________________________________________________________________________________
Subject: Toggle switch - both master/battery and starter
Date: Feb 11, 2005
From: "Mark R Steitle" <mark.steitle(at)austin.utexas.edu>
Mitch, That sounds like what Bob recommends in his "book", and what I purchased from B&C. It is an OFF-ON-(ON) switch. I believe it is p/n S700-2-50 (Bob can verify this). Wire it like Bob shows and it should work great. I have been looking for a switch guard that returns the switch to the center position. Can you post the source and p/n? Thanks, Mark S. -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Mitch Faatz Subject: AeroElectric-List: Toggle switch - both master/battery and starter With the goal of reducing my switch count, I'm wondering if it's possible to double up the Master/Battery toggle and Starter switch but not sure it's possible toggle-switch-wise. At first I thought if I could find a DPDT switch that is Off-On-(On), I could do it. I've found a red toggle switchguard that returns a toggle that is in the top position back to center (which would drop starter back to master on) and leave a toggle that is in the bottom position alone (master off stays master off). Useability sounds good, switch guard up, switch to master on, momentary full up for starter, returns to master on. With a DPDT switch I could have one pole control starter, but I'm worried about the master/battery pole. If it goes from middle position (on) to up position (momentary on for starter), will there be a brief interruption and if so will that cause a problem? Thanks in advance for any thoughts on this - Mitch Faatz RV-6A Finish Kit Auburn, CA ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Re: Battery cables for aft batterys on RV-7
Date: Feb 12, 2005
Mickey, For an apples-oranges comparison: I've got AWG 6 on my 17 Ah battery to run my EJ-18 starter on my EJ-25 engine and the engine cranks like mad. So far the apples. As for the oranges: my battery is on my firewall rather than in the back, which results in about 60 cm (2 ft) of cable. Hope this is of some use Cheers, Hans ----- Original Message ----- From: "Mickey Coggins" <mick-matronics(at)rv8.ch> Subject: Re: AeroElectric-List: Battery cables for aft batterys on RV-7 > > The engine supplier recommends AWG#6, and I > hope that will work, since that's what I > have installed now. ________________________________________________________________________________
Date: Feb 11, 2005
From: "Bob C. " <flyboy.bob(at)gmail.com>
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Bob, What's you conclusion on the pitot heater example . . . what would the appropriate wire size be 14, 16 or 18? Thanks, Bob wrote: Corrected > > > > > >Bob, > > > >I don't understand you example: > > > >"A good case in point deals with pitot tube heaters. Cold resistance > >is very high and warmup speeds relatively slow. Some builders have > >resorted to 30A fuses to protect a 14AWG wire driving a 100W heated > >pitot that runs under 10 amps after it warms up." > > > >If "cold resistance" is "hign" then current would be low. Why would > >you need to "resort to 30A fuse"? > > Good eye. Got my tongue tangled around my eyeteeth and couldn't > see what I was saying. Cold resistance is LOW and inrush currents > are HIGH. Further, due to slow response for temperature rise, this > "inrush" current is rather extended . . . it takes about a minute > for the temperature of the tube to reach final operating values > in flight. > > The upshot is that builders have selected 14 AWG wire for > low voltage drop and 30A fuses so that the relatively fast > fuse is not nuisance tripped by the unique warm-up characteristics > of a pitot tube that only draws about 10A in operation. > > Thanks for the heads-up. > > Bob . . . > > > ________________________________________________________________________________
From: N27160(at)aol.com
Date: Feb 11, 2005
Subject: Coax connector Garmin 196
I have a Garmin 196 and to keep the mounting as tight as possible, I need a coax connector for the antenna to be as compact as possible. A regular straight connector is gonna require me to drill a hole behind the 196. Any ideas for an alternative? ________________________________________________________________________________
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Date: Feb 11, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
We have a run of about 25' from the fuse panel to the pitot tube for an plastic airplane. That's 50' roundtrip. We used 11 amps start and ending at 7.5 to 8 for steady state. Installed 12 AWG. The pitot heat is the biggest current draw of anything in the aircraft - by a factor of about 2 to 3. Incidentally, the wire is in a conduit for about 75-80% of its length. John > > What's you conclusion on the pitot heater example . . . what would the > appropriate wire size be 14, 16 or 18? > > Thanks, > Bob > ________________________________________________________________________________
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Date: Feb 11, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
Mark - Of course, the starter draws more. But after that, can you think of any item that can draw 11 amps. If so, let me know. I always have the felling that we have forgotten something. :-)) BTW, Steve Davis said to tell you hello. We didn't get to go for barbecue this time!! Cheers, John > The pitot heat is the biggest current draw of anything in the aircraft - > by a factor of about 2 >>> > What, are ya hand-proppin' this baby?! ________________________________________________________________________________
Date: Feb 12, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> Corrected
Subject: Re: Size of Fuse vs. Circuit Breaker -
Corrected Corrected > >Bob, > >What's you conclusion on the pitot heater example . . . what would the >appropriate wire size be 14, 16 or 18? How big a pitot heater? They come in 100, 150 and 200 watt sizes or more. How much wire does it take to wire up the pitot tube? If you have a plastic airplane, remember that TOTAL path length includes a return ground wire. If you want the 99.9% UNIVERSAL answer, you can wire with 10AWG protected with a 30A fuse with a very high probability of satisfactory operation. Recall that fuses/breakers protect wire, wire needs to be of sufficient size that voltage drops and temperature rises are tolerable. So, wiring up with some configuration that many folks would consider overkill, it is not incorrect. Voltage drops and temperature rises will be very acceptable and the wire run is adequately protected. If you went with the 14AWG/30A example I cited earlier, you're going to have a 99.0 or better probability of success. Cookbook wiring philosophies tend conservative and assume that your selection of parts and operation of the airplane is not out of the ordinary. As a designer, I make it a goal to understand the performance characteristics of all the parts so that the installation is well considered and not overly heavy or expensive. My decisions can affect the condition of hundreds of airplanes over decades of future usage. You're only building one airplane so the total impact of the conservative solution is measured at worst in a few dollars and a pound or two. The vast majority of OBAM aircraft builders are doing this because they desire the performance and maintenance alternatives to over-regulated, technically-stagnated commercial products. Most builders are installing Van's or Tony B's suggestions that duplicate what's sold out of the spam can factories. They will probably be perfectly happy with their decision. I presume folks on this list server are interested in looking beyond the "norm" to consider ideas that my compatriots in the certified side can only dream about. Forgive me if this isn't the answer you were looking for but please understand that I can't give you the considered answer without having more data about the parts you've selected and the machine you're building. I'll suggest further that after you've gathered all the information needed, you'll be 95% of the way to a goal of answering the question yourself. The discovery process of gathering data is always the most time consuming. Analysis of the discoveries for the purpose of fine-tuning a design is simple. Bob . . . ________________________________________________________________________________
Date: Feb 12, 2005
From: "Bob C. " <flyboy.bob(at)gmail.com>
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Bob, The reason I asked . . . I'm building a RV-8 that was partially completed by another builder . . . he had installed a Gretz Aero AN5812 heated pitot. The installation instruction say it will draw from 6.4 to 8.0 amps which would put it in the 100W range. The predecessor builder had run 16AGW from the pitot to the wing root . . . I was planning on finishing the circuit with 16 and putting a 10A switch/breaker in to feed this device. Sounds like it "could be" a little light on start up? I learn a lot from this list!? Thanks, Bob Christensen wrote: Corrected > > > > > >Bob, > > > >What's you conclusion on the pitot heater example . . . what would the > >appropriate wire size be 14, 16 or 18? > > How big a pitot heater? They come in 100, 150 and 200 watt sizes > or more. How much wire does it take to wire up the pitot tube? If > you have a plastic airplane, remember that TOTAL path length includes > a return ground wire. If you want the 99.9% UNIVERSAL answer, you can > wire with 10AWG protected with a 30A fuse with a very high probability > of satisfactory operation. Recall that fuses/breakers protect wire, > wire needs to be of sufficient size that voltage drops and temperature > rises are tolerable. So, wiring up with some configuration that > many folks would consider overkill, it is not incorrect. Voltage > drops and temperature rises will be very acceptable and the wire > run is adequately protected. If you went with the 14AWG/30A > example I cited earlier, you're going to have a 99.0 or > better probability of success. > > Cookbook wiring philosophies tend conservative and assume that > your selection of parts and operation of the airplane is not > out of the ordinary. As a designer, I make it a goal to understand > the performance characteristics of all the parts so that the > installation is well considered and not overly heavy or expensive. > My decisions can affect the condition of hundreds of airplanes > over decades of future usage. You're only building one airplane > so the total impact of the conservative solution is measured > at worst in a few dollars and a pound or two. > > The vast majority of OBAM aircraft builders are doing this > because they desire the performance and maintenance alternatives > to over-regulated, technically-stagnated commercial products. > Most builders are installing Van's or Tony B's suggestions > that duplicate what's sold out of the spam can factories. > They will probably be perfectly happy with their decision. > > I presume folks on this list server are interested in looking > beyond the "norm" to consider ideas that my compatriots in > the certified side can only dream about. Forgive me if this > isn't the answer you were looking for but please understand > that I can't give you the considered answer without having > more data about the parts you've selected and the machine you're > building. I'll suggest further that after you've gathered > all the information needed, you'll be 95% of the way > to a goal of answering the question yourself. The discovery > process of gathering data is always the most time consuming. > Analysis of the discoveries for the purpose of fine-tuning > a design is simple. > > Bob . . . > > > > ________________________________________________________________________________
Date: Feb 12, 2005
From: Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com>
Subject: Wing wiring grounds
I'm building an RV and priming... Perhaps this question is obvious to some, but not to me. Is it good practice to ground landing lights, heated pitot and position lights to the airframe or are return wires required for each? If airframe ground is okay then how does one do that to insure safe and secure contact? Anyone know how many folks use 14v power versus 24v? I ran across a power supply board design that could output both. Seems like a neat idea, but the converter hw is an additional point of failure. Thanks, Jay ===== __________________________________ ________________________________________________________________________________
From: "Mitch Faatz" <mitchf(at)skybound.com>
Subject: Re: Toggle switch - both master/battery and starter
Date: Feb 12, 2005
> I have been looking for a switch guard that returns the switch to the > center position. Can you post the source and p/n? http://www.vickers-systems.com/pdfs/power/accessories.pdf#search='ms25221' Switch Guard Code Numbers 3, 13, and 14 work this way, looks like 13 or 14 are the type I would want (they only differ in location of Keyway tab, which I haven't figure out the correct orientation of yet). Mitch Faatz RV-6A Finish Kit Auburn, CA ________________________________________________________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: Pitot Tubes
Date: Feb 12, 2005
Pitot tubes use a huge amount of power. The last time this matter seems to have been studied in small aircraft at subsonic speeds was....ah....1928...and they determined that Pitot tubes along with wing-wires can collect ice! There is so little information online about the subject that a Google search of heated pitot tubes come up with "Do you mean...Heated Pilot tubes"? Now there's an image....Hey Bob, I think I feel some rain. Could you build a Pitot tube that remained ice-free and had no heater---Certainly. It's not even very hard. Could you spritz Miracle-Spray on the tube to stave off ice accumulation?---Certainly. Could you use an iced Pitot tube to tell you to get the heck out of there 'cause you aren't delivering the anti-toxin?---Oh man....Yes. Could you use slip a sock over the metal tube to conserve warmth and turn down the current? Why not. I have a little write-up on my own thermostatic heated pitot tube which I can immodestly claim is light years ahead of AN5812. See http://www.periheliondesign.com/downloads.htm Imagine what a Pitot tube actually does--It keeps a tiny little space warm enough to keep a hole open and ice-free in the direction of flight. The surrounding air cools it off and it reaches some temperature equilibrium determined by the heater and cooling by the air flow. Could you build a Pitot tube that remained ice-free and had no heater---Certainly. It's not even very hard. Could you spritz Miracle-Spray on the tube to stave off ice accumulation?---Certainly. Could you use an iced Pitot tube to tell you to get the heck out of there 'cause you aren't delivering the anti-toxin?---Oh man....Yes. Could you use slip a sock over the metal tube to conserve warmth and turn down the current? Why not? Could you put a current regulator into the circuit and only crank it up if needed? Sure! More than most other aircraft parts, Pitot tube design is dragged down by the rules and regulations. But if you don't have to use the old dog-leg, bring it up to modern times. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net ________________________________________________________________________________
Subject: Re: Wing wiring grounds
Date: Feb 12, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
Jay - Check the archives. Bob has answered this several times. As I recall, it is OK to do this for these systems, but I'd check for sure. John > I'm building an RV and priming... Perhaps this question is obvious to > some, but not to me. Is it good practice to ground landing lights, > heated pitot and > position lights to the airframe or are return wires required for each? If > airframe ground is okay then how does one do that to insure safe and > secure contact? ________________________________________________________________________________
From: "Nigel Harrison" <naharrison(at)manx.net>
Subject: Advice about 24V systems
Date: Feb 12, 2005
Dear All, I am a Europa builder and am planning to install an all-electric set up with a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring, he is of the opinion that a 24V electrical system will provide much more safety margin tha a 12V system in the event of generator failure. My aircraft will have a Rotax 912S. The engine manufacturers have advised me that "Unfortunately the Rotax electrical system is only 12 V DC.The internal alternator gives an AC voltage above 24 V at a speed of about 3000 rpm, which may possibly be suitable, but you would have to design or procure a rectifier/regulator for 24 V." Can someone advise me whether this alternator would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series. Rotax also mention a rectifier/regulator. Advice on this too would be useful. I have little in the way of electrical knowledge/knowhow, so simple explanations would be most helpful. Thanks Nigel Harrison **************************************************************** This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus **************************************************************** ________________________________________________________________________________
Date: Feb 12, 2005
Subject: How do you carry the braid from a shielded wire past
the molex connector.
From: cecilth(at)juno.com
I need to carry the braid from a shielded wire past the molex connector. What is the correct way to do this? Just carry it through as one of the pins in the connector? Cecil ________________________________________________________________________________
Date: Feb 12, 2005
From: <chaztuna(at)adelphia.net>
Subject: Relays for heated pitot tube circuit question
was Size of Fuse vs. Circuit Breaker - Corrected > >Bob, > > > >What's you conclusion on the pitot heater example . . . what would the > >appropriate wire size be 14, 16 or 18? > > How big a pitot heater? They come in 100, 150 and 200 watt sizes > or more. How much wire does it take to wire up the pitot tube? If > you have a plastic airplane, remember that TOTAL path length includes > a return ground wire. If you want the 99.9% UNIVERSAL answer, you can > wire with 10AWG protected with a 30A fuse with a very high probability > of satisfactory operation. Recall that fuses/breakers protect wire, > wire needs to be of sufficient size that voltage drops and temperature > rises are tolerable. So, wiring up with some configuration that > many folks would consider overkill, it is not incorrect. Voltage > drops and temperature rises will be very acceptable and the wire > run is adequately protected. If you went with the 14AWG/30A > example I cited earlier, you're going to have a 99.0 or > better probability of success. > > Cookbook wiring philosophies tend conservative and assume that > your selection of parts and operation of the airplane is not > out of the ordinary. As a designer, I make it a goal to understand > the performance characteristics of all the parts so that the > installation is well considered and not overly heavy or expensive. > My decisions can affect the condition of hundreds of airplanes > over decades of future usage. You're only building one airplane > so the total impact of the conservative solution is measured > at worst in a few dollars and a pound or two. > > The vast majority of OBAM aircraft builders are doing this > because they desire the performance and maintenance alternatives > to over-regulated, technically-stagnated commercial products. > Most builders are installing Van's or Tony B's suggestions > that duplicate what's sold out of the spam can factories. > They will probably be perfectly happy with their decision. > > I presume folks on this list server are interested in looking > beyond the "norm" to consider ideas that my compatriots in > the certified side can only dream about. Forgive me if this > isn't the answer you were looking for but please understand > that I can't give you the considered answer without having > more data about the parts you've selected and the machine you're > building. I'll suggest further that after you've gathered > all the information needed, you'll be 95% of the way > to a goal of answering the question yourself. The discovery > process of gathering data is always the most time consuming. > Analysis of the discoveries for the purpose of fine-tuning > a design is simple. > > Bob . . . Bob, I have a Piper style heated 12 volt pitot. This unit has 2 heating elements. Each element draws 5 amps and has 16 AWG leads to each element. I would like to a 2-2 style switch to control the heater. Each heater element would have it's own fused circuit running 16AWG wire. Your previous advice has been that relays are not needed to protect the switch when current draw does not exceed 5 amps. Since this double pole switch will limit warmed up current to 5 amps per set of contacts in the switch, will this be sufficient? Will the high "in rush" current overwhelm the contacts in my Carling Technologies switch? Do I need the added complexity of relays? Would 14 AWG wire be needed or preferable? Charlie Kuss RV-8A cockpit wiring ________________________________________________________________________________
Date: Feb 12, 2005
From: Ken <klehman(at)albedo.net>
Subject: Re: Advice about 24V systems
If I may be so bold - A pound of battery is a pound of battery and it is silly to suggest that there is more energy or safety margin in arranging it into 24 volts rather than 12 volts. Your 12 volt accessories will drain just as much energy as 24 volt accessories for all practical purposes. IMO there is however a real safety margin advantage to sticking with tried and proven 12 volt components such as supplied for use with the stock 912S. THere is more discussion on this in the archives. Ken Nigel Harrison wrote: > > >Dear All, >I am a Europa builder and am planning to install an all-electric set up with >a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring, >he is of the opinion that a 24V electrical system will provide much more >safety margin tha a 12V system in the event of generator failure. My >aircraft will have a Rotax 912S. The engine manufacturers have advised me >that "Unfortunately the Rotax electrical system is only 12 V DC.The internal >alternator gives an AC voltage above 24 V at a speed of about 3000 rpm, >which may possibly be suitable, but you would have to design or procure a >rectifier/regulator for 24 V." Can someone advise me whether this alternator >would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series. >Rotax also mention a rectifier/regulator. Advice on this too would be >useful. > >I have little in the way of electrical knowledge/knowhow, so simple >explanations would be most helpful. > >Thanks > >Nigel Harrison > > ________________________________________________________________________________
Date: Feb 12, 2005
From: Mike Nellis <mike(at)bmnellis.com>
Subject: Re: Size of Fuse vs. Circuit Breaker - Corrected
Bob, A few years ago I tested the 5814 pitot/static tube which is basically the same as the one you have. You can see the graphed results here http://www.bmnellis.com/pitotcurrent.htm along with raw data link in the middle of the page. -- Mike Nellis Austin, TX CMRA #32 Honda RC51 '00 YZ426F '97 YZF1000 RV6 (Fuselage) '47 Stinson 108-2(Sold) http://bmnellis.com Bob C. wrote: > >Bob, > >The reason I asked . . . I'm building a RV-8 that was partially >completed by another builder . . . he had installed a Gretz Aero >AN5812 heated pitot. The installation instruction say it will draw >from 6.4 to 8.0 amps which would put it in the 100W range. The >predecessor builder had run 16AGW from the pitot to the wing root . . >. > >I was planning on finishing the circuit with 16 and putting a 10A >switch/breaker in to feed this device. Sounds like it "could be" a >little light on start up? > >I learn a lot from this list!? > >Thanks, >Bob Christensen > > > wrote: > > Corrected >> >> >> >> >>> >>>Bob, >>> >>>What's you conclusion on the pitot heater example . . . what would the >>>appropriate wire size be 14, 16 or 18? >>> >>> >> How big a pitot heater? They come in 100, 150 and 200 watt sizes >> or more. How much wire does it take to wire up the pitot tube? If >> you have a plastic airplane, remember that TOTAL path length includes >> a return ground wire. If you want the 99.9% UNIVERSAL answer, you can >> wire with 10AWG protected with a 30A fuse with a very high probability >> of satisfactory operation. Recall that fuses/breakers protect wire, >> wire needs to be of sufficient size that voltage drops and temperature >> rises are tolerable. So, wiring up with some configuration that >> many folks would consider overkill, it is not incorrect. Voltage >> drops and temperature rises will be very acceptable and the wire >> run is adequately protected. If you went with the 14AWG/30A >> example I cited earlier, you're going to have a 99.0 or >> better probability of success. >> >> Cookbook wiring philosophies tend conservative and assume that >> your selection of parts and operation of the airplane is not >> out of the ordinary. As a designer, I make it a goal to understand >> the performance characteristics of all the parts so that the >> installation is well considered and not overly heavy or expensive. >> My decisions can affect the condition of hundreds of airplanes >> over decades of future usage. You're only building one airplane >> so the total impact of the conservative solution is measured >> at worst in a few dollars and a pound or two. >> >> The vast majority of OBAM aircraft builders are doing this >> because they desire the performance and maintenance alternatives >> to over-regulated, technically-stagnated commercial products. >> Most builders are installing Van's or Tony B's suggestions >> that duplicate what's sold out of the spam can factories. >> They will probably be perfectly happy with their decision. >> >> I presume folks on this list server are interested in looking >> beyond the "norm" to consider ideas that my compatriots in >> the certified side can only dream about. Forgive me if this >> isn't the answer you were looking for but please understand >> that I can't give you the considered answer without having >> more data about the parts you've selected and the machine you're >> building. I'll suggest further that after you've gathered >> all the information needed, you'll be 95% of the way >> to a goal of answering the question yourself. The discovery >> process of gathering data is always the most time consuming. >> Analysis of the discoveries for the purpose of fine-tuning >> a design is simple. >> >> Bob . . . >> >> >> >> >> >> > > > > ________________________________________________________________________________
Date: Feb 12, 2005
From: Charlie England <ceengland(at)bellsouth.net>
Subject: Re: Pitot Tubes
Eric M. Jones wrote: > >Pitot tubes use a huge amount of power. The last time this matter seems to >have been studied in small aircraft at subsonic speeds >was....ah....1928...and they determined that Pitot tubes along with >wing-wires can collect ice! There is so little information online about the >subject that a Google search of heated pitot tubes come up with "Do you >mean...Heated Pilot tubes"? Now there's an image....Hey Bob, I think I feel >some rain. > >Could you build a Pitot tube that remained ice-free and had no >heater---Certainly. It's not even very hard. >Could you spritz Miracle-Spray on the tube to stave off ice >accumulation?---Certainly. >Could you use an iced Pitot tube to tell you to get the heck out of there >'cause you aren't delivering the anti-toxin?---Oh man....Yes. >Could you use slip a sock over the metal tube to conserve warmth and turn >down the current? Why not. > >I have a little write-up on my own thermostatic heated pitot tube which I >can immodestly claim is light years ahead of AN5812. See >http://www.periheliondesign.com/downloads.htm > >Imagine what a Pitot tube actually does--It keeps a tiny little space warm >enough to keep a hole open and ice-free in the direction of flight. The >surrounding air cools it off and it reaches some temperature equilibrium >determined by the heater and cooling by the air flow. > >Could you build a Pitot tube that remained ice-free and had no >heater---Certainly. It's not even very hard. >Could you spritz Miracle-Spray on the tube to stave off ice >accumulation?---Certainly. >Could you use an iced Pitot tube to tell you to get the heck out of there >'cause you aren't delivering the anti-toxin?---Oh man....Yes. >Could you use slip a sock over the metal tube to conserve warmth and turn >down the current? Why not? >Could you put a current regulator into the circuit and only crank it up if >needed? Sure! > >More than most other aircraft parts, Pitot tube design is dragged down by >the rules and regulations. But if you don't have to use the old dog-leg, >bring it up to modern times. > >Regards, >Eric M. Jones >www.PerihelionDesign.com >113 Brentwood Drive >Southbridge MA 01550-2705 >Phone (508) 764-2072 >Email: emjones(at)charter.net > Or you could do what Rutan did on one of his unmarketed designs (maybe the Catbird?) & make the pitot a little bump on top of the wing near the trailing edge. A friend plumbed a 2nd airspeed indicator to the back engine baffle in his RV-6A; it always agreed exactly with his primary ASI. No heat in either case. FWIW, YMMV, ETC, ETC Charlie ________________________________________________________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: Re: How do you carry the braid from a shielded wire
Date: Feb 12, 2005
>I need to carry the braid from a shielded wire past the molex connector. >What is the correct way to do this? >Just carry it through as one of the pins in the connector? >Cecil Okay so I had a triple espresso........ Almost nobody does shield termination correctly. Allow me to explain: A shield-- braid, tape or foil is a kind of perfect partner--a little Faraday cage around the wires that acts as a ground plane in reference to the wires running through it. When some charge moves on the internal wires, the shield supplies the opposite charge--on loan from ground. Well sort of...... The right way of terminating the shield is coaxially--like a coaxial bulkhead connector does. The absolutely wrong way is to separate the inner wires from the shield and twist the shield into a wire and attach it to ground as if it were just another wire. Holy Moley! Now that you have strangled the little baby shield it develops a bad case of impedance at frequencies that otherwise would have been grounded--depending on the fine and random details of the high impedance "pigtail". This makes terminating a shield a task that calls for special care. A way to understand how to do this properly is to imagine a grounded metal wall that the wire goes through. The shield is teased open and electrically bonded to the wall around the circumference of the hole. That's the way to do it. Any technique that approximates this is better than a "pigtail" Oink, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net "I thoroughly disapprove of duels. If a man should challenge me, I would take him kindly and forgivingly by the hand and lead him to a quiet place and kill him." -- Mark Twain ________________________________________________________________________________
Date: Feb 12, 2005
From: "Bob C. " <flyboy.bob(at)gmail.com>
Subject: Re: How do you carry the braid from a shielded wire
past the molex connector. That's what I would do . . . I don't see how that would be a problem?! > > I need to carry the braid from a shielded wire past the molex connector. > What is the correct way to do this? > Just carry it through as one of the pins in the connector? > Cecil > > > ________________________________________________________________________________
From: "Dean" <dvanwinkle(at)royell.net>
Subject: Re: Wing wiring grounds
Date: Feb 12, 2005
John and Jay The best way to insure a good structural ground is by use of abrasive bonding brushes to remove the primer and any anodize coating. I obtained mine from The Yard in Wichita. A 4 piece set, P/N 14706, is $3.95 in the current catalog. They have a 1/4 inch shaft and 3/32, 1/8, 5/32, and 3/16 pilots. They have a much more expensive set that is more suited to avionics shop or production line use. Try 1-800-888-8991 or www.yardstore.com. Finish with an appropriate ring terminal, bolt, and locknut. Dean Van Winkle RV-9A Fuselage/Finish ----- Original Message ----- From: "John Schroeder" <jschroeder(at)perigee.net> Subject: Re: AeroElectric-List: Wing wiring grounds > > Jay - > > Check the archives. Bob has answered this several times. As I recall, it > is OK to do this for these systems, but I'd check for sure. > > John > > > > I'm building an RV and priming... Perhaps this question is obvious to > > some, but not to me. Is it good practice to ground landing lights, > > heated pitot and > > position lights to the airframe or are return wires required for each? If > > airframe ground is okay then how does one do that to insure safe and > > secure contact? > > ________________________________________________________________________________
From: "Wayne Sweet" <w_sweet(at)comcast.net>
Subject: Re: How do you carry the braid from a shielded
wire
Date: Feb 12, 2005
Don't quite get the picture. Is this equivalent; bare the shield around the circumference, letting it retain it's structure and form, then soldering a bare wire around that shield's circumference and taking that wire to the ground lug? Wayne ----- Original Message ----- From: "Eric M. Jones" <emjones(at)charter.net> Subject: AeroElectric-List: Re: How do you carry the braid from a shielded wire > > > >>I need to carry the braid from a shielded wire past the molex connector. >>What is the correct way to do this? >>Just carry it through as one of the pins in the connector? >>Cecil > > Okay so I had a triple espresso........ > > Almost nobody does shield termination correctly. Allow me to explain: > > A shield-- braid, tape or foil is a kind of perfect partner--a little > Faraday cage around the wires that acts as a ground plane in reference to > the wires running through it. When some charge moves on the internal > wires, > the shield supplies the opposite charge--on loan from ground. Well sort > of...... > > The right way of terminating the shield is coaxially--like a coaxial > bulkhead connector does. The absolutely wrong way is to separate the inner > wires from the shield and twist the shield into a wire and attach it to > ground as if it were just another wire. Holy Moley! Now that you have > strangled the little baby shield it develops a bad case of impedance at > frequencies that otherwise would have been grounded--depending on the fine > and random details of the high impedance "pigtail". > > This makes terminating a shield a task that calls for special care. A way > to > understand how to do this properly is to imagine a grounded metal wall > that > the wire goes through. The shield is teased open and electrically bonded > to > the wall around the circumference of the hole. That's the way to do it. > Any > technique that approximates this is better than a "pigtail" > > Oink, > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge MA 01550-2705 > Phone (508) 764-2072 > Email: emjones(at)charter.net > > "I thoroughly disapprove of duels. If a man should challenge me, I would > take him kindly and forgivingly by the hand and lead him to a quiet place > and kill him." -- Mark Twain > > > Try www.SPAMfighter.com for free now! ________________________________________________________________________________
Date: Feb 12, 2005
From: Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com>
Subject: Coax crimper / stripper question
Would this tool crimp RG-142/400? Perhaps -400 is size equivalent to others? If so, which size? http://www.mytoolstore.com/klein/t1720.html Also, would someone be so kind as to recommend a good coax stripper? Thanks! Jay ===== __________________________________ http://info.mail.yahoo.com/mail_250 ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Advice about 24V systems
> > > >Dear All, >I am a Europa builder and am planning to install an all-electric set up with >a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring, >he is of the opinion that a 24V electrical system will provide much more >safety margin tha a 12V system in the event of generator failure. With all due respect to Greg's accomplishments as a manufacturer of EFIS systems, the article you cited is rife with errors and offers no understanding of the simple-ideas in physics that support good design decisions. If you're interested in the details you can check out: http://aeroelectric.com/articles/richter/richter.html >My aircraft will have a Rotax 912S. The engine manufacturers have advised me >that "Unfortunately the Rotax electrical system is only 12 V DC.The internal >alternator gives an AC voltage above 24 V at a speed of about 3000 rpm, >which may possibly be suitable, but you would have to design or procure a >rectifier/regulator for 24 V." Can someone advise me whether this alternator >would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series. >Rotax also mention a rectifier/regulator. Advice on this too would be >useful. I aware of no compelling explanation of system operation and design that makes a case for 24 volt systems replacing 12 volt systems in small aircraft. The owner built and maintained aircraft industry is seeking best return on investment (i.e. VALUE) for component selection and system architecture. The automotive world provides us with many low cost, robust alternatives to 24 volt devices which are uniquely aircraft in nature. The high cost of certification and relatively low production numbers makes aircraft parts a very poor value. >I have little in the way of electrical knowledge/knowhow, so simple >explanations would be most helpful. May I suggest a source of information on a variety of small aircraft electrical systems topics? Look over the offerings at: http://aeroelectric.com/articles.html Further, please stay with us here on the AeroElectric-List. There are many folks among the 1300+ subscribers who will be pleased to share their experiences and insight as they apply to your task. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> shielded wire past the molex
connector.
Subject: Re: How do you carry the braid from a
shielded wire past the molex connector. shielded wire past the molex connector. > > >I need to carry the braid from a shielded wire past the molex connector. >What is the correct way to do this? >Just carry it through as one of the pins in the connector? This is what's usually done. Since you're talking about "molex" connectors, are you working with the shielded wire in a strobe system? Also see: http://aeroelectric.com/articles/pigtail/pigtail.html This shows how to deal with multiple shielded wires in a bundle. Bob . . . ________________________________________________________________________________
From: "Tinne maha" <tinnemaha(at)hotmail.com>
Subject: LSE Ign Power Wire
Date: Feb 12, 2005
I installed a single LSE ignition in my project a while back and, for some unknown reason, ran an AWG 14 wire from the battery bus to the control module. Two hours ago, I'd have sworn up & down that the installation manual required that big of a wire, but now I can't find any reference to it in the manual or on the web page. The web page shows a current draw of 1.2 amps @ 13.8 volts for my Plasma II/4 cylinder set up: This would only require an AWG 20 or so wire. Will listers with operating LSE systems please tell me if I'm cracking up? How did you size the power wire on your project? Thanks, Grant ________________________________________________________________________________
From: "Tinne maha" <tinnemaha(at)hotmail.com>
Subject: Taxi/Landing Lights
Date: Feb 12, 2005
Bob/List, I finally found the time/equipment/etc. needed to measure the current used by my taxi & landing lights. 4.4 amps each. Thanks for your suggestions on that. The measurement may not have been necessary, but I couldn't calculate theoretical values 'cuz I didn't have any data: 'Sides that, I'm a 'seeing is believing' kinda guy & it was a good exercise for me. Satisfied my curiosity. Now the question becomes how to wire these two lights (together in one housing, but able to be controlled separately) for optimum use. I'm inclined to set it up with a 3 position switch - down is 'Off', middle is taxi light only & up is both landing & taxi lights on. I've thought of other possble set ups (2 separate, 'on-off' switches or a 3 position switch that doesn't allow both lights to be on at the same time), but I can't think of a reason NOT to have the taxi light on whenever the landing light is on. The only difference between the two lights, as far as I can tell, is the angle at which the light is directed. Any comments, sugestions or criticisms would be appreciated. Thank You Again, Grant Krueger ________________________________________________________________________________
From: "Nigel Harrison" <naharrison(at)manx.net>
Subject: Advice about 24V systems
Date: Feb 13, 2005
Thank you Bob for your thoughts and recommendations. I will stay with aeroelectric. I've ordered the aeroelectric book too. It looks as if I would be best to go for 12 V with the addition of a second battery as a back up. Am I correct in thinking that if they were connected in parallel this would allow the generator to charge both? Some sort of switching mechanism could then allow the back up to be used once the main battery power was used up. Best wishes Nigel Harrison Isle of Man -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: Re: AeroElectric-List: Advice about 24V systems > > > >Dear All, >I am a Europa builder and am planning to install an all-electric set up with >a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring, >he is of the opinion that a 24V electrical system will provide much more >safety margin tha a 12V system in the event of generator failure. With all due respect to Greg's accomplishments as a manufacturer of EFIS systems, the article you cited is rife with errors and offers no understanding of the simple-ideas in physics that support good design decisions. If you're interested in the details you can check out: http://aeroelectric.com/articles/richter/richter.html >My aircraft will have a Rotax 912S. The engine manufacturers have advised me >that "Unfortunately the Rotax electrical system is only 12 V DC.The internal >alternator gives an AC voltage above 24 V at a speed of about 3000 rpm, >which may possibly be suitable, but you would have to design or procure a >rectifier/regulator for 24 V." Can someone advise me whether this alternator >would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series. >Rotax also mention a rectifier/regulator. Advice on this too would be >useful. I aware of no compelling explanation of system operation and design that makes a case for 24 volt systems replacing 12 volt systems in small aircraft. The owner built and maintained aircraft industry is seeking best return on investment (i.e. VALUE) for component selection and system architecture. The automotive world provides us with many low cost, robust alternatives to 24 volt devices which are uniquely aircraft in nature. The high cost of certification and relatively low production numbers makes aircraft parts a very poor value. >I have little in the way of electrical knowledge/knowhow, so simple >explanations would be most helpful. May I suggest a source of information on a variety of small aircraft electrical systems topics? Look over the offerings at: http://aeroelectric.com/articles.html Further, please stay with us here on the AeroElectric-List. There are many folks among the 1300+ subscribers who will be pleased to share their experiences and insight as they apply to your task. Bob . . . ************************************************************* This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus ************************************************************* ************************************************************* This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus ************************************************************* ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Coax crimper / stripper question
> > >Would this tool crimp RG-142/400? Perhaps -400 is size equivalent to >others? If >so, which size? > >http://www.mytoolstore.com/klein/t1720.html This tool doesn't have the proper die sizes. You need a .213" hex and .068 round or hex for most connectors used on RG142/400. See BNC Crip tool at: http://bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?9X358218#RCT-2 >Also, would someone be so kind as to recommend a good coax stripper? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4693&item=5751327980&rd=1 This tool says RG-59/6 but the three blades are individually adjustable for cut depth and it's easily set up for RG-142/400 Bob . . . -------------------------------------------------------- < Throughout history, poverty is the normal condition > < of man. Advances which permit this norm to be > < exceeded -- here and there, now and then -- are the > < work of an extremely small minority, frequently > < despised, often condemned, and almost always opposed > < by all right-thinking people. Whenever this tiny > < minority is kept from creating, or (as sometimes > < happens) is driven out of a society, the people > < then slip back into abject poverty. > < > < This is known as "bad luck". > < -Lazarus Long- > <------------------------------------------------------> http://www.aeroelectric.com ________________________________________________________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: Re: How do you carry the braid from a shielded
Date: Feb 13, 2005
>Don't quite get the picture. Is this equivalent; bare the shield around the >circumference, letting it retain it's structure and form, then soldering a >bare wire around that shield's circumference and taking that wire to the >ground lug? >Wayne Wayne, That's a negative. Bob's published way is also....ahem....problematic. The right way of running a shield through a D-Sub is with a shield--not a pigtail. The problem can be summarized as follows (and what I say goes for higher frequencies, not DC): 1) The shield does what it does because of its geometry. Changing its geometry changes its response to charges in motion. There is a very big word to describe this but if I told you.....well....you know! 2) Changing the impedance by pigtailing the carefully-constructed coaxial shield wrecks the impedance and adds a spurious antenna at frequencies described by the particulars of the pigtail. 3) Taking care to make the coax think it's still a coax takes special care. 4) Little of this was common practice before 1980, due somewhat to the introduction of higher frequencies but moreover DIGITAL stuff since then. The EMC approvals that became required simply changed common practices. From Kimmel Gerke (EMC) Associates---"....all penetrations, such as shields or cables, be bonded or decoupled at the point of penetration...NO PIGTAILS or long leads. This is a leading cause of FCC/VDE failures, with poorly terminated wiring acting as undesired antennas." "Cables and Connectors....metal connectors with a full circumferential termination of cable shield to connector for any cable shield that must work above 1 MHz...NO PIGTAILS." (Emphasis mine) The connection of conductors is barely taught in electronics classes, but consider--- What's the difference between a 10A connector and a 100A, 1000A, or a million-Amp connector? What's the difference between a DC connector and a 10 MHz connector? What's the difference between a microvolt connector and a Megavolt connector? What's the difference between a gold connector and an aluminum connector? Well...so is there a difference between a coaxial connector and a pigtail? Does it matter? Maybe not. Do you have an aircraft that barely has any electronics and rarely strays far from the home field or rack full of stuff? Would like the best quality signals you can get? Do you want radio signals in that long dark patch between Bandahatchie and Huatabampo? Do you want to ask the Aeroelectric list how to quiet all the hums and buzzes in your intercom? As for the right way to terminate shielded wire---there are a myriad of ways. Check AMP "Braid-Pic" terminations. Or just browse thru Digikey section A. Or conceptually--imagine a fat ring-tongue connector. The shield goes into the sleeve and is soldered there. The center conductor is not teased out. This is not perfect but is way better than a pigtail. And there is still a lot to be said for a good twisted pair below a few GHz. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net Teamwork: " A lot of people doing exactly what I say." (Marketing exec., Citrix Corp.) ________________________________________________________________________________
Date: Feb 13, 2005
Subject: Re: LSE Ign Power Wire
From: "Matt Prather" <mprather(at)spro.net>
I used 18g in my Varieze - partly because the run from the nose (battery location) to the firewall (ign module location) is kind of long. Regards, Matt- VE N34RD > > > I installed a single LSE ignition in my project a while back and, for > some unknown reason, ran an AWG 14 wire from the battery bus to the > control module. Two hours ago, I'd have sworn up & down that the > installation manual required that big of a wire, but now I can't find > any reference to it in the manual or on the web page. > > The web page shows a current draw of 1.2 amps @ 13.8 volts for my Plasma > II/4 cylinder set up: This would only require an AWG 20 or so wire. > > Will listers with operating LSE systems please tell me if I'm cracking > up? How did you size the power wire on your project? > > Thanks, > Grant > > ________________________________________________________________________________
From: "cgalley" <cgalley(at)qcbc.org>
Subject: Re: Coax crimper / stripper question
Date: Feb 13, 2005
I have a Model 59500 Amp crimper but no dies. Where can anyone find just the dies at a reasonable cost? Cy Galley - Bellanca Champion Club Newsletter Editor-in-Chief & EAA TC www.bellanca-championclub.com Actively supporting Bellancas every day ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Taxi/Landing Lights
> >Bob/List, > >I finally found the time/equipment/etc. needed to measure the current used >by my taxi & landing lights. 4.4 amps each. Thanks for your suggestions on >that. The measurement may not have been necessary, but I couldn't calculate >theoretical values 'cuz I didn't have any data: 'Sides that, I'm a 'seeing >is believing' kinda guy & it was a good exercise for me. Satisfied my >curiosity. Good for you! >Now the question becomes how to wire these two lights (together in one >housing, but able to be controlled separately) for optimum use. I'm >inclined to set it up with a 3 position switch - down is 'Off', middle is >taxi light only & up is both landing & taxi lights on. I've thought of >other possble set ups (2 separate, 'on-off' switches or a 3 position switch >that doesn't allow both lights to be on at the same time), but I can't think >of a reason NOT to have the taxi light on whenever the landing light is on. >The only difference between the two lights, as far as I can tell, is the >angle at which the light is directed. This is a common feature on OBAM aircraft. A signle S700-2-10 or equal is wired per Figure 11-17 in the 'Connection to function just as you've described. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Advice about 24V systems
> > > >Thank you Bob for your thoughts and recommendations. I will stay with >aeroelectric. I've ordered the aeroelectric book too. It looks as if I would >be best to go for 12 V with the addition of a second battery as a back up. What is it that you want to "back up"? Most aircraft with a 912 engine are relatively simple. What systems do you plan to carry and what flight operations do you anticipate that demand extra-ordinary power supply reliability? >Am I correct in thinking that if they were connected in parallel this would >allow the generator to charge both? Some sort of switching mechanism could >then allow the back up to be used once the main battery power was used up. You can have as many batteries as you wish and run them in parallel for all normal operations. Active notification of low voltage heralds failure of an alternator whereupon the pilot separates each battery from the others to accomplish their respective tasks. Let's talk about the equipment you plan to carry, how much energy each system requires and how you plan to us the airplane. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: LSE Ign Power Wire
> >I installed a single LSE ignition in my project a while back and, for some >unknown reason, ran an AWG 14 wire from the battery bus to the control >module. Two hours ago, I'd have sworn up & down that the installation >manual required that big of a wire, but now I can't find any reference to it >in the manual or on the web page. > >The web page shows a current draw of 1.2 amps @ 13.8 volts for my Plasma >II/4 cylinder set up: This would only require an AWG 20 or so wire. > >Will listers with operating LSE systems please tell me if I'm cracking up? >How did you size the power wire on your project? 22AWG is electrically robust enough to do the task. Some manufacturers have a policy that no wiring on the engine for control or insrumentation is less than 20AWG for mechanical robustness . . . but there's no good reason I can deduce for 14AWG wire to feed this accessory. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com>
Subject: Re: AeroElectric-List Digest: 23 Msgs - 02/12/05
Am I out of luck? I trimmed by shielded wing strobe wires with the idea of running them to a connector at the wing root. What sort of connector to use? Can I splice or should I punt and run only a single wire run between power supply and strobe? (Wheelen only gives you one big hunk of wire...) Jay >I need to carry the braid from a shielded wire past the molex connector. >What is the correct way to do this? >Just carry it through as one of the pins in the connector? >Cecil Okay so I had a triple espresso........ Almost nobody does shield termination correctly. Allow me to explain: A shield-- braid, tape or foil is a kind of perfect partner--a little Faraday cage around the wires that acts as a ground plane in reference to the wires running through it. When some charge moves on the internal wires, the shield supplies the opposite charge--on loan from ground. Well sort of...... The right way of terminating the shield is coaxially--like a coaxial bulkhead connector does. The absolutely wrong way is to separate the inner wires from the shield and twist the shield into a wire and attach it to ground as if it were just another wire. Holy Moley! Now that you have strangled the little baby shield it develops a bad case of impedance at frequencies that otherwise would have been grounded--depending on the fine and random details of the high impedance "pigtail". This makes terminating a shield a task that calls for special care. A way to understand how to do this properly is to imagine a grounded metal wall that the wire goes through. The shield is teased open and electrically bonded to the wall around the circumference of the hole. That's the way to do it. Any technique that approximates this is better than a "pigtail" Oink, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net ===== __________________________________ http://my.yahoo.com ________________________________________________________________________________
From: N1deltawhiskey(at)aol.com
Date: Feb 13, 2005
Subject: Re: How do you carry the braid from a shielded
Eric, Interesting comments. Not necessarily an "infidel," but perhaps a slightly confused skeptic. Your comments for coax makes sense when it comes to low energy RF signals. And coax connectors are designed to do just as you suggest. Allowing that I may be wrong in my perspective/assumptions, the rest of the wiring in our aircrafts are carrying much lower frequency currents, so we use shielded wire where the impact of external electro-magnetic energy could set up unwanted currents in our wire, usually referred to as "noise" if it is at audio frequencies. Where it may be an issue, the unshielded part of our wire becomes sort of an antenna to pick up these stray EM fields. The shorter the unshielded wire, the less opportunity to pick up this EM energy. Where shielded, the EM may set up currents in our shield and shielded wire equally, but since the latter is grounded, the net effect is 0. So, I would deduce that the shorter the unshielded wire, the lower the currents that the EM can set up. While these are not 0, they may be low enough to not be audible. Hence, the pigtail solution. I looked at Bob's article and found it interesting he was using single conductor shielded for his demo. I have none of that in my A/C, they are all 2- or 3-conductor shielded, twisted internally. In this case, I should think the pigtail method would work fine in most cases. I also noted is was recommended for my Apollo GX-60/SL-70 interconnections with the caveat that the unshielded portion of the wire be as short as possible, and the pigtail no longer than 1-1/4". So these do, apparently, and usually, provide satisfactory performance. Not as quiet as concentric pass-throughs, but a lot better than unshielded. On the other hand, I have trouble imagining a pass-through using D-sub connectors that would be concentric. What you seem to suggest is that all shielded wires be connected using some other kind of connector. What do you have in mind that would allow us to do what you suggest? Regards, Doug Windhorn In a message dated 13-Feb-05 7:24:17 Pacific Standard Time, emjones(at)charter.net writes: >Don't quite get the picture. Is this equivalent; bare the shield around the >circumference, letting it retain it's structure and form, then soldering a >bare wire around that shield's circumference and taking that wire to the >ground lug? >Wayne Wayne, That's a negative. Bob's published way is also....ahem....problematic. The right way of running a shield through a D-Sub is with a shield--not a pigtail. The problem can be summarized as follows (and what I say goes for higher frequencies, not DC): 1) The shield does what it does because of its geometry. Changing its geometry changes its response to charges in motion. There is a very big word to describe this but if I told you.....well....you know! 2) Changing the impedance by pigtailing the carefully-constructed coaxial shield wrecks the impedance and adds a spurious antenna at frequencies described by the particulars of the pigtail. 3) Taking care to make the coax think it's still a coax takes special care. 4) Little of this was common practice before 1980, due somewhat to the introduction of higher frequencies but moreover DIGITAL stuff since then. The EMC approvals that became required simply changed common practices. From Kimmel Gerke (EMC) Associates---"....all penetrations, such as shields or cables, be bonded or decoupled at the point of penetration...NO PIGTAILS or long leads. This is a leading cause of FCC/VDE failures, with poorly terminated wiring acting as undesired antennas." "Cables and Connectors....metal connectors with a full circumferential termination of cable shield to connector for any cable shield that must work above 1 MHz...NO PIGTAILS." (Emphasis mine) The connection of conductors is barely taught in electronics classes, but consider--- What's the difference between a 10A connector and a 100A, 1000A, or a million-Amp connector? What's the difference between a DC connector and a 10 MHz connector? What's the difference between a microvolt connector and a Megavolt connector? What's the difference between a gold connector and an aluminum connector? Well...so is there a difference between a coaxial connector and a pigtail? Does it matter? Maybe not. Do you have an aircraft that barely has any electronics and rarely strays far from the home field or rack full of stuff? Would like the best quality signals you can get? Do you want radio signals in that long dark patch between Bandahatchie and Huatabampo? Do you want to ask the Aeroelectric list how to quiet all the hums and buzzes in your intercom? As for the right way to terminate shielded wire---there are a myriad of ways. Check AMP "Braid-Pic" terminations. Or just browse thru Digikey section A. Or conceptually--imagine a fat ring-tongue connector. The shield goes into the sleeve and is soldered there. The center conductor is not teased out. This is not perfect but is way better than a pigtail. And there is still a lot to be said for a good twisted pair below a few GHz. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net Teamwork: " A lot of people doing exactly what I say." (Marketing exec., Citrix Corp.) ________________________________________________________________________________
From: "Tinne maha" <tinnemaha(at)hotmail.com>
Subject: Light Switch
Date: Feb 13, 2005
Hello Bob/List, I've read Bob's shop notes about 'Switch Ratings, What's it all mean?', including Bob's conservative rule of thumb that the 115 Volt AC current rating stamped on most switches can be substituted for the 12 Volt DC current rating. Literature on the switch I hope/plan to use on my taxi/landing light gives a 4 Amp rating for 30 Volts DC. Does it follow that the same switch can carry 8 amps at 15 Volts DC? (BTW, the literature gives AC Ratings as follows: 3 amps @ 250 Volts, 6 amps @ 125 Volts. So, my question re-phrased is: Does this apparently linear relationship also apply to DC ratings?) Thanks in advance, Grant ________________________________________________________________________________
Date: Feb 13, 2005
Subject: Re: Coax crimper / stripper question
From: "John Schroeder" <jschroeder(at)perigee.net>
Jay - That tool seems to be a tad high priced for doing a very few crimps on an airplane. It also illustrates the variety of coax's there are and choosing the right tool makes it hard. Here is one way to decide which die set to buy for the coax work. Decide on the brand of connector: AMP, Amphenol, etc. ... . Amphenols cost more, but I have yet to run into any trouble using them. Another brand we used gave us trouble getting the ferrule down over the insulation and flush to the outer case of the BNC to crimp it. They were commercial grade from Digi-Key as I recall. The extension the goes between the insulated inner conductor and the shielding is a tad too fat. It was also hard to get the center connector/pin to snap into place. In the catalogs, go to the coax number you intend to use and get the mfg.'s product number. Then get the specs and it will tell you what size crimp for the center pin and for the ferrule. Then buy a die set for the crimper frame. This info should be available on line in the DigiKey and Mouser catalogs. For a stripper, Bob Nuckolls looked at this one and liked it a lot. We have a different one, but the important thing is that you can do all the cutting and stripping in one use of the tool, and when you adjust it right, it will not cut any ot the shield stranding or the center conductor. http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4693&item=5722575929 I bought a Paladin 1300 series ratcheting crimper frame and 2 sets of dies. One set (#2082) has a slot for 24-30 AWG open barrel and another for 18-22 AWG open barrel. This combo does Molex Mini-Fit Juniors, AMP CPC Type I, AMP Mate 'N Lock (the kind that Whelan sends along with their light and strobe kits) and the older Molex connectors. The other set of dies (no number) for the Paladin has slots for 22-18, 16-14 and 12-10 open barrels. I used this set to crimp a few AWG16 and a couple of AWG 12 wires to Molex Mini Fit Senior connectors (landing/taxi lights and pitot heat, respectively). The Paladin is a medium quality crimper and the dies are good quality. You will not wear them out on one airplane's wiring project. The frame and both sets of dies were $76. I bought them from GreatCables.com. You can also get a Paladin die set for crimping Red, Blue and Yellow PIDG terminals for another $22. The machined pin crimper from B&C is specially modified to do perfect crimps on the AMP brand machined pins. They set the depth so that the diamond crimp is at the right position on the pin. You do Dsubs and AMP CPC Type 2 CPC's with these pins and crimper. I have done about 80 percent of all crimps with these two crimpers and the 8082 die set for the Paladin. The wire range for these pins are AWG 20 to 24. We went to CPC Type 1's or Molex Mini Fit Juniors when we had AWG 18 wires to put into connectors along with AWG 20 & 22 wires. In one particular Type 1, we had AWG 18's, 20's 22's and a couple of 16's and 14's. But, remember they take different size open barrel pins hence we used both dies sets. One lesson we learned is: Dsubs are great for computers, but hard to hook up when joining two cables. They mate OK, but securing them with those 4-40 screws and hex standoff nuts is a pain in cramped places (that's damn near everywhere in an airplane). We converted several of ours to AMP CPC Type 2's and the machined pins. Much easier to mate and lock to each other. You use the same pin extractor and crimper for both DSubs and CPC Type 2's. The other connector we used a lot of were the AMP Mini-Fit Juniors. They carry more amps than a DSub (up to 9), are nice to crimp and lock together easily. They make a pin for this connector that is very easy to crimp to those beastly thin wires that RAy Allen (MAC) uses on their trim servo components. We also used several AMP CPC Type 1's. Steinair also sells a frame and some dies, a machined pin crimper and the machined pins & sockets. I don't know what brand they are or the size of the dies. And I have not used them. This was a long answer to your question, but I hope it helps in other aspects of the wiring. Cheers, John > Would this tool crimp RG-142/400? Perhaps -400 is size equivalent to > others? If so, which size? > > http://www.mytoolstore.com/klein/t1720.html > > Also, would someone be so kind as to recommend a good coax stripper? ________________________________________________________________________________
From: "Eric M. Jones" <emjones(at)charter.net>
Subject: Re: How do you carry the braid from a shielded
Date: Feb 13, 2005
>Your comments for coax makes sense when it comes to low energy RF signals. >And coax connectors are designed to do just as you suggest. >Not as quiet as concentric pass-throughs, but a lot better than unshielded. >On the other hand, I have trouble imagining a pass-through using D-sub >connectors that would be concentric. What you seem to suggest is that all shielded >wires be connected using some other kind of connector. What do you have in >mind that would allow us to do what you suggest? >Regards, Doug Windhorn Hi Doug, The issue of what power levels and what frequencies require proper connections is fraught with peril. You might think that audio frequencies are easy, but a square wave is made up of ALL frequencies. (Fourier Series: Signals can be composed by a superposition of an infinite number of sine and cosine functions. The coefficients of the superposition depend on the signal being represented and are equivalent to knowing the function itself.....I bet you already knew that!) All D-sub connectors have matching covers to which the shield may be grounded. I would not be going very far out on the limb to say that all coaxial and common shielded cables have matching connectors. There are of course ungrounded shields--but you can get pretty much anything--so there's no accounting for taste. My description of how coaxial cable and shielded cable should be terminated would be helped by illustrations--none of which I have. But I assure you that this has been the standard technique since the 1980's. I expect many builders to say, "Well...it's good enough." This is my second favorite invitation to disaster right after, "Watch this...Hold my beer." Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones(at)charter.net "...as we know, there are known-knowns; there are things we know we know. We also know there are known-unknowns; that is to say, we know there are some things we do not know. But there are also unknown-unknowns; the ones we don't know we don't know." Donald Rumsfeld ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: 11937 Besing
>Below is the result of your inquiry. It was submitted by >Paul Besing (paul(at)kitlog.com) on Sunday, February 13, 2005 at 07:21:13 > >Sunday, February 13, 2005 > >Paul Besing > >, >Email: paul(at)kitlog.com >Comments/Questions: Bob, what are your thoughts on static wicks? There >has been some debate on an RV-10 list about them. Knowing your thoughts >on how much more reliable radios are nowadaws, I'm surprised to hear so >many people that want to now put them on airplanes. Static wicks have nothing to do with radio quality or reliability. EVERY time dissimilar materials slide across each other, there is a tendency for one material with a stronger affinity for electrons than the other to acquire a negative charge. Common manifestations include sparks that jump between fingertip and doorknob after walking across carpet. In the winter especially, I have to remind myself to keep part of my body touching the frame of my 1" vertical belt stander while sculpting a piece of metal . . . the Van DeGraff like nature of the belt sander will charge the ol' bod with a significant kick if I don't bleed it off during the sanding operations. Precipitation static is unique to airborne particles sliding past any conductor. Radio receivers can be severely affected by dust storms usually associated with high winds. I used to work with an amateur radio repeater installation 1200 feet up on KTVH-TV in Hutchinson, KS. A blowing snow storm would severely de-sense our receivers. Airplanes have unique problems in that they generate their own wind. Airplanes flying through dust, rain or snow can pick up significant charges. When the charge reaches sufficient magnitude, it begins to form coronas at the sharp (usually trailing edges) of wings and flight control surfaces. The static wick is a sharp-ended conductor (enhances tendency for charge to concentrate and form corona) connected to the airframe through some nominal but rather high resistance. The idea is to put sufficient static wicks in the right places so that they force lots of small, low current discharges to form and dissipate the energy at much lower (read less noisy) levels than if the wicks were not present. The faster the airplane flies, the more likely it is to experience the effects of p-static. Further, the finish and skin materials have an influence on tendency to build and concentrate static charges. These effects are present and potentially troublesome irrespective of the vintage of radios carried aboard the airplane. VHF radios are less susceptible than HF or ADF receivers. Grounded antennas are quieter than isolated antennas. There are some modern digital signal processing techniques that can reduce the audible effects of p-static but ultimately, locally generated static noises will overwhelm a receiver looking for weaker signals. The number, style and placement of static wicks on our bizjets is as much an art as a science. We spent a great deal of $time$ selecting the right products and installations. Further, there's a comprehensive incoming inspection of static wicks . . . seems that a performance of a static wick is very sensitive to production variability. If your airplane suffers from the effects of p-static, it may take a lot of effort over a long period of time to deduce the optimum solution. Bob . . . ________________________________________________________________________________
From: "Tinne maha" <tinnemaha(at)hotmail.com>
Subject: Fuel Pressure Gauges
Date: Feb 13, 2005
Hello again list, I am hoping/planning to install an Ellison throttle body on my Lycoming O-235 powered Kitfox. I will have an electric boost pump for priming as well as for take-off and landing, but there is no engine driven pump. As planned, there will be only about 0.8 PSI of fuel pressure in the normal flight attitude (i.e. boost pump off). The Throttle body I plan to use requires a minimum 0.5 PSI of fuel pressure. Normally I would not be comfortable with this narrow a margin of error, but I will have the boost pump to use should the pressure drop and, more importantly, I know this has already been done on a nearly identical Kitfox/engine combination. The owner & the builder of that particular airplane each have encouraged me to install a fuel pressure gauge, but I'm not convinced it will add any benefit other than confirming my electric fuel pump is working (I think I can determine that with my ammeter during run-up.) My reasoning is as follows: As a 0-10 PSI gauge is the lowest range I can find, the 'normal' reading for my plane will only be 10% of the range. Thus, any change in the normal condition will almost certainly be un-detectable unless it's already too late (e.g. engine roughness or fuel starvation set in.) Any experience, comments or criticisms on this? Thanks again, Grant Krueger ________________________________________________________________________________
From: Denis Walsh <denis.walsh(at)comcast.net>
Subject: Re: Fuel Pressure Gauges
Date: Feb 13, 2005
I use my direct reading psi gage for a couple other things. When it dances, it shows you are getting bubbles and about to get vapor lock. Nice to make sure it is steady before take off. Also when it reads high after a burger stop it means you have vapors building up and require hot start procedures. Lastly, when it drops to zero in flight it is a clear sign to change tanks before the motor quits. I agree with putting one in, but it does not seem absolutely necessary to me either. Hope this helps. Denis (non mechanic, non expert, non kitfox, and non 235 owner) On Feb 13, 2005, at 4:03 PM, Tinne maha wrote: > > > Hello again list, > > I am hoping/planning to install an Ellison throttle body on my Lycoming > O-235 powered Kitfox. I will have an electric boost pump for priming > as > well as for take-off and landing, but there is no engine driven pump. > As > planned, there will be only about 0.8 PSI of fuel pressure in the > normal > flight attitude (i.e. boost pump off). The Throttle body I plan to use > requires a minimum 0.5 PSI of fuel pressure. Normally I would not be > comfortable with this narrow a margin of error, but I will have the > boost > pump to use should the pressure drop and, more importantly, I know > this has > already been done on a nearly identical Kitfox/engine combination. > > The owner & the builder of that particular airplane each have > encouraged me > to install a fuel pressure gauge, but I'm not convinced it will add any > benefit other than confirming my electric fuel pump is working (I > think I > can determine that with my ammeter during run-up.) My reasoning is as > follows: As a 0-10 PSI gauge is the lowest range I can find, the > 'normal' > reading for my plane will only be 10% of the range. Thus, any change > in the > normal condition will almost certainly be un-detectable unless it's > already > too late (e.g. engine roughness or fuel starvation set in.) > > Any experience, comments or criticisms on this? > > Thanks again, > Grant Krueger > > ________________________________________________________________________________
From: "F. ILMAIN" <f_ilmain(at)hotmail.com>
Subject: Garmin Antenna
Date: Feb 14, 2005
Does anyone knows if a Garmin GPS antenna can be used with 2 receivers (a pannel mount and a handheld for example) with a split coax cable Thanks ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Re: static wicks
>As always, your responses are detailed and helpful. Thanks again for taking >the time to respond. I gather from your response, that for the experimental >airplane, randomly installing static wicks on control surfaces probably >wouldn't do as much benefit? Just no way to tell. You have to start some place. The BIG problem with deducing static wick effectiveness is quantification. It's nearly impossible to duplicate both conditions that produce the noise and very difficult to gage magnitude of the noise. I'll ask around out at RAC and see if I can get some first hand guidance from folks who have done this. In any case, if you've had a problem at some point in time it certainly doesn't hurt to try SOMETHING. It may be "pink elephant" repellant (haven't seen any pink elephants around here in a long time . . . it must be working!), or it may just do the trick. The hard part is knowing when you've truly done a good thing. Fortunately, our customers fly around in p-static territory with some regularity . . . we get feedback pretty fast. If I were to task you with a development program to optimize the wicks installation on an RV, just how would you go about it? Let me see what the pros have to say. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Light Switch
> >Hello Bob/List, > >I've read Bob's shop notes about 'Switch Ratings, What's it all mean?', >including Bob's conservative rule of thumb that the 115 Volt AC current >rating stamped on most switches can be substituted for the 12 Volt DC >current rating. > >Literature on the switch I hope/plan to use on my taxi/landing light gives a >4 Amp rating for 30 Volts DC. Does it follow that the same switch can carry >8 amps at 15 Volts DC? > >(BTW, the literature gives AC Ratings as follows: 3 amps @ 250 Volts, 6 amps >@ 125 Volts. So, my question re-phrased is: Does this apparently linear >relationship also apply to DC ratings?) No . . . it's not linear. If the switch is 6A at 125 it will perform well at 6A and 14v as well. By "well" I mean thousands of cycles. Most switches are rated in tens of thousands of cycles at full ratings, some as high as 50,000 cycles. Suppose DOUBLING the current through the switch cuts your rating by 90%, how long will it take to put 1,000-5,000 cycles on any switch in your airplane? Use whatever switch you like and don't loose any sleep over it. The switch you use is more likely to die of old age (weather and other environment cycles over decades) than it is to die of electrical overstress. I used to fly a friend's C-150 that was fitted with some really cheesy plastic rocker switches. One night Dee and I were coming back from Hutchinson where there's an excellent steakhouse on the airport. The venerable ol' 150 suffered it's first known switch failure that night . . . the DOME LIGHT switch. It was used so seldom and at such a LOW current level, there was not enough total activity to keep the contacts clean. I swapped the dome light and landing light switches and everything was still working fine several years later when he sold the airplane. Don't get wrapped around the axle of switch ratings. They seldom have a direct correlation for prediction of performance in owner operated light aircraft. If this were a working airplane that flies 100 hours a MONTH in all kinds of environments as opposed to 50 hours a YEAR in nice VFR days like most lightplanes, then we might take more notice of switch quality and ratings. But given how you're likely to use your airplane, it's not worth the effort to be concerned. Bob . . . ________________________________________________________________________________
From: "David Carter" <dcarter(at)datarecall.net>
Subject: Re: 11937 Besing
Date: Feb 13, 2005
Some, not all, of our 26 A-7s at Des Moines, Iowa in 1980s would have UHF and VHF incapacitated by P static between 20 and 25,000 feet at .8 Mach in cirrus clouds. We couldn't find any specific fixes (had lots of static wicks already on all the planes). Depot at Tinker eventually paid a $million bucks for a contractor to take over a hanger at Sioux City, Iowa (also flying A-7s then) and use high voltage generatorsto induce lots of static electricity in an airframe in the hanger. Determined that the "rolling flow" of electrons from nose to tail was mostly going along the exterior skin panels rather than being carried back on the "stringers". As it flowed aft, it would jump the small air gap between panels and make noise. When a plane was known to be a bad actor, we'd add extra grounding straps to connect adjacent skin panels so the static elec wouldn't jump the slight air gap between panels and make noise. Worst thing, though, was the UHF/VHF antenna in top of vertical stab (swept) - static flowing by those panels near the antennae were the most predictable sources of P static. We put extra grounding straps in that area on all planes. Problem went away - never had another writeup after going through the fleet one time. David ----- Original Message ----- From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net> Subject: AeroElectric-List: Re: 11937 Besing > > >Below is the result of your inquiry. It was submitted by > >Paul Besing (paul(at)kitlog.com) on Sunday, February 13, 2005 at 07:21:13 > > > >Sunday, February 13, 2005 > > > >Paul Besing > > > >, > >Email: paul(at)kitlog.com > >Comments/Questions: Bob, what are your thoughts on static wicks? There > >has been some debate on an RV-10 list about them. Knowing your thoughts > >on how much more reliable radios are nowadaws, I'm surprised to hear so > >many people that want to now put them on airplanes. > > > Static wicks have nothing to do with radio quality or reliability. [ but everything to do with static electricity jumping air gaps in the airframe The radio is fine - just picks up part of the multi-spectrum static being produced. DCC] ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> shielded
Subject: Re: How do you carry the braid from a
shielded shielded > > > >Don't quite get the picture. Is this equivalent; bare the shield around the > >circumference, letting it retain it's structure and form, then soldering a > >bare wire around that shield's circumference and taking that wire to the > >ground lug? >Wayne > >Wayne, > >That's a negative. Bob's published way is also....ahem....problematic. The >right way of running a shield through a D-Sub is with a shield--not a >pigtail. The problem can be summarized as follows (and what I say goes for >higher frequencies, not DC): > >1) The shield does what it does because of its geometry. Changing its >geometry changes its response to charges in motion. There is a very big word >to describe this but if I told you.....well....you know! > > 2) Changing the impedance by pigtailing the carefully-constructed coaxial >shield wrecks the impedance and adds a spurious antenna at frequencies >described by the particulars of the pigtail. > >3) Taking care to make the coax think it's still a coax takes special care. > >4) Little of this was common practice before 1980, due somewhat to the >introduction of higher frequencies but moreover DIGITAL stuff since then. >The EMC approvals that became required simply changed common practices. > > From Kimmel Gerke (EMC) Associates---"....all penetrations, such as shields >or cables, be bonded or decoupled at the point of penetration...NO PIGTAILS >or long leads. This is a leading cause of FCC/VDE failures, with poorly >terminated wiring acting as undesired antennas." I've taken a Kimmel-Gerke course and yes, shielding issues are a big deal . . . at HF frequencies and up . . . especially for enclosures. Shielding in airframes is intended to deal with rise-times in the microsecond world, all the faster stuff is filtered off inside the appliances at the connectors. Shielding is used in airplanes for the relatively slow signals allowed by DO-160 and MIL-STD-704 for noisy devices and never for frequencies wherein a pigtail length becomes an issue. >"Cables and Connectors....metal connectors with a full circumferential >termination of cable shield to connector for any cable shield that must work >above 1 MHz...NO PIGTAILS." > >(Emphasis mine) > >The connection of conductors is barely taught in electronics classes, but >consider--- > > What's the difference between a 10A connector and a 100A, 1000A, or a >million-Amp connector? > What's the difference between a DC connector and a 10 MHz connector? > What's the difference between a microvolt connector and a Megavolt >connector? > What's the difference between a gold connector and an aluminum >connector? > > Well...so is there a difference between a coaxial connector and a >pigtail? > >Does it matter? Maybe not. Do you have an aircraft that barely has any >electronics and rarely strays far from the home field or rack full of stuff? >Would like the best quality signals you can get? Do you want radio signals >in that long dark patch between Bandahatchie and Huatabampo? Do you want to >ask the Aeroelectric list how to quiet all the hums and buzzes in your >intercom? >As for the right way to terminate shielded wire---there are a myriad of >ways. Check AMP "Braid-Pic" terminations. Or just browse thru Digikey >section A. Or conceptually--imagine a fat ring-tongue connector. The shield >goes into the sleeve and is soldered there. The center conductor is not >teased out. This is not perfect but is way better than a pigtail. > >And there is still a lot to be said for a good twisted pair below a few GHz. Yeah but . . . we're wrestling with victims and antagonists here that are 100-1000 times more likely to be hosed by magnetically or ground loop coupled noises than electro-static. I cannot recall a single noise problem in 30 years where adding (or fixing existing shields) was the issue. I've worked radiated issues that shielding would not fix but lumped-constant filters did. The problem I worked over the Xmas holidays on a Beechjet and now working on a Hawker are magnetically coupled . . . one case involves a a wire that was shielded trying to fix the problem! I'm also working a problem on T-6 that is 95% sure to be ground loop coupled. Yes, shield pigtails CAN be important but in very rare circumstances on airplane interconnection harnesses . . . this is because of the suggestions offered by DO-160 testing that make most of our accessories relatively robust IRRESPECTIVE of effects of external wiring. One of the first questions I get from a technically founded reviewer is "did you consider ways to eliminate the need for shielded wires you're calling out in the diagrams?" We are encouraged to minimize the use of shielded wire for weight and labor considerations. Once I've jumped the DO-160 hurdles, there are VERY FEW cases where shielding is necessary or even noticeably beneficial. Case in point . . . the wires running from strobe power supplies are twisted trios with all outbound electrons matched by inbound electrons. I'll bet that the shielding of that wire offers no demonstrable benefits other than insurance against an invasion of pink elephants . . . but yes, there is a sharp rise time trigger pulse of 300 volts or more that runs out that wire . . . having a shield is not a bad idea but it's certainly not going to stand or fall on the length of a pigtail that carries it through a connector. I did work a relay life issue where shielding was part of root cause of the problem. Seems that the transmission line effects of 30' of shielded wire with a high quality, dynamic dead short at the far end (filter capacitor) was exacerbating the tendency of perfectly good relay contact to stick. Simply opening the shield grounds cause relay life to jump 10x or so. I'll send you the report on this if you'd like to see it . . . this was a situation that cost us a ton of dollars and was based on a design issue that's never considered when it comes to deciding whether or not a wire should be shielded. I'm not trying to say that shield pigtails never make a difference but in the aircraft world, they're not an issue. Remember that the guys at K-G work the whole spectrum of RFI/EMI issues where the vast majority of their clients are consumer products customers. DO-160 conducted emissions and susceptibility requirements reduce wire shielding to a very low order of probability for noise issues and we NEVER depend on wire shielding for performance at RF. Bob . . . ________________________________________________________________________________
Date: Feb 13, 2005
From: sarg314 <sarg314(at)comcast.net>
Subject: paranormal resistance
Here's one for electric Bob: This is not really relevant to building a plane, but I observed something when making my battery cable that I cannot explain. I used Bob's method for soldering lugs onto a #02 cable using a propane torch. The soldering went as expected. Maybe 20 seconds after I was finished, with the cable still pretty hot, I used my multi-meter to measure the resistance of the cable. I have no sensible reason for doing this. The odd thing is that the resistance showed as 3 ohms. As the minutes went by the indicated resistance dropped steadily. The meter is a Fluke model 11 and seems to have an accuracy of about 0.1 ohm at the low end of the scale. After the cable was just warm to the touch - probably 80 or 90 deg. F - it still showed 1 ohm, which is 1000 times too much. The resistance continued to drop over the next 5 or 10 minutes until it got down to 0.1 ohm which, I think is as good as 0 with this meter. That's what it usually shows when you short its leads together. Elevated temperature will increase the resistance of a wire, but the resistance was significantly different from 0 when the cable appeared to be nearly at room temperature. Further, I made 2 cables and they both showed the same effect. Could it be some thermocouple effect that is confusing the resistance measuring circuit in the meter? I did noticed that it demonstrated polarity, which points to something like that. That is, if it was indicating 0.8 ohms and I reversed the leads, it would then indicate -0.8 ohms. Negative resistance indicates the meter was pretty confused. Any ideas what was going on here? -- Tom Sargent, RV-6A, engine. ________________________________________________________________________________
Date: Feb 13, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: 11937 Besing
> > >Some, not all, of our 26 A-7s at Des Moines, Iowa in 1980s would have UHF >and VHF incapacitated by P static between 20 and 25,000 feet at .8 Mach in >cirrus clouds. We couldn't find any specific fixes (had lots of static >wicks already on all the planes). Depot at Tinker eventually paid a >$million bucks for a contractor to take over a hanger at Sioux City, Iowa >(also flying A-7s then) and use high voltage generatorsto induce lots of >static electricity in an airframe in the hanger. > >Determined that the "rolling flow" of electrons from nose to tail was mostly >going along the exterior skin panels rather than being carried back on the >"stringers". As it flowed aft, it would jump the small air gap between >panels and make noise. When a plane was known to be a bad actor, we'd add >extra grounding straps to connect adjacent skin panels so the static elec >wouldn't jump the slight air gap between panels and make noise. Worst >thing, though, was the UHF/VHF antenna in top of vertical stab (swept) - >static flowing by those panels near the antennae were the most predictable >sources of P static. We put extra grounding straps in that area on all >planes. Problem went away - never had another writeup after going through >the fleet one time. > >David Excellent anecdote sir. I appreciate it. This perfectly underscores the nefarious nature of p-static. Bob . . . ________________________________________________________________________________
From: TimRhod(at)aol.com
Date: Feb 14, 2005
Subject: Fuse links
Bob: I am using duel light speed electronic ignitions. One I am running off of a battery fuse block with a 5 amp fuse. The second I want to run off a second battery using a fuse llnk as described in your book. The wire run is a 20AWG which I understand would normally be linked with a 24AWG. This is rated for only 3 amps though. I need a 5 amp protection. Can I fuselink a 20AWG with a 22AWG? I dont really want to change the wire run to 18AWG which you recomend in your book to fuse link with 22AWG If not what about an in line fuse of 5Amp? Thanks Tim ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Fuse links
> >Bob: I am using duel light speed electronic ignitions. One I am running >off of a battery fuse block with a 5 amp fuse. The second I want to run >off a >second battery using a fuse llnk as described in your book. The wire run is >a 20AWG which I understand would normally be linked with a 24AWG. This is >rated for only 3 amps though. Recall the recent discussions we've had about current ratings on wire. The 24AWG fusible link is a VERY robust, but weak link in a wire that's rated for approximately twice the current rating for the same voltage drop and temperature rise. The 24AWG fusible link upstream of a 20AWG power conductor would would be fine. The current rating of 24AWG wire in a wire bundle has no practical bearing on the performance of 24AWG wire in a fusible link. It will be VERY robust . . . not unlike the ANL current limiters that will CARRY 200% of rated current indefinitely. >I need a 5 amp protection. Can I fuselink a >20AWG with a 22AWG? I dont really want to change the wire run to 18AWG >which >you recomend in your book to fuse link with 22AWG If not what about an in >line fuse of 5Amp? Thanks Tim An inline fuse would be fine too but have lower reliability numbers due to increased connections. I'd go with 20AWG feeder and 24AWG fusible link . . . or you could build a Battery Bus for the second battery using one of the fuseblocks. The ignition system might run from one of the fuse-block taps while offering opportunities for other duties to be assigned to that battery. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: paranormal resistance
> >Here's one for electric Bob: This is not really relevant to building a >plane, but I observed something when making my battery cable that I >cannot explain. I used Bob's method for soldering lugs onto a #02 cable >using a propane torch. The soldering went as expected. Maybe 20 >seconds after I was finished, with the cable still pretty hot, I used my >multi-meter to measure the resistance of the cable. I have no sensible >reason for doing this. The odd thing is that the resistance showed as 3 >ohms. As the minutes went by the indicated resistance dropped >steadily. The meter is a Fluke model 11 and seems to have an accuracy >of about 0.1 ohm at the low end of the scale. After the cable was just >warm to the touch - probably 80 or 90 deg. F - it still showed 1 ohm, >which is 1000 times too much. The resistance continued to drop over the >next 5 or 10 minutes until it got down to 0.1 ohm which, I think is as >good as 0 with this meter. That's what it usually shows when you short >its leads together. > >Elevated temperature will increase the resistance of a wire, but the >resistance was significantly different from 0 when the cable appeared to >be nearly at room temperature. Further, I made 2 cables and they both >showed the same effect. > >Could it be some thermocouple effect that is confusing the resistance >measuring circuit in the meter? Bingo! > I did noticed that it demonstrated >polarity, which points to something like that. That is, if it was >indicating 0.8 ohms and I reversed the leads, it would then indicate >-0.8 ohms. Negative resistance indicates the meter was pretty >confused. Any ideas what was going on here? Your understanding an retention of simple ideas (in this case the Seebeck effect) has served you well and you have properly deduced root cause for the effects you observed. EVERY connection we make between non-identical conductors will exhibit this phenomenon and except for an observation at elevated temperatures they go largely unnoticed. Modern ohmmeters run very low bias currents and therefore must be sensitive to small voltage changes. My ol' Simpson 260 in the x1 ohms scale might barely display the effect you observed . . . your digital instrument turns out to be quite sensitive to the point of making ohmmeter readings meaningless. I was working in an airplane last week where a crew was working on tail de-ice system that draws a lot of power. I was doing some continuity tests with an ohmmeter on another system and while checking some ground circuits, I could SEE the ohmmeter responding to switching cycles of the de-ice system . . . a real world example of the effects of ground loops. Thanks for sharing this with us. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Wing wiring grounds
> >John and Jay > >The best way to insure a good structural ground is by use of abrasive >bonding brushes to remove the primer and any anodize coating. I obtained >mine from The Yard in Wichita. A 4 piece set, P/N 14706, is $3.95 in the >current catalog. They have a 1/4 inch shaft and 3/32, 1/8, 5/32, and 3/16 >pilots. They have a much more expensive set that is more suited to avionics >shop or production line use. Try 1-800-888-8991 or www.yardstore.com. >Finish with an appropriate ring terminal, bolt, and locknut. Excellent point that illustrates common practice in most vehicular ground systems. When I went to work at Boeing in 1961, the first suit of expendables from the toolcrib to my toolbox was a couple of sizes of bonding brushes. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> starter
Subject: Re: Toggle switch - both master/battery and
starter starter > >With the goal of reducing my switch count, I'm wondering if it's possible >to double up the Master/Battery toggle and Starter switch but not sure >it's possible toggle-switch-wise. At first I thought if I could find a >DPDT switch that is Off-On-(On), I could do it. I've found a red toggle >switchguard that returns a toggle that is in the top position back to >center (which would drop starter back to master on) and leave a toggle >that is in the bottom position alone (master off stays master off). > >Useability sounds good, switch guard up, switch to master on, momentary >full up for starter, returns to master on. With a DPDT switch I could >have one pole control starter, but I'm worried about the master/battery >pole. If it goes from middle position (on) to up position (momentary on >for starter), will there be a brief interruption and if so will that cause >a problem? Don't recommend combining battery master and starter functions but the 'Connection chapter offers a variety of ways to utilize progressive transfer, two pole switches to combine functions. E.G. 2-10 on-on-on works nicely for battery master combined with alternator like the infamous split rocker. 2-50 on-on-(on) or 2-5 on-off-(on) can be used as combination magneto and starter functions. 2-10 is suggested for an OFF-TAXI-LND+TAXI function 2-10 could do an OFF-STROBE-STROBE+NAV function. 2-50 works well for OFF-BOOST-BOOST+PRIME 2-10 has been suggested in wig-wag systems for OFF-ON-WIGWAG function Just keep in mind that combining functions into one control forms a single point of failure for both functions but the risk of problems is very low. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: mag switches
> >hi all > >is see in my aeroelectric book on z-11 generic system that 2-5 switches are >used for mag control, in the section under switches pg 11-18 however 2-3 >switches are described for use on the mag controls, which is correct or are >both correct either works. 2-5's allow combining mag switch operation with starter function. 2-3's work fine too but you need a starter pushbutton. >if using the 2-5 switches i see there is no push button for a start, is this >because of the spring loaded 2-5 switches, so what happens at each switch >when starting the engine Right mag OFF, left mag ON and lift switch to START >right mag, position 1 off, position 2 ??. spring position 3 ??? >left mag, position 1 off, position 2 on, spring position 3 start then back >to position 2 on > >guess what i need is what does off-start/on refer to on the 3 switch >position The right mag must be OFF for the starter to work. This is because most right mags do not have impulse couplers and should be disabled during cranking. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: COM static on 123.05
> > >No COM noise until about 125 hours. >Then it was very annoying at certain frequencies. > >I inspected all of the connections shields and grounds. >I tried filters on some power leads - no help with radiated noise. > >I noticed that there was some play in the distributor caps. >I shimmed the clamps - and the noise went away. > >Problem solved. Joe, thanks for sharing this with us! Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: Toggle switch - both master/battery and starter
> Just keep in mind that combining functions into one > control forms a single point of failure for both functions > but the risk of problems is very low. > My first panel design was full of combined switches - it was very cool. Then I priced those 2-10 switches and decided that having one switch per function was more cool! :-) -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
From: N1deltawhiskey(at)aol.com
Date: Feb 14, 2005
Subject: Re: How do you carry the braid from a shielded
Comments below In a message dated 13-Feb-05 13:14:01 Pacific Standard Time, emjones(at)charter.net writes: >Your comments for coax makes sense when it comes to low energy RF signals. >And coax connectors are designed to do just as you suggest. >Not as quiet as concentric pass-throughs, but a lot better than unshielded. >On the other hand, I have trouble imagining a pass-through using D-sub >connectors that would be concentric. What you seem to suggest is that all shielded >wires be connected using some other kind of connector. What do you have in >mind that would allow us to do what you suggest? >Regards, Doug Windhorn Hi Doug, The issue of what power levels and what frequencies require proper connections is fraught with peril. You might think that audio frequencies are easy, but a square wave is made up of ALL frequencies. (Fourier Series: Signals can be composed by a superposition of an infinite number of sine and cosine functions. The coefficients of the superposition depend on the signal being represented and are equivalent to knowing the function itself.....I bet you already knew that!) Ya, I did, a long time ago; a little reminding brings back the memories. Of course, that is the reason that switching DC currents may produce a pop in the audio system. And probably the reason that a lot of digital devices create RF havoc with some installations. All D-sub connectors have matching covers to which the shield may be grounded. I have some that don't. The benefit of this discussion is that I will be looking into getting some that do. One concern that I have though; perhaps you can answer: If a shielded wire is grounded to the D-sub, I assume the ground is carried through by the terminal frames to a similar ground shield on the other side. Now if the terminal frames are mounted to aluminum mounting panels as are mine, either those panels must be electrically isolated from the airframe somehow, or we may get into dealing with a ground loop condition. Plausible? I would not be going very far out on the limb to say that all coaxial and common shielded cables have matching connectors. Agreed. There are of course ungrounded shields--but you can get pretty much anything--so there's no accounting for taste. My description of how coaxial cable and shielded cable should be terminated would be helped by illustrations--none of which I have. But I assure you that this has been the standard technique since the 1980's. Don't doubt the efficacy of your recommendations. Only question whether they are needed in all cases. I expect many builders to say, "Well...it's good enough." This is my second favorite invitation to disaster right after, "Watch this...Hold my beer." If simple methods work, why do something more difficult/costly? If whatever noise gets into the system is not objectionable, so what. However, if it does get into the system, your comments should certainly give people a places to start looking. Thanks for pointing this issue out. Regards, Doug ________________________________________________________________________________
Date: Feb 14, 2005
Subject: LED Bias Resistors
From: "John Schroeder" <jschroeder(at)perigee.net>
Bob - In the diagram published on your website that shows the circuitry for converting the incandescent low voltage light to an LED, you show power coming off a fuse directly to the LED then thru a 220 ohm resistor then to terminal 5 of the LR3 voltage regulator. There is also a 220 ohm resistor bypass around the LED. Several Questions: 1. Shouldn't the first resistor described above be before the LED not after? 2. With an LED that has a 1.9v forward, 20 milliamps of current and a buss voltage of 13.8v, I get 595 ohms for the resistor. Radio Shack has a 560 ohm and a 680. Is the 560 ohm OK? 3. Would the bypass resistor also be 560 or some other value? I looked in the archives and read an explanation of the need for a bypass resistor, but could not find the explanation for where to put the bias resistor. Most LED diagrams have it on the + battery side, thence to the LED. Many thanks for the help. John Schroeder -- ________________________________________________________________________________
Date: Feb 14, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> starter
Subject: Re: Toggle switch - both master/battery and
starter starter > > > > Just keep in mind that combining functions into one > > control forms a single point of failure for both functions > > but the risk of problems is very low. > > > >My first panel design was full of combined switches - it was >very cool. Then I priced those 2-10 switches and decided >that having one switch per function was more cool! :-) If you have the room, single switches is the way to go EXCEPT very specific functions like DC PWR MASTER switch that schedules battery/alternator operations. There's quite a number of tandem cockpit airplanes under construction wherein panel real estate is more precious. If you're trying to make room for some accessory that helps you fly the airplane better, closing up ranks on switches is at least one way to do that. Bob . . . ________________________________________________________________________________
Date: Feb 14, 2005
From: Richard Tasker <retasker(at)optonline.net>
Subject: Re: LED Bias Resistors
In a series circuit (components connected one after another from +12V to ground) it makes no difference which comes first. The order "+12V, LED, resistor, ground" works the same as "+12V, resistor, LED, ground". Put the parts where it is most convenient Dick Tasker. John Schroeder wrote: > >Bob - > >In the diagram published on your website that shows the circuitry for >converting the incandescent low voltage light to an LED, you show power >coming off a fuse directly to the LED then thru a 220 ohm resistor then to >terminal 5 of the LR3 voltage regulator. There is also a 220 ohm resistor >bypass around the LED. Several Questions: > >1. Shouldn't the first resistor described above be before the LED not >after? > >2. With an LED that has a 1.9v forward, 20 milliamps of current and a >buss voltage of 13.8v, I get 595 ohms for the resistor. Radio Shack has a >560 ohm and a 680. Is the 560 ohm OK? > >3. Would the bypass resistor also be 560 or some other value? > >I looked in the archives and read an explanation of the need for a bypass >resistor, but could not find the explanation for where to put the bias >resistor. Most LED diagrams have it on the + battery side, thence to the >LED. Many thanks for the help. > >John Schroeder > > > ________________________________________________________________________________
Date: Feb 14, 2005
Subject: Re: LED Bias Resistors
From: "Matt Prather" <mprather(at)spro.net>
560ohm overdrives that LED by about 6%. Probably okay, but it may run a little bit warm. Probably not. 560ohm bypass is probably okay too, though the LED may turn on very dimly all of the time, even when there isn't any OV/LV event. Regards, Matt- > > > Bob - > > In the diagram published on your website that shows the circuitry for > converting the incandescent low voltage light to an LED, you show power > coming off a fuse directly to the LED then thru a 220 ohm resistor then > to terminal 5 of the LR3 voltage regulator. There is also a 220 ohm > resistor bypass around the LED. Several Questions: > > 1. Shouldn't the first resistor described above be before the LED not > after? > > 2. With an LED that has a 1.9v forward, 20 milliamps of current and a > buss voltage of 13.8v, I get 595 ohms for the resistor. Radio Shack has > a 560 ohm and a 680. Is the 560 ohm OK? > > 3. Would the bypass resistor also be 560 or some other value? > > I looked in the archives and read an explanation of the need for a > bypass resistor, but could not find the explanation for where to put > the bias resistor. Most LED diagrams have it on the + battery side, > thence to the LED. Many thanks for the help. > > John Schroeder > > -- > > ________________________________________________________________________________
From: "Nigel Harrison" <naharrison(at)manx.net>
Subject: Advice about 24V systems
Date: Feb 14, 2005
Thanks for your input. I'm coming round to the idea that 12V may work out fine. Regards Nigel -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Ken Subject: Re: AeroElectric-List: Advice about 24V systems If I may be so bold - A pound of battery is a pound of battery and it is silly to suggest that there is more energy or safety margin in arranging it into 24 volts rather than 12 volts. Your 12 volt accessories will drain just as much energy as 24 volt accessories for all practical purposes. IMO there is however a real safety margin advantage to sticking with tried and proven 12 volt components such as supplied for use with the stock 912S. THere is more discussion on this in the archives. Ken Nigel Harrison wrote: > > >Dear All, >I am a Europa builder and am planning to install an all-electric set up with >a Grand Rapids EFIS etc. Reading Greg Richter's artlcle on Aircraft wiring, >he is of the opinion that a 24V electrical system will provide much more >safety margin tha a 12V system in the event of generator failure. My >aircraft will have a Rotax 912S. The engine manufacturers have advised me >that "Unfortunately the Rotax electrical system is only 12 V DC.The internal >alternator gives an AC voltage above 24 V at a speed of about 3000 rpm, >which may possibly be suitable, but you would have to design or procure a >rectifier/regulator for 24 V." Can someone advise me whether this alternator >would be suffiiciently powerful to charge 2 x 12V 16Ah batteries in series. >Rotax also mention a rectifier/regulator. Advice on this too would be >useful. > >I have little in the way of electrical knowledge/knowhow, so simple >explanations would be most helpful. > >Thanks > >Nigel Harrison > > ************************************************************* This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus ************************************************************* ************************************************************* This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus ************************************************************* ________________________________________________________________________________
From: "Nigel Harrison" <naharrison(at)manx.net>
Subject: Advice about 24V systems
Date: Feb 14, 2005
Thanks for your help. What I'm fitting is as follows: Grand Rapids Horizon 1 EFIS with EIS, Skymap 111c, Trutrak digitrak autopilot, SL40 comm, Garmin transponder (model yet to be decided upon), and back up ASI, ALT, Compass and electric T/C. In addition there are the usual nav lights & strobes. Regards Nigel -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com]On Behalf Of Robert L. Nuckolls, III Subject: RE: AeroElectric-List: Advice about 24V systems > > > >Thank you Bob for your thoughts and recommendations. I will stay with >aeroelectric. I've ordered the aeroelectric book too. It looks as if I would >be best to go for 12 V with the addition of a second battery as a back up. What is it that you want to "back up"? Most aircraft with a 912 engine are relatively simple. What systems do you plan to carry and what flight operations do you anticipate that demand extra-ordinary power supply reliability? >Am I correct in thinking that if they were connected in parallel this would >allow the generator to charge both? Some sort of switching mechanism could >then allow the back up to be used once the main battery power was used up. You can have as many batteries as you wish and run them in parallel for all normal operations. Active notification of low voltage heralds failure of an alternator whereupon the pilot separates each battery from the others to accomplish their respective tasks. Let's talk about the equipment you plan to carry, how much energy each system requires and how you plan to us the airplane. Bob . . . **************************************************************** This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus **************************************************************** ************************************************************* This email has been scanned by the Manxnet Mail Plus anti-virus system. http://www.manx.net/mailplus ************************************************************* ________________________________________________________________________________
Date: Feb 14, 2005
Subject: Re: LED Bias Resistors
From: "John Schroeder" <jschroeder(at)perigee.net>
Richard - Thanks for the clarification. I'll put the resistor first (before the LED). What effect does the resistor of the same ohms have on the circuit when it taps in on the plus side of the LED and ends on the negative terminal of the LED. This looks a bit like a voltage divider. Thanks, John wrote: > > > In a series circuit (components connected one after another from +12V to > ground) it makes no difference which comes first. The order "+12V, LED, > resistor, ground" works the same as "+12V, resistor, LED, ground". Put > the parts where it is most convenient > > Dick Tasker. > > John Schroeder wrote: > >> >> >> Bob - >> >> In the diagram published on your website that shows the circuitry for >> converting the incandescent low voltage light to an LED, you show power >> coming off a fuse directly to the LED then thru a 220 ohm resistor then >> to >> terminal 5 of the LR3 voltage regulator. There is also a 220 ohm >> resistor >> bypass around the LED. Several Questions: >> >> 1. Shouldn't the first resistor described above be before the LED not >> after? >> >> 2. With an LED that has a 1.9v forward, 20 milliamps of current and a >> buss voltage of 13.8v, I get 595 ohms for the resistor. Radio Shack >> has a >> 560 ohm and a 680. Is the 560 ohm OK? >> >> 3. Would the bypass resistor also be 560 or some other value? >> >> I looked in the archives and read an explanation of the need for a >> bypass >> resistor, but could not find the explanation for where to put the bias >> resistor. Most LED diagrams have it on the + battery side, thence to >> the >> LED. Many thanks for the help. >> >> John Schroeder >> >> >> > > -- ________________________________________________________________________________
Date: Feb 14, 2005
From: "Richard E. Tasker" <retasker(at)optonline.net>
Subject: Re: LED Bias Resistors
Yes, it is a voltage divider of sorts, although since the LED functions with a semi-constant voltage across it, it really works more like a current divider. In other words, the LED really controls what the voltage across the LED and parallel resistor is. The series resistor controls the current through the LED and parallel resistor. The parallel resistor "steals" some current from the LED and causes it to stop lighting at a slightly higher voltage than it would otherwise do. Specifically, (assuming that your LED has approximately 1.9V drop across it when it is lighting) the case with just the series 560 ohm resistor the LED will become too dim to see somewhere around 2 to 3V. If one adds the parallel resistor, the same LED will become just as dim at 4 to 5V. Add a smaller value in parallel and the difference becomes even more. All this mainly serves to make the LED brightness follow more closely an incandescent lamp when both are adjusted with a dimmer circuit. By the way, adding the parallel resistor reduces the current through the LED and in your case puts the maximum current down below 20 mA - so your LED is not "overdriven" as you expected! Dick Tasker John Schroeder wrote: > >Richard - > >Thanks for the clarification. I'll put the resistor first (before the >LED). What effect does the resistor of the same ohms have on the circuit >when it taps in on the plus side of the LED and ends on the negative >terminal of the LED. This looks a bit like a voltage divider. > >Thanks, > >John > > > wrote: > > > >> >> >>In a series circuit (components connected one after another from +12V to >>ground) it makes no difference which comes first. The order "+12V, LED, >>resistor, ground" works the same as "+12V, resistor, LED, ground". Put >>the parts where it is most convenient >> >>Dick Tasker. >> >>John Schroeder wrote: >> >> >> >>> >>> >>>Bob - >>> >>>In the diagram published on your website that shows the circuitry for >>>converting the incandescent low voltage light to an LED, you show power >>>coming off a fuse directly to the LED then thru a 220 ohm resistor then >>>to >>>terminal 5 of the LR3 voltage regulator. There is also a 220 ohm >>>resistor >>>bypass around the LED. Several Questions: >>> >>>1. Shouldn't the first resistor described above be before the LED not >>>after? >>> >>>2. With an LED that has a 1.9v forward, 20 milliamps of current and a >>>buss voltage of 13.8v, I get 595 ohms for the resistor. Radio Shack >>>has a >>>560 ohm and a 680. Is the 560 ohm OK? >>> >>>3. Would the bypass resistor also be 560 or some other value? >>> >>>I looked in the archives and read an explanation of the need for a >>>bypass >>>resistor, but could not find the explanation for where to put the bias >>>resistor. Most LED diagrams have it on the + battery side, thence to >>>the >>>LED. Many thanks for the help. >>> >>>John Schroeder >>> >>> >>> >>> >>> >> >> > > > > ________________________________________________________________________________
Date: Feb 14, 2005
Subject: Re: LED Bias Resistors
From: "Matt Prather" <mprather(at)spro.net>
Hi John, LED's have, by their nature, extremely non-linear relationship between voltage and current - unlike the textbook resistor. So, when you start to pump current through a diode, the voltage across it goes up and up until you get to a voltage where it biases on. Then the voltage rise slows down a bunch for the same change in current. The effect in the circuit is that you have a resistor operating where R = V/I = 1.9V/.02A = 95ohm. Remember, this is not a real resistor, but something that we're just modeling as one for the moment. Back to your question... When you put a 95ohm resistor in parallel with a 560ohm resistor (the one making the voltage divider), the lower resistance gets the most current... Req = 1 / (1/R1 + 1/R2) = 1 / (1 / 95 + 1 / 560) = 81ohm. So adding the 560 ohm resistor made the equivalent resistance drop from 95 ohm to 81 ohm. We'll ignore that the LED is now operating at a different IV point; this is close enough. If we were still dropping 1.9V across the diode and hence also across the parallel resistor, I = V/R = 1.9V/560ohm = 3mA. Not a big deal. Close to 20mA is still going through the diode. To figure the precise size of the bypass resistor, we'd need to know what the output characteristics of the circuit driving it (what's the keepwarm voltage), and more precise data about the IV curve for the LED. You could measure the output characteristics of the module, and the IV curve for the diode. Then we could figure out how much bypass was required to keep the LED dark. In practice, I am going to guess that the keepwarm voltage is low enough that any resistor in the 100ohm to 1kohm range will probably do the trick, - keep from forward biasing the diode enough to produce light. An easy way to check it out is wire it up in the hangar some night using a pot instead of a fixed resistor. Twiddle with the resistance of the pot to get what you want, measure the resistance value you get and then pick a resistor that gets you close. Regards, Matt- > > > Richard - > > Thanks for the clarification. I'll put the resistor first (before the > LED). What effect does the resistor of the same ohms have on the circuit > when it taps in on the plus side of the LED and ends on the negative > terminal of the LED. This looks a bit like a voltage divider. > > Thanks, > > John > > > wrote: > >> >> >> In a series circuit (components connected one after another from +12V >> to ground) it makes no difference which comes first. The order "+12V, >> LED, resistor, ground" works the same as "+12V, resistor, LED, >> ground". Put the parts where it is most convenient >> >> Dick Tasker. >> >> John Schroeder wrote: >> >>> >>> >>> Bob - >>> >>> In the diagram published on your website that shows the circuitry for >>> converting the incandescent low voltage light to an LED, you show >>> power coming off a fuse directly to the LED then thru a 220 ohm >>> resistor then to >>> terminal 5 of the LR3 voltage regulator. There is also a 220 ohm >>> resistor >>> bypass around the LED. Several Questions: >>> >>> 1. Shouldn't the first resistor described above be before the LED >>> not after? >>> >>> 2. With an LED that has a 1.9v forward, 20 milliamps of current and >>> a buss voltage of 13.8v, I get 595 ohms for the resistor. Radio >>> Shack has a >>> 560 ohm and a 680. Is the 560 ohm OK? >>> >>> 3. Would the bypass resistor also be 560 or some other value? >>> >>> I looked in the archives and read an explanation of the need for a >>> bypass >>> resistor, but could not find the explanation for where to put the >>> bias resistor. Most LED diagrams have it on the + battery side, >>> thence to the >>> LED. Many thanks for the help. >>> >>> John Schroeder >>> >>> >>> >> >> > > > -- > > ________________________________________________________________________________
From: "Dennis Johnson" <pinetownd(at)volcano.net>
Subject: Stereo vs. Mono Headphone Jacks
Date: Feb 14, 2005
Greetings, I'm starting the electrical planning for my Lancair Legacy and wonder about the advantages and disadvantages of stereo vs. mono headphone jacks. At this point, I don't see any need for stereo headphones, but if there aren't any significant disadvantages, I wonder if it would be wise to wire for stereo in case my plans change in the future. What happens if I plug mono headphones into a stereo jack and vice versa? Any other thoughts? Thanks, Dennis Johnson Lancair Legacy ________________________________________________________________________________
From: "James E. Clark" <james(at)nextupventures.com>
Subject: Stereo vs. Mono Headphone Jacks
Date: Feb 15, 2005
Go STEREO. In that Legacy on those LONG cross country trips, either you or your passenger will just LOVE to listen to you Ipod or other MP3 player while enroute. You will want to do it in STEREO. I see NO downside to stereo but if you wire it mono and want it later it will be a pain to do. Many stereo headsets have a stereo/mono switch so if you plugged them into a mono system and heard stuff in just one ear, slide the switch and you've got "mono both". James | -----Original Message----- | From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- | aeroelectric-list-server(at)matronics.com] On Behalf Of Dennis Johnson | Sent: Monday, February 14, 2005 9:08 PM | To: aeroelectric-list(at)matronics.com | Subject: AeroElectric-List: Stereo vs. Mono Headphone Jacks | | | | Greetings, | | I'm starting the electrical planning for my Lancair Legacy and wonder | about the advantages and disadvantages of stereo vs. mono headphone | jacks. At this point, I don't see any need for stereo headphones, but if | there aren't any significant disadvantages, I wonder if it would be wise | to wire for stereo in case my plans change in the future. What happens | if I plug mono headphones into a stereo jack and vice versa? Any other | thoughts? | | Thanks, | Dennis Johnson | Lancair Legacy | | | | | ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: LED Bias Resistors
> > >Bob - > >In the diagram published on your website that shows the circuitry for >converting the incandescent low voltage light to an LED, you show power >coming off a fuse directly to the LED then thru a 220 ohm resistor then to >terminal 5 of the LR3 voltage regulator. There is also a 220 ohm resistor >bypass around the LED. Several Questions: > >1. Shouldn't the first resistor described above be before the LED not >after? You can wire it several ways with lots of different resistors. The reason I provided the schematic shown is to take advantage of resistors sold in PAIRS from Radio Shack. The shunt resistor is necessary because of some light-off bias current that flows in the output lamp driver for the LR-3. This design was developed so that the warning light will still illuminate even when all power is removed from the LR-3. The residual bias won't light the incandescent lamp but causes a noticeable output from an LED if not swamped out by the parallel resistor. A pair of 220 ohm resistors wired as suggested provides about 35 mA of drive to an LED when the LR-3 is flashing the lamp. 220 was picked because it's a commonly stocked value at Radio Shack and comes in a blister-pak of 2. Other configurations will obviously work too . . . but may optimize with values not so easily obtained and you may have to buy two pairs if different values meaning that you throw away the extras. Folks are making this into a much larger issue than it needs to be. The schematic shown was well considered, tried on the bench and is recommended as published. Works good and lasts a long time. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com>
Subject: Re: How do you carry the braid from a shielded...
Back to my original question... Am I asking for trouble by running my Whelan-type strobe wires through a mil spec molex connect at the wing root? If so, then what sort of connector might be used? If none, then I get to buy more wire and terminate only at the power supply... Thanks, Jay shielded Case in point . . . the wires running from strobe power supplies are twisted trios with all outbound electrons matched by inbound electrons. I'll bet that the shielding of that wire offers no demonstrable benefits other than insurance against an invasion of pink elephants . . . but yes, there is a sharp rise time trigger pulse of 300 volts or more that runs out that wire . . . having a shield is not a bad idea but it's certainly not going to stand or fall on the length of a pigtail that carries it through a connector. ===== __________________________________ ________________________________________________________________________________
From: "Jim Butcher" <europa(at)triton.net>
Subject: Dual Alternators
Date: Feb 15, 2005
I am fitting a second alternator to a Rotax 914. It is a B&C L60 driven off the crank shaft so will generate about 40A at 5000 RPM. The circuit I'm using is Z-13. Is there a problem in having both alternators "turned on" at the same time, ie DC Power Master Switch ON to operate the L60 and the Aux Alt ON to operate the S704-1 relay? Seems like some have said the Rotax (Ducatti) regulator will not tolerate this. Thanks Jim Butcher Europa A185 N241BW ________________________________________________________________________________
Subject: Stereo vs. Mono Headphone Jacks
Date: Feb 15, 2005
From: "Bordelon, Greg" <gbordelon(at)hess.com>
Dennis, I am in the mist if a panel redo.....and I am going to install a small slide or toggle switch next to the headset jacks to allow me to switch from stereo to mono when needed. If you wire it stereo only, when you plug in a mono headset you'll only hear the audio in one ear. With a switch you could rectify that..... Greg -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Dennis Johnson Subject: AeroElectric-List: Stereo vs. Mono Headphone Jacks --> Greetings, I'm starting the electrical planning for my Lancair Legacy and wonder about the advantages and disadvantages of stereo vs. mono headphone jacks. At this point, I don't see any need for stereo headphones, but if there aren't any significant disadvantages, I wonder if it would be wise to wire for stereo in case my plans change in the future. What happens if I plug mono headphones into a stereo jack and vice versa? Any other thoughts? Thanks, Dennis Johnson Lancair Legacy ________________________________________________________________________________
From: Speedy11(at)aol.com
Date: Feb 15, 2005
Subject: Battery Buss
Listers, Please correct me if I'm wrong. The way I see it, the only reason I need a battery buss is to provide always available power for things such as engine ignition, clock, or small courtesy lights. If I don't have any of those things, then I could do without a battery buss. Stan Sutterfield Tampa www.rv-8a.net ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Battery Buss
> >Listers, >Please correct me if I'm wrong. The way I see it, the only reason I need a >battery buss is to provide always available power for things such as engine >ignition, clock, or small courtesy lights. If I don't have any of those >things, >then I could do without a battery buss. Correct. Technically, the single always hot feed from battery to the e-bus alternate feed switch is a "battery bus" connection but it can be much simpler than a fuseblock with multiple taps. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> shielded...
Subject: Re: How do you carry the braid from a
shielded... shielded... > > >Back to my original question... Am I asking for trouble by running my >Whelan-type strobe wires through a mil spec molex connect at the wing root? If >so, then what sort of connector might be used? If none, then I get to buy more >wire and terminate only at the power supply... carrying shield connections through connectors on separate pins is a time honored technique well founded both in physics and practice throughout the aviation industry and many others. Bob . . . ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Alternator light misteries
Date: Feb 15, 2005
Hi guys, I am wiring up a dual battery, single alternator setup using an internally regulated ND alternator (55 amp) for a dual computer, dual fuel pump Subaru engine. My system will be somewhat simpler than Z-14 (which has dual batteries, dual alternators and a crossfeed function). Basically this: * Battery A feeds engine bus A * Battery B feeds engine bus B * Battery A feeds main power bus (strictly VFR, no electric flaps, trim or anything, so all of this electricity is a luxury item and not strictly needed, hence no attempt to connect to battery B in case number A fails. Tough luck for ATC) * Battery B feeds starter (I could use two starter solenoids and a toggle switch to enable battery B starting as well, but these solenoids are HEAVY). Now, normal starting will be with engine on battery A and starter on B. If I run down battery A, I can switch to battery and engine bus B, and still use the starter. * Alternator feeds both batteries through a 70 amp diode to each battery. No problems so far (unless you think that I've got this design all wrong), until I got to the point of wiring up the alternator light. This one is supposed to go to +12V. But which one? The alternator is feeding both systems, so I guess either battery A or B would do? Can someone elaborate on what the true function of this light really is? What is it telling me? What if the light bulb breaks, will that affect alternator operation? Could I wire in a diode-resistor combo, or does it need to be a light bulb? Do I really need this light, or would a negative amps alarm on my ammeter(s) make more sense? Thanks! Hans ________________________________________________________________________________
Subject: Re: LED Bias Resistors
Date: Feb 15, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
Robert L. Nuckolls, III wrote: > A pair of 220 ohm resistors wired as suggested provides about 35 mA of > drive to an LED when the LR-3 is flashing the lamp. 220 was picked > because it's a commonly stocked value Bob - My problem is that 35 milliamps of current, when the LR-3 provides the signal, will put 1.75 times the amount of current specified by the NKK LED lamps we are using. I came up with 560 because that gives me a tolerable bit of overdrive and I can get the resistors at Radio Shack. That is the basis of my original question. Thanks, John ________________________________________________________________________________
Date: Feb 15, 2005
From: "Bob C. " <flyboy.bob(at)gmail.com>
Subject: Re: How do you carry the braid from a shielded...
Now that's the kind of answer I like . . . wasn't that the original question?! wrote: shielded... > > > > > > > >Back to my original question... Am I asking for trouble by running my > >Whelan-type strobe wires through a mil spec molex connect at the wing root? If > >so, then what sort of connector might be used? If none, then I get to buy more > >wire and terminate only at the power supply... > > carrying shield connections through connectors on separate > pins is a time honored technique well founded both in physics > and practice throughout the aviation industry and many others. > > Bob . . . > > > > ________________________________________________________________________________
Date: Feb 15, 2005
From: "Ken Simmons" <ken(at)truckstop.com>
Subject: Aerospace Logic instruments
I'm thinking/planning on installing a couple of the digital instruments from Aerospace Logic to replace some analog Mitchell instruments. The manuals for the digital instruments state they are internally fused and that an external fuse/breaker is not necessary, just tie them to the battery buss. Is this an OK/wise thing to do? I think I would feel more comfortable with at least a common fuse/breaker protecting the set. Thanks. Ken ________________________________________________________________________________
Date: Feb 15, 2005
From: rv-9a-online <rv-9a-online(at)telus.net>
Subject: Re: Aerospace Logic instruments
Ken, the purpose of the fuses in the aircraft are to protect the wiring, not the instruments. If you follow their advice, and you had a wiring short, you could have a combustion event... and the instrument fuse would never blow. Conversely, external fuses are not there to protect the instrument. Instruments should have their own internal protection, if required. Vern Little RV-9A http://www3.telus.net/aviation/flying/RV-9A/rv-9a.html http://www3.telus.net/aviation/vx.html Ken Simmons wrote: > >I'm thinking/planning on installing a couple of the digital instruments from Aerospace Logic to replace some analog Mitchell instruments. The manuals for the digital instruments state they are internally fused and that an external fuse/breaker is not necessary, just tie them to the battery buss. > >Is this an OK/wise thing to do? I think I would feel more comfortable with at least a common fuse/breaker protecting the set. > >Thanks. >Ken > > > > > > > ________________________________________________________________________________
Date: Feb 15, 2005
Subject: Re: Dual Alternators
From: James H Nelson <rv9jim(at)juno.com>
Jim, Use a seperate regulator for the 40A alternator and leave the Duccati for the Rotax unit. I used the B&C regulator for the 40A unit. Jim Nelson N15JN (sold) ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Heated Pitot Tube Installations - New article
Mike, Thank you for sharing this. Yes, your data tracks nicely with that which I've gathered on a variety of tubes over the years. I dug through the pile of data I have and crafted an article which I've posted at: http://aeroelectric.com/articles/Pitot_Heater/Gauging_Pitot_Heater_Performance.pdf I think this piece will illuminate the decision making processes for installing heated pitot tubes in airplanes. Bob . . . > >Bob, > >A few years ago I tested the 5814 pitot/static tube which is basically >the same as the one you have. You can see the graphed results here >http://www.bmnellis.com/pitotcurrent.htm along with raw data link in the >middle of the page. > >-- >Mike Nellis ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net> question was Size of Fuse
vs. Circuit Breaker - Corrected
Subject: Re: Relays for heated pitot tube circuit
question was Size of Fuse vs. Circuit Breaker - Corrected question was Size of Fuse vs. Circuit Breaker - Corrected > >Bob, > I have a Piper style heated 12 volt pitot. This unit has 2 heating > elements. Each element draws 5 amps and has 16 AWG leads to each element. > I would like to a 2-2 style switch to control the heater. Each heater > element would have it's own fused circuit running 16AWG wire. > Your previous advice has been that relays are not needed to protect the > switch when current draw does not exceed 5 amps. Since this double pole > switch will limit warmed up current to 5 amps per set of contacts in the > switch, will this be sufficient? Will the high "in rush" current > overwhelm the contacts in my Carling Technologies switch? Do I need the > added complexity of relays? Would 14 AWG wire be needed or preferable? Charlie, 16AWG is fine. A two pole switch without relays is fine. You might want to fuse each circuit at 10 or 15A. See: http://aeroelectric.com/articles/Pitot_Heater/Gauging_Pitot_Heater_Performance.pdf Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Aerospace Logic instruments
Good answer Vern! Bob . . . > >Ken, the purpose of the fuses in the aircraft are to protect the wiring, >not the instruments. If you follow their advice, and you had a wiring >short, you could have a combustion event... and the instrument fuse >would never blow. > >Conversely, external fuses are not there to protect the instrument. >Instruments should have their own internal protection, if required. > >Vern Little ________________________________________________________________________________
Date: Feb 15, 2005
From: <chaztuna(at)adelphia.net>
Subject: Re: Relays for heated pitot tube circuit
question was Size of Fuse vs. Circuit Breaker - Corrected ---- "Robert L. Nuckolls wrote: question was Size of Fuse vs. Circuit Breaker - Corrected > > > > > >Bob, > > I have a Piper style heated 12 volt pitot. This unit has 2 heating > > elements. Each element draws 5 amps and has 16 AWG leads to each element. > > I would like to a 2-2 style switch to control the heater. Each heater > > element would have it's own fused circuit running 16AWG wire. > > > > Your previous advice has been that relays are not needed to protect the > > switch when current draw does not exceed 5 amps. Since this double pole > > switch will limit warmed up current to 5 amps per set of contacts in the > > switch, will this be sufficient? Will the high "in rush" current > > overwhelm the contacts in my Carling Technologies switch? Do I need the > > added complexity of relays? Would 14 AWG wire be needed or preferable? > > > Charlie, 16AWG is fine. A two pole switch without relays is fine. > You might want to fuse each circuit at 10 or 15A. See: > > http://aeroelectric.com/articles/Pitot_Heater/Gauging_Pitot_Heater_Performance.pdf > > > Bob . . . Bob, Wow! What can I say? Thank you! I'd of been happy with a simple yes or no answer. I got an entire article on the subject. Charlie Kuss ________________________________________________________________________________
From: "Jim Stone" <jsto1(at)tampabay.rr.com>
Subject: Battery Buss
Date: Feb 15, 2005
Stan, In the Tampa TCA and 30 NM vail, you will need a mode C transponder and com. Sqawking 1200 under the TCA reduces the need for a com, but it's nice to be able to call for help in some instances. Jim Stone Jabiru J450 at KPIE -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Speedy11(at)aol.com Subject: AeroElectric-List: Battery Buss Listers, Please correct me if I'm wrong. The way I see it, the only reason I need a battery buss is to provide always available power for things such as engine ignition, clock, or small courtesy lights. If I don't have any of those things, then I could do without a battery buss. Stan Sutterfield Tampa www.rv-8a.net ________________________________________________________________________________
From: "Kingsley Hurst" <khurst(at)taroom.qld.gov.au>
Subject: Stereo vs. Mono Headphone Jacks
Date: Feb 16, 2005
Bob et al, This topic reminds me of something I have wanted to know for some time now. I'm not too frightened to ask a question on this list as others have suggested but since my knowledge is so limited in this respect, I am a little embarrassed because I am not sure I really know HOW to ask the question. Given that I will have an XCOM 760 com with a built-in VOX intercom, if I purchase an IPOD and/or an AM/FM radio receiver, what do I need to do to be able to selectively listen to each in a headset? I imagine I need something like Bob's Audio Isolation Amplifier but if this is correct, one of many things I don't understand is where the inbuilt VOX intercom fits into all of this. Any help gratefully received thanks but please observe the KISS principle. Kingsley Hurst Europa Classic 281 in Oz ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: LED Bias Resistors
> > >Robert L. Nuckolls, III wrote: > > > A pair of 220 ohm resistors wired as suggested provides about 35 mA of > > drive to an LED when the LR-3 is flashing the lamp. 220 was picked > > because it's a commonly stocked value > >Bob - > >My problem is that 35 milliamps of current, when the LR-3 provides the >signal, will put 1.75 times the amount of current specified by the NKK LED >lamps we are using. I came up with 560 because that gives me a tolerable >bit of overdrive and I can get the resistors at Radio Shack. That is the >basis of my original question. Aha! . . . and entirely different application which probably doesn't need the parallel resistor unless you're planning on having one of these switches double as the low volts warning light. Figure about 2 volts across the lamp and assuming a 14v source, you need (14-2)/.02 = 600 ohms and 560 is plenty close. Further, in my experience the modern LED is VERY tolerant to over-current. We had a bit of a kerfuffle here on the list a few years ago about this. I fabricated an experiment with a wall wart wherein I biased up several LEDs at 5x their rated current (150 versus 30 mA). Plugged them into a little used outlet in the garage and left them. Several years later I took them down when I was pulling wall socket plates off the walls to paint . . . they never got put back. As far as I could see, all LEDs in the experiment were still capable of scorching the retinas off the backs of my eyeballs. Yeah, if you want the LED to run a bizillion hours, there may be value in running at or less than specified current. If you need a bit more light, there's little risk in overdriving the parts to get it. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Alternator light misteries
> >Hi guys, > >I am wiring up a dual battery, single alternator setup using an internally >regulated ND alternator (55 amp) for a dual computer, dual fuel pump Subaru >engine. > >My system will be somewhat simpler than Z-14 (which has dual batteries, dual >alternators and a crossfeed function). Basically this: > >* Battery A feeds engine bus A > >* Battery B feeds engine bus B > >* Battery A feeds main power bus (strictly VFR, no electric flaps, trim or >anything, so all of this electricity is a luxury item and not strictly >needed, hence no attempt to connect to battery B in case number A fails. >Tough luck for ATC) > >* Battery B feeds starter (I could use two starter solenoids and a toggle >switch to enable battery B starting as well, but these solenoids are HEAVY). >Now, normal starting will be with engine on battery A and starter on B. If I >run down battery A, I can switch to battery and engine bus B, and still use >the starter. > >* Alternator feeds both batteries through a 70 amp diode to each battery. > > >No problems so far (unless you think that I've got this design all wrong), >until I got to the point of wiring up the alternator light. This one is >supposed to go to +12V. But which one? The alternator is feeding both >systems, so I guess either battery A or B would do? > >Can someone elaborate on what the true function of this light really is? >What is it telling me? What if the light bulb breaks, will that affect >alternator operation? Could I wire in a diode-resistor combo, or does it >need to be a light bulb? Do I really need this light, or would a negative >amps alarm on my ammeter(s) make more sense? It's an alternator fail light which MAY or MAY not tell all the tales of altenrator failure. I've never bothered to hook one up going instead with active notification of low voltage such as described both in a DIY project or off-the-shelf product. The question I have is why not figure Z-13 with a second battery added. Run engine dependent stuff from independent battery busses and simply run two battery contactors. Close only one contactor for starting. I have a number of builders with this configuration and as far as I know, it has proven satisfactory and doesn't need power diodes. Further, the low voltage warning drives from the main bus as depicted in the diagram. With respect to your last question, waaaayyyyy back when, some alternator designs required this lamp for the alternator to come on line. I don't think this is true any more . . . so if it were my airplane, I'd just eliminate it and ignore the unused terminal on the alternator. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Dual Alternators
> >I am fitting a second alternator to a Rotax 914. It is a B&C L60 driven off >the crank shaft so will generate about 40A at 5000 RPM. The circuit I'm >using is Z-13. Is there a problem in having both alternators "turned on" at >the same time, ie DC Power Master Switch ON to operate the L60 and the Aux >Alt ON to operate the S704-1 relay? Seems like some have said the Rotax >(Ducatti) regulator will not tolerate this. Is this an academic question or are you planning to run both alternators at the same time? Having looked over the schematic of a Ducatti regulator for the Rotax, I don't think this will hurt it. I'm curious as to why you're belting the alternator for reduced power? Why not run an L-40 and set the pulley ratio for full power and save the dollars and weight difference between an L40 and the L60? Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Relays for heated pitot tube
> >Bob, > Wow! What can I say? Thank you! I'd of been happy with a simple yes or > no answer. I got an entire article on the subject. >Charlie Kuss Public schools are rife with individuals who dispense lots of data with neat yes/no or pick-the-right-box answers on a multiple-guess test. Real teachers know that one needs to understand how something works so that when the "student" encounters run the situation again, they are qualified to be a "teacher". It's my fondest wish that folks who get answers from participants here on the list get understanding as well so that they can be a teacher on that subject in the future. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Stereo vs. Mono Headphone Jacks
> > >Bob et al, > >This topic reminds me of something I have wanted to know for some time >now. I'm not too frightened to ask a question on this list as others >have suggested but since my knowledge is so limited in this respect, I >am a little embarrassed because I am not sure I really know HOW to ask >the question. > >Given that I will have an XCOM 760 com with a built-in VOX intercom, if >I purchase an IPOD and/or an AM/FM radio receiver, what do I need to do >to be able to selectively listen to each in a headset? > >I imagine I need something like Bob's Audio Isolation Amplifier but if >this is correct, one of many things I don't understand is where the >inbuilt VOX intercom fits into all of this. > >Any help gratefully received thanks but please observe the KISS >principle. If it were my airplane, I'd add an audio isolation amplifer that handles the stereo source signals to stereo phone and mixes monophonic aircraft sources into both right and left headsets. This eliminates the need for multiple headset jacks and some of the switches proposed on the list of late. See: http://www.aeroelectric.com/Catalog/AEC/9009/9009-700E.pdf Page 1.10 of this document describes how the system you describe is wired. Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Size of Fuse vs. Circuit Breaker
> >Bob, > >The reason I asked . . . I'm building a RV-8 that was partially >completed by another builder . . . he had installed a Gretz Aero >AN5812 heated pitot. The installation instruction say it will draw >from 6.4 to 8.0 amps which would put it in the 100W range. The >predecessor builder had run 16AGW from the pitot to the wing root . . >. > >I was planning on finishing the circuit with 16 and putting a 10A >switch/breaker in to feed this device. Sounds like it "could be" a >little light on start up? Agreed. See: http://aeroelectric.com/articles/Pitot_Heater/Gauging_Pitot_Heater_Performance.pdf If you have breakers, a 25A would be more appropriate and 14AWG wire would be "better". You can switch this with the ordinary toggle switch like the S700-1-3 from B&C. >I learn a lot from this list!? Great! Bob . . . ________________________________________________________________________________
Date: Feb 15, 2005
From: "Robert L. Nuckolls, III" <bob.nuckolls(at)cox.net>
Subject: Com antenna relay??
>Comments/Questions: I am installing a second com radio in my homebuilt >airplane. I want to use an RF coaxial relay to be able to switch between >two radios and one com antenna. I have an audio panel and can use an aux >contact on the com selector switch to change the relay position. Are they >any caveats to doing this? I usually see two antennas on aircraft--one >for each radio. Yup, that's so that you can listen on both radios at the same time. If you use the relay and one antenna, only one radio works at a time in BOTH transmit and receive modes. Bob . . . ________________________________________________________________________________
From: "Richard Talbot" <rwtalbot(at)purephotos.com.au>
Subject: Electrical System Design
Date: Feb 16, 2005
Bob and List, Sorry it has taken me a while to reply to your message. I appreciated the information and I do agree with what you have said here. The B&C product range has an excellent reputation and it is certainly true you get what you pay for. Re the Zeftronics regulator I have researched the R15V00RevA unit that appears to be a fairly good match with the B&C Unit. (http://www.zeftronics.com/documents/pit/R15V00RevA-PIT.pdf) From looking at the datasheet and the schematic it would appear that the unit does not have "Crowbar OV Protection". Given that the unit appears to be designed to handle a 60A alternator, would you expect this to be a disadvantage? From what I can gather there appear to be a few advantages to the Crowbar OV protection: Ability to reset the alternator by re-setting the CB after the fault. Safe discharge of the fault to ground via the breaker. I like both of these ideas in an all electric plane. I have not been able to determine if I would be able to bring the Zeftronics alternator back online if the OV protection was triggered. Ideally, you would like to be able to restart the alternator in flight even if the regulator was faulty? I would assume this would allow you to charge the battery when it became discharged, even if the alternator was not properly regulated. Thanks Richard -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: Re: AeroElectric-List: Electrical System Design > > >Hi Chuck, > >The regulator I mention is the B&C LR16-14 listed on their site for $228. >This regulator is specifically mentioned in Chapter 4 of Bob's book Page >4-7. The implication is that it is the most complete and easiest regulator >to use. As I see it the chapter is aimed at describing why Auto gear is not >a great idea in an aircraft. I do see the point, but the external regulator >alone is worth more than the whole box and dice from Vans. The basic >diagrams also feature the regulator. I designed the earliest versions of the LR series regulators for B&C and most of the original design philosophy persists in present versions. We debated at length whether to offer three separate components (regulator, ov protection, lv warning) or some intermediate combinations. Certainly ANY externally regulated alternator will function just fine with about ANY external regulator. The final decision was driven by a philosophy that encouraged builders to have ALL THREE devices as a part of their power generation system. Further, if the builder's time was worth anything and assuming there's value in reducing risk of installation errors, the decision was made to put all three devices in a single enclosure. So, for about 15 years I've fielded complaints about the cost of this product . . . and offered the idea that it's really three $75.00 products already assembled for you in one box. To be sure, this product line is getting long in the tooth and if B&C expects to maintain the hard won popularity of the product, they should be looking at the next generation devices. The trend in virtually every product using electronics is more capability for less money next week. I understand that Zeftronics already offers similar capability in an integrated alternator controller for about half the price. I asked Bill a few years ago what he was planning to do to obsolete this product and didn't get an answer. The Z-figures feature the LR series regulators but alternatives are offered too. One can assemble generic components like the stone simple Ford regulator, an ov protection system and active notification of low voltage and achieve the same level of performance (if not convenience) for under $100 total. >The alternator in question is the B&C L60. $595 on their website. I would >assume that it is the easiest to use on a B&C regulator. It also makes use >of the technology mentioned in Ch-3. Balanced, better bearings, external >regulation etc. May not be the cheapest way to go. If you purchase a brand new ND alternator from any source and spend the time and effort to achieve a condition equivalent to the B&C L-40 or L-60 alternators, I'll bet the total $time$ expended will exceed the price from B&C. Numbers of folk have offered their own solutions to modifying various alternators based on their own experiences and suggested that these alternatives offer better value. It's a judgement call for every builder to decide how the economics of $time$ fit into their project decisions. It's often been suggested that the average builder (whatever that is) would spend less total $time$ acquiring an airplane if they got a part time job and used the money from that job to pay for an airplane as opposed to building it. It's an acknowledge fact that all education is expensive and the root commodity we all have to invest in getting smarter is $time$. The purchased airplane only makes you better plying the skills of your part time job while building it adds to your knowledge and skills base. So I presume that all of you are driven more by the pleasure of finding things out than you are for the simple task of acquiring and owning an airplane. >Point taken on the batteries and alternators, however on page Z-2 you will >see some of the comments that would lead me to make these statements. > >I suspect the issues come as there are at least two types of people that >lurk here. Some want to advance the state of the art. Some want to build >safe, cheap, reliable airplanes. Both are just as important, but sometimes >there is going to be a difference in opinion. If we were good economists and had real numbers by which one could compare all the options, I suspect that the value judgements would be much easier to make. Opinions would become clearer as to value to any particular task. The whole fuse-block concept was driven by the obvious savings of both $time$ and panel space. The hurdles to jump were based on opinions that there was value in pushing and pulling on breakers while trying to extricate one's bod and machine from a stressful situation. This is where the economics of skills and ability to make troubleshooting decisions with one half of the brain while continuing to be a good pilot with the other drove the architecture. It seems better to design so that you DON'T CARE if a particular component has just crapped than to stack plan-b on top of plan-c but only if plan-k is in effect and oh yeah, keep the airplane pointed in the right direction while doing this mental exercise. With respect to cost-benefit analysis, I've often made the case that (1) if you believe the technical features of the B&C products worthy of desire then you'll spend more $time$ achieving them on your own than by simply purchasing them ready to install. And (2) if you believe there is value in considering the service history on B&C belt driven alternators (less than 1% return for any reason on the whole fleet of alternators produced over the last 15+ years) then perhaps the make/buy/substitute decision is easier yet. We KNOW that alternators are the most highly stressed part in the electrical system and that they figure prominently in many dark-n-stormy-night stories. So, I'll simply suggest that you can't have your cake and eat it too. If the dark-n-stormy-night stories accomplish the author's goal of scaring you into preventative actions, then what actions are appropriate? Best stuff with proven track records or slightly better stuff scarfed off a junk yard car and pushed through somebody's overhaul shop? Well, it DEPENDS on your levels of skill and how to intend to use the airplane. We all have those very personal decisions to make and risks to assume. Yes, it's HARD . . . and this is what makes it largely impossible to do turn-key designs for every contingency. There are turn-key designs out there and thousands of airplanes flying them. When I set out to do the 'Connection, it was not to compete with Tony B or Van's idea of what it takes to make an airplane function. I wanted to open ALL the doors we could find and attempt to explain the physics of what goes on for each of those discoveries. Only then could we propose to go beyond what the turn-key or spam-can systems have offered for decades. I apologize if anyone believes I've mis-represented the 'Connection but it does say right on the cover, that we're going to DESIGN a system . . . not sell you a cookie- cutter approach. If that's what anyone needs, please do take advantage of the EXP-Bus, Van's kits, and/or Tony B's books. I wouldn't propose to push anyone . . . but I think the numbers for performance history combined with arguments for failure tolerant design and operation are pretty clear. Further, they go a long way toward making sure you will not be sharing your own dark-n-stormy-night story with any of us soon. However, if your project is going to fly day-vfr only and you don't mind tinkering with stuff to keep it working, perhaps the approaches offered by the 'Connection are not for you. We've always had a satisfaction guaranteed policy. One can return their book for a refund. I did get one back a few years ago . . . it took quite some time to decide that the 'Connection what not for him. The book was dog eared and coffee stained. But he got his money back anyhow. Bob . . . ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Alternator light misteries
Date: Feb 16, 2005
> > > >Can someone elaborate on what the true function of this light really is? > >What is it telling me? What if the light bulb breaks, will that affect > >alternator operation? Could I wire in a diode-resistor combo, or does it > >need to be a light bulb? Do I really need this light, or would a negative > >amps alarm on my ammeter(s) make more sense? > > It's an alternator fail light which MAY or MAY not tell all the > tales of altenrator failure. I've never bothered to hook one up > going instead with active notification of low voltage such as > described both in a DIY project or off-the-shelf product. > > The question I have is why not figure Z-13 with a second battery > added. Run engine dependent stuff from independent battery busses > and simply run two battery contactors. Close only one contactor > for starting. I have a number of builders with this configuration > and as far as I know, it has proven satisfactory and doesn't need > power diodes. Further, the low voltage warning drives from the > main bus as depicted in the diagram. > > With respect to your last question, waaaayyyyy back when, some > alternator designs required this lamp for the alternator to > come on line. I don't think this is true any more . . . so if > it were my airplane, I'd just eliminate it and ignore the unused > terminal on the alternator. > > > Bob . . . > Thanks Bob, just what the doctor ordered. In fact, what I am doing is exactly like Z-13 with a second battery added. Since the only thing that I *need* electricity for is the engine, I chose not to use a second battery contactor to tie the whole lot together, but rather to keep the second battery separated from the main system, feeding only its own engine bus. If the main electrical system fails, including the alternator, then I don't want to switch on anything but the engine anyway. Benefits: * I just saved 1.5 lbs of weight of the two high current relays (For the main power bus I now use a 30 amp automotive relay which weighs next to nothing, the starter is directly connected to the battery) * Less complexity. The backup battery feeds the backup engine systems plus the starter. Nothing more, and thus hopefully more Murphy-proof than a setup where I could tie the whole lot together. Downsides: * Starting only from one battery One question: you mention that in the setup that you describe, there are no power diodes. How do you keep the backup battery topped up then? Or is the idea to run both battery contactors engaged at the same time? In that case I guess that once you notice that you are draining the batteries, you'd have low voltage on both of them and thus reduced range, when compared to starting with at least one topped off battery? Thanks! Hans ________________________________________________________________________________
From: "Charles Heathco" <cheathco(at)comcast.net>
Subject: Re: Stereo vs. Mono Headphone Jacks
Date: Feb 16, 2005
In Kingslys case and in most others why not just connect the music source directly into the aux input supplied with the Icom? Charlie heathco ________________________________________________________________________________
From: "Werner Schneider" <glastar(at)gmx.net>
Subject: E-Mag/P-Mag electrical info
Date: Feb 16, 2005
For all interested in this kind of magnetos, I did ask them to supply some numbers: -----------------------insert Tom Carlson ---------------------------- Operating input voltage is nominally 5 to 18 volts. The coil charge time is automatically adjusted by the computer to maintain a constant spark power over the range of 8 to 18 volts. Because of the power storage capability the input current can be as little as .2 amp for a useful spark output during startup. Note however that the start mode uses multi-spark firing during start mode witch will use about .5 amp during startup (up to about 300rpm). The P-Mag uses external power (like the E-Mag) for starting. It's power draw from the aircraft buss drops off quickly with rpm so above about 1600 rpm it is drawing no power from the aircraft buss. Without external power (aircraft electrical failure) it will operate self powered well under 1000rpm. Regards, Tom Carlson E-Mag -----------------------insert Tom Carlson ---------------------------- might give some insights Werner ________________________________________________________________________________
From: "Alex Peterson" <alexpeterson(at)earthlink.net>
Subject: Alternators
Date: Feb 16, 2005
A while back on this list there was discussion about whether or not internally regulated alternators would continue to function if the "field" input was turned off. Apparently many alternators will continue to function after the "bootstrap" even if the control power is turned off. I have the 40 amp internally regulated Nippondenso, supplied on my Aerosport engine, but believed to be from Niagara Air Parts. I recently confirmed that when the input circuit is shut off, the alternator indeed shuts down. So, there are different animals out there. Alex Peterson RV6-A 571 hours Maple Grove, MN http://www.home.earthlink.net/~alexpeterson/ <http://www.home.earthlink.net/> ________________________________________________________________________________
Date: Feb 16, 2005
From: Ken <klehman(at)albedo.net>
Subject: Re: Com antenna relay??
If one is going to have two radios then it might be considered an advantage to have two antennas so that one antenna or antenna wiring problem can't fail both radios. Ken Robert L. Nuckolls, III wrote: > > > > >>Comments/Questions: I am installing a second com radio in my homebuilt >>airplane. I want to use an RF coaxial relay to be able to switch between >>two radios and one com antenna. I have an audio panel and can use an aux >>contact on the com selector switch to change the relay position. Are they >>any caveats to doing this? I usually see two antennas on aircraft--one >>for each radio. >> >> > > Yup, that's so that you can listen on both radios at the > same time. If you use the relay and one antenna, only one radio > works at a time in BOTH transmit and receive modes. > > Bob . . . > > > ________________________________________________________________________________
Date: Feb 16, 2005
From: Ken <klehman(at)albedo.net>
Subject: Re: Alternator light misteries
Hans 1. If the alternator quits your low voltage warning will instantly notify you and both batteries will still be fully charged when you make your decision as to what to do/where to go. One could also argue that parallel batteries (no charging diode voltage drop) helps insure fully charged batteries. 2. Make sure you really have a relay capable of supplying 30 amps. Many of those relays are rated 30 or 40 amps but as has been discussed may not be particularly reliable for more than about 20 amps with push on connectors. Therefore I used a contactor for that application. A possible additional benefit of the contactor is that I also routed starter current through it which allows me to kill power to the starter in the event that the starter should stick on. Ken >Thanks Bob, just what the doctor ordered. > >In fact, what I am doing is exactly like Z-13 with a second battery added. >Since the only thing that I *need* electricity for is the engine, I chose >not to use a second battery contactor to tie the whole lot together, but >rather to keep the second battery separated from the main system, feeding >only its own engine bus. If the main electrical system fails, including the >alternator, then I don't want to switch on anything but the engine anyway. > >Benefits: >* I just saved 1.5 lbs of weight of the two high current relays (For the >main power bus I now use a 30 amp automotive relay which weighs next to >nothing, the starter is directly connected to the battery) > >* Less complexity. The backup battery feeds the backup engine systems plus >the starter. Nothing more, and thus hopefully more Murphy-proof than a setup >where I could tie the whole lot together. > > >Downsides: >* Starting only from one battery > > >One question: you mention that in the setup that you describe, there are no >power diodes. How do you keep the backup battery topped up then? Or is the >idea to run both battery contactors engaged at the same time? In that case I >guess that once you notice that you are draining the batteries, you'd have >low voltage on both of them and thus reduced range, when compared to >starting with at least one topped off battery? > >Thanks! > >Hans > > > > ________________________________________________________________________________
From: "Jim Butcher" <europa(at)triton.net>
Subject: Re: Dual Alternators
Date: Feb 16, 2005
Bob, I don't plan to run both but it could happen. I'm running the L60 directly off the crankshaft thru a flex coupling. There isn't room for a belt driven alternator under the cowl. Actually the crank driven alt makes a neat installation and uses space not otherwise used. I think B&C is working on a similar installation. Jim Butcher ________________________________________________________________________________
From: "Gary Casey" <glcasey(at)adelphia.net>
Subject: Ignition switches
Date: Feb 16, 2005
I think I've worked myself into a little bit of a corner. I had my panel built with two separate toggle switches for ignition and a push-button starter switch (no key switch). I had planned to use impulse couplings on both mags. Then at the last minute I decided to use one electronic ignition and then save some weight by eliminating the impulse coupler on the remaining mag. Problem is that cranking should then be done with only one ignition switch on. Any suggestions on what to do? I have a suspicion I need to add the impulse coupling just to avoid the situation where I forget and crank with both ignition switches on. Gary Casey ES/Lycoming ________________________________________________________________________________
Date: Feb 16, 2005
From: Ken <klehman(at)albedo.net>
Subject: Re: Alternators
Yes there are some of these critters out there from other sources as well and I agree this is a desireable property. Your observations are for normal ops with a healthy part of course. The next question that comes to mind is whether this would still shut it down after a regulator failure that is charging at maximum? I'm inclined to think it might not and that independant OV protection is still worth considering. apologies if I'm stating the obvious Ken Alex Peterson wrote: > >A while back on this list there was discussion about whether or not >internally regulated alternators would continue to function if the "field" >input was turned off. Apparently many alternators will continue to function >after the "bootstrap" even if the control power is turned off. I have the >40 amp internally regulated Nippondenso, supplied on my Aerosport engine, >but believed to be from Niagara Air Parts. I recently confirmed that when >the input circuit is shut off, the alternator indeed shuts down. > >So, there are different animals out there. > >Alex Peterson >RV6-A 571 hours >Maple Grove, MN > > ________________________________________________________________________________
From: "Hans Teijgeler" <hans(at)jodel.com>
Subject: Alternator light misteries
Date: Feb 16, 2005
Good points Ken, thanks. Okay.... I guess I am going to think this through a little more. To be honest, I hadn't realised that the contactors are large enough to allow the starter current to run through. This certainly helps. Guess I need to wire in yet another toggle switch. Sigh. Hans > -----Oorspronkelijk bericht----- > Van: owner-aeroelectric-list-server(at)matronics.com [mailto:owner- > aeroelectric-list-server(at)matronics.com] Namens Ken > Verzonden: woensdag 16 februari 2005 14:12 > Aan: aeroelectric-list(at)matronics.com > Onderwerp: Re: AeroElectric-List: Alternator light misteries > > > Hans > 1. If the alternator quits your low voltage warning will instantly > notify you and both batteries will still be fully charged when you make > your decision as to what to do/where to go. One could also argue that > parallel batteries (no charging diode voltage drop) helps insure fully > charged batteries. > 2. Make sure you really have a relay capable of supplying 30 amps. Many > of those relays are rated 30 or 40 amps but as has been discussed may > not be particularly reliable for more than about 20 amps with push on > connectors. Therefore I used a contactor for that application. A > possible additional benefit of the contactor is that I also routed > starter current through it which allows me to kill power to the starter > in the event that the starter should stick on. > Ken > > >Thanks Bob, just what the doctor ordered. > > > >In fact, what I am doing is exactly like Z-13 with a second battery > added. > >Since the only thing that I *need* electricity for is the engine, I chose > >not to use a second battery contactor to tie the whole lot together, but > >rather to keep the second battery separated from the main system, feeding > >only its own engine bus. If the main electrical system fails, including > the > >alternator, then I don't want to switch on anything but the engine > anyway. > > > >Benefits: > >* I just saved 1.5 lbs of weight of the two high current relays (For the > >main power bus I now use a 30 amp automotive relay which weighs next to > >nothing, the starter is directly connected to the battery) > > > >* Less complexity. The backup battery feeds the backup engine systems > plus > >the starter. Nothing more, and thus hopefully more Murphy-proof than a > setup > >where I could tie the whole lot together. > > > > > >Downsides: > >* Starting only from one battery > > > > > >One question: you mention that in the setup that you describe, there are > no > >power diodes. How do you keep the backup battery topped up then? Or is > the > >idea to run both battery contactors engaged at the same time? In that > case I > >guess that once you notice that you are draining the batteries, you'd > have > >low voltage on both of them and thus reduced range, when compared to > >starting with at least one topped off battery? > > > >Thanks! > > > >Hans > > > > > > > > > > > > > ________________________________________________________________________________
Subject: Re: LED Bias Resistors
Date: Feb 16, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
wrote: > Aha! . . . and entirely different application which probably > doesn't need the parallel resistor unless you're planning on having > one of these switches double as the low volts warning light. Figure > about 2 volts across the lamp and assuming a 14v source, you need > (14-2)/.02 = 600 ohms and 560 is plenty close. Bob - These lamps (NKK LB03KW01-5x-Jx) will be in an annunciator panel and are lights only - not lighted switches. We will be using two of them for the Z-14 low voltage warning lights. Based on the inputs so far, I plan to go with a 560 ohm for the bias resistor and will install a 560 as a bypass to start with on the bench. One suggestion is to try the bypass as a pot and work down until one sees the leakage current activating the lamp. Measure the resistance of the pot and install the resistor. Thanks for the help. John -- ________________________________________________________________________________
From: <bakerocb(at)cox.net>
Subject: Wiring Whelan Strobes
Date: Feb 16, 2005
AeroElectric-List message previously posted by: Jay Brinkmeyer > Back to my original question... Am I asking for trouble by running my > Whelan-type strobe wires through a mil spec molex connect at the wing > root? If > so, then what sort of connector might be used? If none, then I get to buy > more > wire and terminate only at the power supply... Thanks, Jay 2/16/2005 Hello Jay, Here is how I solved that problem. 1) I bought some additional connectors and pins of the type that plugs into the Whelen power supply. They are available from Terminal Town and other sources. 2) I ran a cut end of the Whelen provided cables in a continuous snake from each wing tip light all the way to my single power supply in the fuselage leaving a coil of excess cable in the fuselage near each wing root. 3) Then I installed the connectors on the cable cut end and plugged into the power supply. 4) If I ever have to remove my one piece wing I will just unplug the two cable connectors from the power supply, cut the connectors off the cable ends, and pull the cables out of the fuselage.## 5) When I reinstall the wing I just go through the same process as when originally installing the wing by snaking the cable ends dangling from the wing root into the power supply, reinstalling the connectors, and plugging back into the power supply. Considering how seldom one pulls the wings off and how little effort and cost is involved in cutting off and reinstalling the cable end connectors this is the best solution for me. It also eliminates an additional cable connection junction at the wing root. OC ##PS: If one were a really fastidious and pecunious type one could not cut off the connectors, but rather just extract the pins from the connectors for wing removal, and then reinsert the pins upon wing reinstall. ________________________________________________________________________________
Date: Feb 16, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: LED Bias Resistors
> > > wrote: > > > Aha! . . . and entirely different application which probably > > doesn't need the parallel resistor unless you're planning on having > > one of these switches double as the low volts warning light. Figure > > about 2 volts across the lamp and assuming a 14v source, you need > > (14-2)/.02 = 600 ohms and 560 is plenty close. > >Bob - > >These lamps (NKK LB03KW01-5x-Jx) will be in an annunciator panel and are >lights only - not lighted switches. We will be using two of them for the >Z-14 low voltage warning lights. Based on the inputs so far, I plan to go >with a 560 ohm for the bias resistor and will install a 560 as a bypass to >start with on the bench. One suggestion is to try the bypass as a pot and >work down until one sees the leakage current activating the lamp. Measure >the resistance of the pot and install the resistor. That will work. Of course, you'll need to have the annunciator hooked to the output pin of the powered up LR-3 so that the output driver is OFF but the rest of the LR-3 is active. You can put a voltmeter across the LED and adjust the parallel resistor such that the OFF state voltage across the LED is on the order of 1 volt. Bob . . . ________________________________________________________________________________
From: "Glaeser, Dennis A" <dennis.glaeser(at)eds.com>
Subject: Re: Ignition switches
Date: Feb 16, 2005
> I think I've worked myself into a little bit of a corner. I had my panel built with two separate toggle switches for ignition and a push-button starter switch (no key switch). I had planned to use impulse couplings on both mags. Then at the last minute I decided to use one electronic ignition and then save some weight by eliminating the impulse coupler on the remaining mag. Problem is that cranking should then be done with only one ignition switch on. Any suggestions on what to do? I have a suspicion I need to add the impulse coupling just to avoid the situation where I forget and crank with both ignition switches on. Gary Casey ES/Lycoming Gary, If you look at Bob's diagrams (Z11 I think), he shows how to wire the toggle/start switches so that the starter circuit is only energized when the switch for the mag without impulse is in the Off position. Dennis Glaeser Re: Ignition switches -- AeroElectric-List message posted by: Gary Casey glcasey(at)adelphia.net I think I've worked myself into a little bit of a corner. I had my panel built with two separate toggle switches for ignition and a push-button starter switch (no key switch). I had planned to use impulse couplings on both mags. Then at the last minute I decided to use one electronic ignition and then save some weight by eliminating the impulse coupler on the remaining mag. Problem is that cranking should then be done with only one ignition switch on. Any suggestions on what to do? I have a suspicion I need to add the impulse coupling just to avoid the situation where I forget and crank with both ignition switches on. Gary Casey ES/Lycoming Gary, If you look at Bob's diagrams (Z11 I think), he shows how to wire the toggle/start switches so that the starter circuit is only energized when the switch for the mag without impulse is in the Off position. Dennis Glaeser ________________________________________________________________________________
Date: Feb 16, 2005
From: "Robert L. Nuckolls, III" <b.nuckolls(at)cox.net>
Subject: Re: Alternators
> > >A while back on this list there was discussion about whether or not >internally regulated alternators would continue to function if the "field" >input was turned off. Apparently many alternators will continue to function >after the "bootstrap" even if the control power is turned off. I have the >40 amp internally regulated Nippondenso, supplied on my Aerosport engine, >but believed to be from Niagara Air Parts. I recently confirmed that when >the input circuit is shut off, the alternator indeed shuts down. > >So, there are different animals out there. How much current flows into the control lead while the alternator is functioning. Just because the lead has "control" over the normally operating alternator does not answer the question as to what happens if the integrated circuit in the alternator goes sneakers-up. Unless the "control" lead is the POWER SORUCE for the alternator field . . . then there's no guarantee that this lead can be used to disable a failed alternator. If the input current is on the order of 2-3 amps with the alternator not running and falls as the alternator spins up, then the "control" lead is just a signal to the regulator and is vulnerable loss of functionality in the worst case scenario. Bob . . . ________________________________________________________________________________
Date: Feb 16, 2005
Subject: Re: LED Bias Resistors
From: "John Schroeder" <jschroeder(at)perigee.net>
wrote: > That will work. Of course, you'll need to have the annunciator > hooked to the output pin of the powered up LR-3 so that the > output driver is OFF but the rest of the LR-3 is active. Bob - I take it that the "output" pin is Pin 5 (Lamp). That pin gets its power - thru the annunciator LED - from the same fuse as the OV sense pin - pin 3. One wire from the fuse goes directly to the LR-3, pin 3. The other wire from that fuse goes to the annunciator, thru the LED lamp and then to the LR-3 - Pin5. My wiring looks exactly like that in the diagram for the LED mod that started this thread. Thanks, John -- ________________________________________________________________________________
From: <bakerocb(at)cox.net>
Subject: Stereo vs. Mono Headphone Jacks
Date: Feb 16, 2005
AeroElectric-List message previously posted by: "Bordelon, Greg" > Dennis, I am in the mist if a panel redo.....and I am going to install a > small > slide or toggle switch next to the headset jacks to allow me to switch > from stereo to mono when needed. If you wire it stereo only, when you > plug in a mono headset you'll only hear the audio in one ear. With a > switch you could rectify that..... Greg 2/16/2005 Hello Greg and Dennis, There is a more simplistic solution than wiring in a switch. Just go ahead and wire for stereo headsets. Then buy a cheap, simple, stereo to mono, inline plug adapter from Radio Shack or other source. Part number 274-1520 at $2.99 should do it. Keep it in the airplane and if you ever need to plug in a mono headset and want to listen with both ears just use the adapter. OC ________________________________________________________________________________
Date: Feb 16, 2005
From: Dennis Golden <dgolden@golden-consulting.com>
Subject: Re: Dual Alternators
Jim Butcher wrote: > > > Bob, > > I don't plan to run both but it could happen. I'm running the L60 directly > off the crankshaft thru a flex coupling. There isn't room for a belt driven > alternator under the cowl. Actually the crank driven alt makes a neat > installation and uses space not otherwise used. I think B&C is working on a > similar installation. I'd really be interested to see a picture if you have one. -- Dennis Golden Golden Consulting Services, Inc. ________________________________________________________________________________
From: "Pat Hatch" <pat_hatch(at)msn.com>
Subject: Ignition switches
Date: Feb 16, 2005
Gary, Just wire it so that your desired ignition switch must be ON for the starter circuit to be activated. Bob has a schematic somewhere that shows this. Not too difficult though. Pat Hatch RV-6 RV-7 -----Original Message----- From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Gary Casey Subject: AeroElectric-List: Ignition switches I think I've worked myself into a little bit of a corner. I had my panel built with two separate toggle switches for ignition and a push-button starter switch (no key switch). I had planned to use impulse couplings on both mags. Then at the last minute I decided to use one electronic ignition and then save some weight by eliminating the impulse coupler on the remaining mag. Problem is that cranking should then be done with only one ignition switch on. Any suggestions on what to do? I have a suspicion I need to add the impulse coupling just to avoid the situation where I forget and crank with both ignition switches on. Gary Casey ES/Lycoming ________________________________________________________________________________
Date: Feb 16, 2005
From: Jay Brinkmeyer <jaybrinkmeyer(at)yahoo.com>
Subject: wing wiring ground returns
I'm planning to use 14v in my RV-10. Most of the electronics will include actual ground return wires (as apposed to airframe ground). However, if I use returns in wing wiring for landing lights, heated pitot, nav, position, etc. that would require a lot of metal squeezing through a small conduit (3/4"). Is it standard practice to use airframe ground in the wings? If so, are there any docs around that describe the physical "how to" so I get it right the first time? If not, I'm good with that and will attempt to shoe horn everything in the conduit. One other question... Any ballpark estimates on how much of what size wire to order up front? I can do my wing estimate pretty easily, but would like to have enough left over to avoid becoming a repeat shipping offender. Jay ===== __________________________________ http://my.yahoo.com ________________________________________________________________________________
Date: Feb 16, 2005
From: rv-9a-online <rv-9a-online(at)telus.net>
Subject: Re: E-Mag/P-Mag electrical info
Werner, thanks for this. I've been trying to get this data from the manufacturer for a while. I have wired my system to be able to draw power from my Dynon EFIS internal battery. This allows hand-propping or emergency power for the E-Mag. I decided not to wire the backup power for the P-Mag in order to reduce current drain on the backup battery. If I need the backup power, its 'IGN switch to AUX, EFIS ON'. Since the EFIS is usually on, this becomes a single motion in flight if needed. I figured that if I paid for the Dynon battery, I may as well use it! It also powers my engine monitor back-up power input. With my GPSMap 296 internal battery, a primary electrical failure will still allow me to have primary flight instruments, engine instruments and nav (GPS)... and ignition. A handheld Comm completes the picture for redundancy. My design for this in on the Engine page of my schematics, available at: http://www3.telus.net/aviation/vx.html Thanks, Vern Little RV-9A/Aerosport Roller Cam engine/p-mag&e-mag. Werner Schneider wrote: > >For all interested in this kind of magnetos, I did ask them to supply some >numbers: > >-----------------------insert Tom Carlson ---------------------------- >Operating input voltage is nominally 5 to 18 volts. The coil charge time is >automatically adjusted by the computer to maintain a constant spark power >over the range of 8 to 18 volts. > >Because of the power storage capability the input current can be as little >as .2 amp for a useful spark output during startup. Note however that the >start mode uses multi-spark firing during start mode witch will use about .5 >amp during startup (up to about 300rpm). > >The P-Mag uses external power (like the E-Mag) for starting. It's power >draw from the aircraft buss drops off quickly with rpm so above about 1600 >rpm it is drawing no power from the aircraft buss. Without external power >(aircraft electrical failure) it will operate self powered well under >1000rpm. > >Regards, > Tom Carlson > E-Mag >-----------------------insert Tom Carlson ---------------------------- >might give some insights > >Werner > > > > ________________________________________________________________________________
Date: Feb 16, 2005
From: Mickey Coggins <mick-matronics(at)rv8.ch>
Subject: Re: Wiring Whelan Strobes
> ##PS: If one were a really fastidious and pecunious type one could not cut > off the connectors, but rather just extract the pins from the connectors for > wing removal, and then reinsert the pins upon wing reinstall. > Yes, this is theoretically possible, but I've never been able to do it. I have an insertion/extraction tool that I got from Steinair, but I've never been able to remove a pin from a molex connector. If there is a trick, I'd love to know it! Mickey -- Mickey Coggins http://www.rv8.ch/ #82007 Wiring ________________________________________________________________________________
From: "Karen and Robert Brown" <bkbrown(at)ashcreekwireless.com>
Subject: wiring P-Mag ignitions
Date: Feb 16, 2005
I'm installing dual P-Mag ignitions in my RV7A that is wired per the "Connection"...Emagair recommends putting a 5A breaker on each ignition so when you do a run up, you can eliminate the power feed to the ignition system to prove that it's generating it's own power. I have a few 5A switch/breakers I could install to accomplish the above. The one place I've differed from z-11 architecture is that I've installed a L/R/Start ignition switch. My questions are these: 1. Can I simply wire each ignition to it's own 5A fuse on one of my busses and use the ignition switch to eliminate battery power to each ignition during run-up or would it be best to use switch/breakers? I can't think of a good reason I'd want to be able to switch the ignition off in two different places... 2. If I do wire the fused P-Mags to the ignition switch, it seems like these should be wired to the battery bus, correct? Thanks for so much teaching! I learn so much just by my morning reading of this groups messages. Bob Brown RV7A - wiring ________________________________________________________________________________
Subject: Re: Wiring Whelan Strobes
Date: Feb 16, 2005
From: "John Schroeder" <jschroeder(at)perigee.net>
Mickey - The connectors that Whelan uses are AMP Mate 'n Lock connectors. They look like Molex's but are not the same. However, since both types have similar pins and locking mechanisms, removing pins from either depends on the diameter of the pins. You can get .09's or .06's thereabouts diameter pins. Radio Shack has a tool for each pin size. The tool consists of a very thin-walled tube wi/ the inside diameter of that tube being very slightly larger than the pins or sockets - .096 or .066 for sake of argument. The outside diameter is such that you can get the pin inside and the still be able to insert the tube in the socket well of the plug itself. There is a rod that fits into this tube and it has a flattened top so that you can push it with your thumb. Insert the tube into the socket well and push down until you feel a slight click, you then push on the inner rod to force the pin out of the socket to the rear. I did not find a pin remover on Steinair that does this. The two that he shows on the connector page are used to remove machined pins from other connectors eg. AMP CPC's and DSubs. They remove the pins from the back of the connector - not the front. Hope this helps. John > Yes, this is theoretically possible, but I've never been able to do it. > I have an insertion/extraction tool > that I got from Steinair, but I've > never been able to remove a pin from a molex connector. If there is a > > trick, I'd love to know it! > > Mickey -- ________________________________________________________________________________
Date: Feb 16, 2005
From: rv-9a-online <rv-9a-online(at)telus.net>
Subject: Re: wing wiring ground returns
Jay, it's standard practice to ground to the spar. AC 43.13 section 15 gives you the how-to for stud bonding/grounding. I drilled a hole in the spar (!) 1" from the outboard end to accomodate a ground lug, and ran my lighting grounds to this point. Van's OK'd this. Inside the fuselage, I also bonded the spar into the main ground with a 12AWG wire, using a similar technique. Vern Little RV-9A Jay Brinkmeyer wrote: > >I'm planning to use 14v in my RV-10. Most of the electronics will include >actual ground return wires (as apposed to airframe ground). However, if I use >returns in wing wiring for landing lights, heated pitot, nav, position, etc. >that would require a lot of metal squeezing through a small conduit (3/4"). > >Is it standard practice to use airframe ground in the wings? If so, are there >any docs around that describe the physical "how to" so I get it right the first >time? If not, I'm good with that and will attempt to shoe horn everything in >the conduit. > >One other question... Any ballpark estimates on how much of what size wire to >order up front? I can do my wing estimate pretty easily, but would like to have >enough left over to avoid becoming a repeat shipping offender. > >Jay > >===== > > > >__________________________________ >http://my.yahoo.com > > > > ________________________________________________________________________________
From: "Leo J. Corbalis" <leocorbalis(at)sbcglobal.net>
Subject: Re: E-Mag/P-Mag electrical info
Date: Feb 16, 2005
Are you certain that you will not put any voltage spikes into the Dynon electronics. That could be an awfully expensive backup battery ! Leo Corbalis ----- Original Message ----- From: "rv-9a-online" <rv-9a-online(at)telus.net> Subject: Re: AeroElectric-List: E-Mag/P-Mag electrical info > > Werner, thanks for this. I've been trying to get this data from the > manufacturer for a while. > > I have wired my system to be able to draw power from my Dynon EFIS > internal battery. This allows hand-propping or emergency power for the > E-Mag. I decided not to wire the backup power for the P-Mag in order to > reduce current drain on the backup battery. > > If I need the backup power, its 'IGN switch to AUX, EFIS ON'. Since the > EFIS is usually on, this becomes a single motion in flight if needed. > > I figured that if I paid for the Dynon battery, I may as well use it! > It also powers my engine monitor back-up power input. With my GPSMap > 296 internal battery, a primary electrical failure will still allow me > to have primary flight instruments, engine instruments and nav (GPS)... > and ignition. A handheld Comm completes the picture for redundancy. > > My design for this in on the Engine page of my schematics, available at: > > http://www3.telus.net/aviation/vx.html > > Thanks, Vern Little RV-9A/Aerosport Roller Cam engine/p-mag&e-mag. > > > Werner Schneider wrote: > > > > >For all interested in this kind of magnetos, I did ask them to supply some > >numbers: > > > >-----------------------insert Tom Carlson ---------------------------- > >Operating input voltage is nominally 5 to 18 volts. The coil charge time is > >automatically adjusted by the computer to maintain a constant spark power > >over the range of 8 to 18 volts. > > > >Because of the power storage capability the input current can be as little > >as .2 amp for a useful spark output during startup. Note however that the > >start mode uses multi-spark firing during start mode witch will use about .5 > >amp during startup (up to about 300rpm). > > > >The P-Mag uses external power (like the E-Mag) for starting. It's power > >draw from the aircraft buss drops off quickly with rpm so above about 1600 > >rpm it is drawing no power from the aircraft buss. Without external power > >(aircraft electrical failure) it will operate self powered well under > >1000rpm. > > > >Regards, > > Tom Carlson > > E-Mag > >-----------------------insert Tom Carlson ---------------------------- > >might give some insights > > > >Werner > > > > > > > > > > ________________________________________________________________________________
From: Fiveonepw(at)aol.com
Date: Feb 16, 2005
Subject: Re: wing wiring ground returns
In a message dated 2/16/05 10:19:07 AM Central Standard Time, jaybrinkmeyer(at)yahoo.com writes: > Is it standard practice to use airframe ground in the wings? >>>>>>>>>>>> Absolutely, provided they aren't some version/perversion of fiberglass.....! > > If so, are there any docs around that describe the physical "how to" so I > get it right the first > time? If not, I'm good with that and will attempt to shoe horn everything in > the conduit. > >>>>>>>>>>> http://www.aeroelectric.com/Catalog/pub/pub.html#aec9 Just go ahead and getcha one, if you don't already- you will be hard pressed to find anything better to spend the thirty $ on. > One other question... Any ballpark estimates on how much of what size wire > to > order up front? I can do my wing estimate pretty easily, but would like to > have > enough left over to avoid becoming a repeat shipping offender. >>>>>> There is no way to avoid the guilt of repeat shipping- After carefully drawing out my entire schematic and calculating all wire runs of any consequence, I ordered 200' of 22awg wire. Halfway through, I ordered another 100' and STILL wound up ordering another hundred. I now have maybe 20 feet left, and that's for a day/nite VFR -6A! Order lots and order often- you'll be a hero when the dude in the next hangar row over drops by to borrow 6 feet of 18 gauge! Mark ________________________________________________________________________________
From: bnoon12(at)comcast.net
Subject: Re: Wiring Whelan Strobes
Date: Feb 16, 2005
The extractor pin has two sides to it. The copper side without the split is for inserting the pin. The other side (the silver extraction side) has a split that will allow you to "grip" the wire but first you must push firmly past the internal flange lock, then "grip" the wire and it should slide right out. It does take some practice, but if there is no previous damage to the flange, it should come right out. Good luck. -- bnoon12(at)comcast.net Tucson,AZ 85750


February 03, 2005 - February 16, 2005

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