---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 09/25/06: 25 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:54 AM - Re: Re: Avionics bus (Carlos Trigo) 2. 05:35 AM - Re: Re: Avionics bus (Robert L. Nuckolls, III) 3. 05:47 AM - Re: Re: Avionics bus (Kevin Horton) 4. 05:47 AM - Re: Eeeeek! Another fear and question. (Robert L. Nuckolls, III) 5. 07:37 AM - 500W Batt tester (Christopher Stone) 6. 08:16 AM - Re: Avionics ground block (Robert L. Nuckolls, III) 7. 09:10 AM - Re: Avionics ground block (Bob Lee) 8. 09:38 AM - Are all active GPS antennas equilvalent? (Louis Jasperson) 9. 10:14 AM - Re: Eeeeek! Another fear and question. (Hinde, Frank George (Corvallis)) 10. 10:42 AM - Re: Eeeeek! Another fear and question. (wgill10@comcast.net) 11. 11:23 AM - Re: Eeeeek! Another fear and question. (Robert L. Nuckolls, III) 12. 11:27 AM - Re: Eeeeek! Another fear and question. (Robert L. Nuckolls, III) 13. 12:46 PM - Re: Avionics ground block (Robert L. Nuckolls, III) 14. 02:09 PM - Re: Avionics ground block (Jekyll) 15. 02:13 PM - Use or non use ? (DBerelsman@aol.com) 16. 04:18 PM - Re: Avionics ground block (Bob Lee) 17. 05:45 PM - Coax connector question (Neil Clayton) 18. 06:04 PM - Re: Mogas versus 100LL (George Braly) 19. 06:19 PM - Re: Coax connector question (Bill Maxwell) 20. 06:28 PM - Lap solder or D-Sub Pins (Emrath) 21. 06:29 PM - Re: Mogas versus 100LL (A DeMarzo) 22. 07:43 PM - Re: Lap solder or D-Sub Pins (Bob White) 23. 08:31 PM - Re: Avionics ground block (Robert L. Nuckolls, III) 24. 08:33 PM - Re: Use or non use ? (Robert L. Nuckolls, III) 25. 09:45 PM - Re: Avionics ground block (Carl Morgan) ________________________________ Message 1 _____________________________________ Time: 02:54:14 AM PST US From: "Carlos Trigo" Subject: Re: AeroElectric-List: Re: Avionics bus > > The simplest thing to do is run it as-built > and treat it like a TC aircraft . . . carry > hand-held backups. > What does TC aircraft mean? ________________________________ Message 2 _____________________________________ Time: 05:35:29 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Avionics bus --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:48 AM 9/25/2006 +0100, you wrote: > > > > The simplest thing to do is run it as-built > > and treat it like a TC aircraft . . . carry > > hand-held backups. > > >What does TC aircraft mean? Type Certificated (alias SpamCan) Bob. . . ________________________________ Message 3 _____________________________________ Time: 05:47:29 AM PST US From: Kevin Horton Subject: Re: AeroElectric-List: Re: Avionics bus On 25 Sep 2006, at 05:48, Carlos Trigo wrote: > > > > The simplest thing to do is run it as-built > > and treat it like a TC aircraft . . . carry > > hand-held backups. > > > What does TC aircraft mean? Type-certificated, like production Cessnas, Pipers, etc. Kevin Horton Ottawa, Canada ________________________________ Message 4 _____________________________________ Time: 05:47:29 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Eeeeek! Another fear and question. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:48 PM 9/25/2006 +1000, you wrote: >--> AeroElectric-List message posted by: "Kingsley Hurst" > > >Bob, > >You said : > > I was able to design the system so that the relay > > was closed and bounce free before current flowed in the > > contacts. Further, I was able to shut off all current flow > > electronically before the relay contacts were opened. > >You have me with my thinking cap on now ! If the current didn't flow >before the contacts were closed and was shut off before the contacts >opened, what was the purpose in having a relay ? It seems you had >complete control over the current flow without the relay !! Just >wondering ?? I was wondering if someone would pick up on that. You get the prize. When you hook motors to things that control flight surfaces, you need to craft a fail passive architecture. In this case, the electronics were a necessary component of accurate control of pitch trim rate. There's a fat transistor in series with the motor that takes intelligence from other electronics to modulate supply current as needed to maintain the required speed. Obviously, the same transistor can turn the motor OFF as well. I.e., all solid state control. However, several failure modes would cause the fat transistor to stay ON continuously causing a pitch trim runaway. We needed a SECONDARY means for disconnecting pitch trim power and the lowly relay seemed a good candidate due to its very low on-resistance. So, the relay was added but programmed via electronics to close first and open last thereby offering VERY long life contacts. However, monitor circuitry that watches for a "stuck" fat transistor would also open the relay, break power to the motor and illuminate a warning light. Last time I talked to the guys in overhaul, they'd seen only one failure in the total fleet of Lears that might have caused a pitch trim runaway wherein the monitor was called upon to do its job. Interestingly enough, there's a fair number of items returned for repair . . . virtually all needed refurbishment of connection technologies. This device is located high in the vertical fin of the airplane . . . second worst environment in the airplane (hell hole is #1). Products of corrosion and temperature cycles have proven to be the biggest test of our design. The stuff everyone worries about the most (electronics) have proven quite robust and long lived. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:37:21 AM PST US From: Christopher Stone Subject: AeroElectric-List: 500W Batt tester --> AeroElectric-List message posted by: Christopher Stone Bob et al.. FYI West Mountain Radio has a new CBA (computerized battery tester) capable of loading to 500 watts. It doesn't appear on the website yet, but they are advertising it in the model press. I have been using their CBA II (150W) for the past year+ and have found it the best tool available for generating battery discharge curves and managing the health of rechargeable batterys. A 500 watt capable analyzer would allow simulation of battery out and/or alternator out scenarios as well as full load testing of 40 amp alternators. Plus much more! I am in no way affiliated with the manufacture, sale or distribution of this product. I am just a very satisfied end user. Chris Stone RV-8 x2 Newberg, OR ________________________________ Message 6 _____________________________________ Time: 08:16:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:31 PM 9/24/2006 -0700, you wrote: >--> AeroElectric-List message posted by: "Jekyll" > >I'm planning a ground block for panel components using a fast-on tab >ground (purchased from SteinAir) soldered to brass bar stock. I plan >to ground all avionics to this and then run a common ground wire to the >main F/W mounted ground block. My question is thus: do I need to insulate >the ground block from the aluminum frame or will the wires carry the >ground better than the airframe, thus carrying the common ground to the >main block? Check out Figure Z-15 http://aeroelectric.com/articles/Rev11/AppZ_R11J.pdf and the "avionics/panel ground" concept described in. http://aeroelectric.com/articles/Rev11/18Audio_R11.pdf The latest updates to these documents suggest a means for simplifying the ground system. The avionics ground need not be as "hoggy" as the forest-of-fast-on-tabs suggested for the firewall. Yes, the panel ground is insulated from panel structure but it's something of a moot point. Many of your panel mounted electro-whizzies ground internally. The important feature of the ground system that prevents ground loop noise problems is that no single potential victim system grounds in more than one place. I.e. you can have a "string" of grounds that need to be "single point" for the systems that use them. Bob. . . ________________________________ Message 7 _____________________________________ Time: 09:10:20 AM PST US From: "Bob Lee" Subject: RE: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Bob Lee" Hey 'lectric Bob, You wrote: << The important feature of the ground system that prevents ground loop noise problems is that no single potential victim system grounds in more than one place. I.e. you can have a "string" of grounds that need to be "single point" for the systems that use them. >> When the teacher says "The Important feature ..." it is important to make sure I understand. Could you please say that again in a different way so that I might understand? I don't see a string of grounds evering being '"single point" for the systems that use them.' Doesn't a string of grounds connect a device to the previous and the next device in the string? So by definition, the string can't be single point. I've just proved the teacher wrong so I'm very leary of my logic. Where's my bad ASSumption? Regards, confused Bob (Bob Lee) N52BL KR2 Suwanee, GA 91% done only 65% to go! ________________________________ Message 8 _____________________________________ Time: 09:38:06 AM PST US From: "Louis Jasperson" Subject: AeroElectric-List: Are all active GPS antennas equilvalent? --> AeroElectric-List message posted by: "Louis Jasperson" are all the active aviation gps antennas (trimble, king, garmin, lowrance, etc) interchangeable? which specificiation do i need to look at to evaluate the equivalence? _________________________________________________________________ Express yourself - download free Windows Live Messenger themes! http://clk.atdmt.com/MSN/go/msnnkwme0020000001msn/direct/01/?href=http://imagine-msn.com/themes/vibe/default.aspx?locale=en-us&source=hmtagline ________________________________ Message 9 _____________________________________ Time: 10:14:53 AM PST US Subject: RE: AeroElectric-List: Eeeeek! Another fear and question. From: "Hinde, Frank George (Corvallis)" Replace alt feed relay with a switch. The SD8 relay is one of those things that is a second order failure...at least it is assuming you are using the SD8 as a backup to your main alternator....In other words the chances of the relay failing as well as the main alternator failing is extremly small. Of course it means you need to test your SD8 operation regularly.....And you really DON't want to turn off your main alt with the engine running. Frank ________________________________ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John Swartout Sent: Friday, September 22, 2006 2:43 PM Subject: AeroElectric-List: Eeeeek! Another fear and question. Bob, your 9/13/06 post regarding LEDs says in part: Finally, relays are rated amongst the least reliable of components. It behooves us to limit their use where ever practical. Okay. That brings up a question. I'm planning Z13/8 with Z32. Z32 Heavy Duty E-Bus Feed shows the use of a relay to energize the alternate feed path. But Z13/8 also relies on a relay to supply the SD-8's output to the E-Bus. That's two relays that must work for E-Bus operations independent of battery power. Is there a practical way to avoid the built-in weakness of two relays in the E-Bus circuit? John ________________________________ Message 10 ____________________________________ Time: 10:42:29 AM PST US From: wgill10@comcast.net Subject: RE: AeroElectric-List: Eeeeek! Another fear and question. What harm is there in turning off the alternator (open the field) with the engine running? Bill -------------- Original message -------------- From: "Hinde, Frank George (Corvallis)" Replace alt feed relay with a switch. The SD8 relay is one of those things that is a second order failure...at least it is assuming you are using the SD8 as a backup to your main alternator....In other words the chances of the relay failing as well as the main alternator failing is extremly small. Of course it means you need to test your SD8 operation regularly.....And you really DON't want to turn off your main alt with the engine running. Frank From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John Swartout Sent: Friday, September 22, 2006 2:43 PM Subject: AeroElectric-List: Eeeeek! Another fear and question. Bob, your 9/13/06 post regarding LEDs says in part: Finally, relays are rated amongst the least reliable of components. It behooves us to limit their use where ever practical. Okay. That brings up a question. Im planning Z13/8 with Z32. Z32 Heavy Duty E-Bus Feed shows the use of a relay to energize the alternate feed path. But Z13/8 also relies on a relay to supply the SD-8s output to the E-Bus. Thats two relays that must work for E-Bus operations independent of battery power. Is there a practical way to avoid the built-in weakness of two relays in the E-Bus circuit? John matronics.com/Navigator?AeroElectric-List
What harm is there in turning off the alternator (open the field) with the engine running?
 
Bill
 
-------------- Original message --------------
From: "Hinde, Frank George (Corvallis)" <frank.hinde@hp.com>
Replace alt feed relay with a switch.
 
The SD8 relay is one of those things that is a second order failure...at least it is assuming you are using the SD8 as a backup to your main alternator....In other words the chances of the relay failing as well as the main alternator failing is extremly small.
 
Of course it means you need to test your SD8 operation regularly.....And you really DON't want to turn off your main alt with the engine running.
 
Frank

From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of John Swartout
Sent: Friday, September 22, 2006 2:43 PM
To: aeroelectric-list@matronics.com
Subject: AeroElectric-List: Eeeeek! Another fear and question.

 

Bob, your 9/13/06 post regarding LEDs says in part:

 

Finally, relays are rated amongst the least reliable of

   components. It behooves us to limit their use where ever practical.

 

Okay.  That brings up a question.  Im planning Z13/8 with Z32.  Z32 Heavy Duty E-Bus Feed shows the use of a relay to energize the alternate feed path.  But Z13/8 also relies on a relay to supply the SD-8s output to the E-Bus.  Thats two relays that must work for E-Bus operations independent of battery power.  Is there a practical way to avoid the built-in weakness of two relays in the E-Bus circuit?

 

John 



matronics.com/Navigator?AeroElectric-List
________________________________ Message 11 ____________________________________ Time: 11:23:25 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Eeeeek! Another fear and question. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:39 PM 9/25/2006 +0000, you wrote: >What harm is there in turning off the alternator (open the field) with the >engine running? > >Bill IF . . . IF you're opening the field . . . no harm whatsoever. On all TC aircraft, one may turn the alternator ON and OFF at will under any conditions without risk to hardware. Aircraft adaptations of internally regulated alternators pose some risk of damage to the alternator's built in regulator due to load dump if the b-lead is disconnected while the alternator is under load. Now, if the battery is fully charged -AND- all electro-whizzies are OFF, the alternator is not significantly loaded and breaking the b-lead a la Z-24 is low risk. So it's not so much a matter of whether or not the alternator is being spun but a matter of loads on the alternator at b-lead disconnect time. Bob . . . ________________________________ Message 12 ____________________________________ Time: 11:27:03 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Eeeeek! Another fear and question. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:13 PM 9/25/2006 -0500, you wrote: >Replace alt feed relay with a switch. The relay was added to facilitate OV protection . . . > >The SD8 relay is one of those things that is a second order failure...at >least it is assuming you are using the SD8 as a backup to your main >alternator....In other words the chances of the relay failing as well as >the main alternator failing is extremly small. Right. Probability of dual failures on any give tank of fuel is exceedingly small. > >Of course it means you need to test your SD8 operation regularly.....And >you really DON't want to turn off your main alt with the engine running. Yup, preflight testing of all on-board energy sources is a good idea. Most aircraft adaptations of automotive alternators (internally regulated) cannot be turned off once they've been turned on. This makes it difficult to test an SD-8 except to make it the FIRST alternator you turn on at preflight, then OFF, then turn the main alternator ON. If you're main alternator is an externally regulated device, then it may be turned ON and OFF at will under any conditions for any purpose. Bob . . . ________________________________ Message 13 ____________________________________ Time: 12:46:47 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:08 PM 9/25/2006 -0400, you wrote: >--> AeroElectric-List message posted by: "Bob Lee" > >Hey 'lectric Bob, > >You wrote: > ><< >The important feature of the ground system that prevents >ground loop noise problems is that no single potential >victim system grounds in more than one place. I.e. you can >have a "string" of grounds that need to be "single point" >for the systems that use them. > >> > >When the teacher says "The Important feature ..." it is important to make >sure I understand. Could you please say that again in a different way so >that I might understand? I don't see a string of grounds evering being >'"single point" for the systems that use them.' Doesn't a string of grounds >connect a device to the previous and the next device in the string? So by >definition, the string can't be single point. I've just proved the teacher >wrong so I'm very leary of my logic. Where's my bad ASSumption? I've added a third sheet to Z-15 which you can see at: http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z15-3.pdf Look this over and see if the words I used before make more sense . . . Bob . . . ________________________________ Message 14 ____________________________________ Time: 02:09:04 PM PST US Subject: AeroElectric-List: Re: Avionics ground block From: "Jekyll" --> AeroElectric-List message posted by: "Jekyll" Bob: Thanks much. The 3rd page cleared it right up for me. We have both fulfilled our purpose - you have taught and I have learned! Jekyll Read this topic online here: http://forums.matronics.com/viewtopic.php?p=63793#63793 ________________________________ Message 15 ____________________________________ Time: 02:13:57 PM PST US From: DBerelsman@aol.com Subject: AeroElectric-List: Use or non use ? To Bob and the list. I live in Florida and fly an older 182. (Vintage 1976) I am wondering about the best way to preserve these older avionics boxes, relays, contacts, switches and dials. Is it best to: Keep them off whenever they are not used (meaning they could be off for months at a time)... during which time they may be subjected to large ambient temperature changes of 50-120 deg - being inside the cabin of a plane which sometimes must be parked outside in the sun. OR.... Use them as much as possible... thereby exercising the switches and dials and coursing electrons thru every contact... but heating up the old semiconductors still further. Opinions please. ________________________________ Message 16 ____________________________________ Time: 04:18:45 PM PST US From: "Bob Lee" Subject: RE: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Bob Lee" 'lectric Bob wrote: << I've added a third sheet to Z-15 which you can see at: http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z15-3.pdf Look this over and see if the words I used before make more sense . . . >> Just as a point of reference, I'm talking about a conposite aircraft. The diagram makes sense but the words about stringing grounds from your origanal post still don't. What I get from the diagram in the link above is that the stuff on the left side (viewed to read the lettering) is the wing ground. The only stuff that you can string together is the stuff that don't matter like strobes, landing/taxi lights pitot heat and nav lights. Everything else must go the the appropriate (firewall, engine, or pannel) single point ground. Did I get it right this time? Regards, confused Bob ________________________________ Message 17 ____________________________________ Time: 05:45:16 PM PST US From: Neil Clayton Subject: AeroElectric-List: Coax connector question --> AeroElectric-List message posted by: Neil Clayton I'm looking to connect my radio and transponder cables to their respective instruments (ICOM A200 and Garmin 320A). I used RG 58 cable for the radio antennas and RG 400 for the transponder antenna. When I look at available co-ax connectors there seem to be a host of different ones - thread on, push on, screw on, compression, "turn and lock"....I'm totally confused. Can someone educate me about co-ax connectors, so I might at least form a picture of what I should be using? I expect there's a rule set of when to use what. Many thanks Neil -- ________________________________ Message 18 ____________________________________ Time: 06:04:13 PM PST US Subject: RE: AeroElectric-List: Mogas versus 100LL From: "George Braly" --> AeroElectric-List message posted by: "George Braly" >> It's been an interesting thread . . . but never did see any words that were trading off the features of Mogas vs. 100LL . . . I WAS interested because I don't understand how or why they would be compared to each other.<< Bob, 30% of the AVGAS is burned in 70% of the fleet aircraft. 70% of the AVGAS is burned in 30% of the fleet aircraft. The 30% of the fleet aircraft that burns 70% of the AVGAS use engines that REQUIRE a fuel with the octane characteristics of Avgas. If you want to fly higher than about 6000 feet, 100% of the fleet requires fuel with the vapor pressure characteristics of Avgas. The vapor pressure issues are almost universally overlooked. Going back to octane issues, consider that 91 (R+M)/2 premium car gas has a Motor Octane Number ( the "M" in the R +M equation) of about 87-88. UNLEADED refinery builds of otherwise conforming AVGAS have a MON of about 92 to 95. There is a HUGE difference in an 88 MON gasoline and a 92 MON gasoline in terms of how much horsepower one can obtain out of the engine before the onset of detonation. It is important to keep in mind that virtually all major advances in aviation have revolved around improvements in the power to weight ratio of the power plant along with improvements in the brake specific fuel consumption. The use of 88MON gasoline in an engine that requires 92 to 95 MON gasoline will cause the power to weight ratio to have to change by about 30% in the wrong direction. And it gets worse if you think of 100 octane fuels. But just the change from 92-95 MON back to 88 MON gasoline effectively undoes all of the advances in aircraft piston engines going back to about 1935. Into the future, there is normally only going to be one gasoline storage tank at the typical airport used by general aviation. It needs to contain a fuel that will run ALL of the engines. Regards, George PS. Let's leave no engine on the ground! ________________________________ Message 19 ____________________________________ Time: 06:19:45 PM PST US From: "Bill Maxwell" Subject: Re: AeroElectric-List: Coax connector question --> AeroElectric-List message posted by: "Bill Maxwell" Cant speak for the transponder Neil but your your Icom A200 expects to see a BNC co-ax connector heading its way. That's a push on, turn and lock or bayonet fitting. Bill----- Original Message ----- From: "Neil Clayton" Sent: Tuesday, September 26, 2006 10:43 AM Subject: AeroElectric-List: Coax connector question > --> AeroElectric-List message posted by: Neil Clayton > > > I'm looking to connect my radio and transponder cables to their respective > instruments (ICOM A200 and Garmin 320A). > > I used RG 58 cable for the radio antennas and RG 400 for the transponder > antenna. > > When I look at available co-ax connectors there seem to be a host of > different ones - thread on, push on, screw on, compression, "turn and > lock"....I'm totally confused. > > Can someone educate me about co-ax connectors, so I might at least form a > picture of what I should be using? I expect there's a rule set of when to > use what. > > Many thanks > Neil > > > -- > > > ________________________________ Message 20 ____________________________________ Time: 06:28:12 PM PST US From: "Emrath" Subject: AeroElectric-List: Lap solder or D-Sub Pins --> AeroElectric-List message posted by: "Emrath" Bob: I am in the process of wiring some K type thermal couples for my EGT and CHT gage, the UBG-16 from Electronics International. The problem is the supplied thermal couple type K wire is 6' and I really only need 3' or so between the gage and the sensor. The ends of the wires came with pre-crimped 1/4" fast-on connectors. The cable may be shorted as needed per EI and new connectors crimped on. I was thinking cutting the wires to length and then cutting off the mating connector and putting on some solid D-sub pins and cover with heat shrink in order to avoid the "snake swallowed the mouse" look. However, I'm wondering if just a "lap joint" as you show on your shop articles isn't perhaps more robust for the job. I know that thermal couple K wire is different from copper somehow, but can they be soldered like normal copper wires? This will all be under the cowling. Marty RV-6A the long way. Thanks for all you do! ________________________________ Message 21 ____________________________________ Time: 06:29:21 PM PST US From: "A DeMarzo" Subject: RE: AeroElectric-List: Mogas versus 100LL And let me add that after attending the Advanced Pilot Seminar last weekend and actually seeing exactly how MOGAS affects our current engines (watching the real time data of an engine running it), I'm dropping any inclination of using that stuff in any real aviation engine. Regardless of how many tankfuls one may have run through their engine, and how well it has performed, we're just not ready to think that MOGAS is better. In time, when our engine systems become smarter, I'll welcome its use and hope they change the smell of it. Al On 09/25/2006 8:02:37 PM, George Braly (gwbraly@gami.com) wrote: > --> AeroElectric-List message posted by: "George Braly" com> > > > > >> > It's been an interesting thread . . . but never did see > any words that were trading off the features of Mogas > vs. 100LL . . . I WAS interested because I don't > understand > how or why they would be compared to each other.<< > > Bob, > > 30% of the AVGAS is burned in 70% of the fleet aircraft. > 70% of the AVGAS is burned in 30% of the fleet aircraft. > > The 30% of the fleet aircraft that burns 70% of the AVGAS use engines > that REQUIRE a fuel with the octane characteristics of Avgas. > > If you want to fly higher than about 6000 feet, 100% of the fleet > requires fuel with the vapor pressure characteristics of Avgas. > > The vapor pressure issues are almost universally overlooked. > > Going back to octane issues, consider that 91 (R+M)/2 premium car gas > has a Motor Octane Number ( the "M" in the R +M equation) of about > 87-88. > > UNLEADED refinery builds of otherwise conforming AVGAS have a MON of > about 92 to 95. > > There is a HUGE difference in an 88 MON gasoline and a 92 MON gasoline > in ________________________________ Message 22 ____________________________________ Time: 07:43:10 PM PST US From: Bob White Subject: Re: AeroElectric-List: Lap solder or D-Sub Pins --> AeroElectric-List message posted by: Bob White On Mon, 25 Sep 2006 20:27:20 -0500 "Emrath" wrote: > --> AeroElectric-List message posted by: "Emrath" > > Bob: > I am in the process of wiring some K type thermal couples for my EGT and CHT > gage, the UBG-16 from Electronics International. The problem is the supplied > thermal couple type K wire is 6' and I really only need 3' or so between the > gage and the sensor. The ends of the wires came with pre-crimped 1/4" > fast-on connectors. The cable may be shorted as needed per EI and new > connectors crimped on. I was thinking cutting the wires to length and then > cutting off the mating connector and putting on some solid D-sub pins and > cover with heat shrink in order to avoid the "snake swallowed the mouse" > look. However, I'm wondering if just a "lap joint" as you show on your shop > articles isn't perhaps more robust for the job. I know that thermal couple K > wire is different from copper somehow, but can they be soldered like normal > copper wires? This will all be under the cowling. > > Marty RV-6A the long way. > Thanks for all you do! > Hi Marty, I'm not the Bob you were asking, but I can answer your question. In general you can't solder thermocouple wire. Particularly not the J and K types commonly used for A/C temp measurements. I think they will silver solder or they could be spot welded but the simplest thing to do is use the crimp connectors. Either the fast-on or D-sub will work OK. You want to keep the temperature differential across the crimped connections as low as possible to minimize errors. Bob W. > > > > -- http://www.bob-white.com N93BD - Rotary Powered BD-4 (first engine start 1/7/06) Custom Cables for your rotary installation - http://www.roblinphoto.com/shop/ ________________________________ Message 23 ____________________________________ Time: 08:31:30 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:17 PM 9/25/2006 -0400, you wrote: >--> AeroElectric-List message posted by: "Bob Lee" > >'lectric Bob wrote: > ><< I've added a third sheet to Z-15 which you can see at: > >http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z15-3.pdf > > Look this over and see if the words I used before make more > sense . . . > >> > >Just as a point of reference, I'm talking about a conposite aircraft. The >diagram makes sense but the words about stringing grounds from your origanal >post still don't. What I get from the diagram in the link above is that the >stuff on the left side (viewed to read the lettering) is the wing ground. >The only stuff that you can string together is the stuff that don't matter >like strobes, landing/taxi lights >pitot heat and nav lights. Everything else must go the the appropriate >(firewall, engine, or pannel) single point ground. Download the drawing again (I did it in a hurry this morning and was able to spiff it up a bit this evening). If your latest download doesn't come up in color, hit the 'refresh' icon on your browser. All of the stuff in blue is the ground system . . . the ground busses are "strung together" but in 3 separate locations in the a/c. "Local" grounds to airframe may be "scattered" about the airframe on a metal airplane when the item being grounded is not itself a potential victim. In your case for a composite airplane, local grounds are not possible and must, of course, be moved to the cockpit ground bus. Stuff in green have been properly grounded to a single point commensurate with system requirements. For example, CHT and many oil pressure senders ground to the engine . . . so for best accuracy (especially in canard pushers) the attending instrument should also be grounded to the crankcase . . . or at least the firewall ground bus. Stuff in red has been purposely "mis-grounded" to illustrate the potential for inserting errors/noise by tiny but significant voltage differences that may exist between grounds that are connected but not co-located on the airframe. >Did I get it right this time? Closer! Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 24 ____________________________________ Time: 08:33:22 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Use or non use ? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:12 PM 9/25/2006 -0400, you wrote: >To Bob and the list. > >I live in Florida and fly an older 182. (Vintage 1976) > >I am wondering about the best way to preserve these older avionics boxes, >relays, contacts, switches and dials. > >Is it best to: > >Keep them off whenever they are not used (meaning they could be off for >months at a time)... during which time they may be subjected to large >ambient temperature changes of 50-120 deg - being inside the cabin of a >plane which sometimes must be parked outside in the sun. > >OR.... > >Use them as much as possible... thereby exercising the switches and dials >and coursing electrons thru every contact... but heating up the old >semiconductors still further. For the most part, the most environmentally destructive thing you can to do airplanes and their components (including electronics) is to let them sit idle for long periods of time. Obviously, many components have a service life that is used up more rapidly if the airplane is used often. However, unless the airplane is used in a rental fleet the strongest effects are likely to be environmental and generally exacerbated by lack of use. If it were my airplane, I'd operate every switch and rotate every control through a full cycle on every pre-flight. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 25 ____________________________________ Time: 09:45:57 PM PST US From: "Carl Morgan" Subject: RE: AeroElectric-List: Avionics ground block --> AeroElectric-List message posted by: "Carl Morgan" Hi Bob, This leads to a question we have had, we have a 'mid-ship ground forest of tabs' aft of the spar with a dedicated AWG8 between it and the firewall ground 'single point'. Would you advocate insulating the mid ship forest from the main fuselage or just bolting it up to the metal sub structure? Thanks, Carl PS: Small typo in the text on the second page - leas cf least -- ZK-VII - RV 7A QB - finishing? - New Zealand http://www.rvproject.gen.nz/ > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of > Robert L. Nuckolls, III > Sent: Tuesday, 26 September 2006 3:25 p.m. > To: aeroelectric-list@matronics.com > Subject: RE: AeroElectric-List: Avionics ground block > > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, > III" > > At 07:17 PM 9/25/2006 -0400, you wrote: > > >--> AeroElectric-List message posted by: "Bob Lee" > > > >'lectric Bob wrote: > > > ><< I've added a third sheet to Z-15 which you can see at: > > > >http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z15-3.pdf > > > > Look this over and see if the words I used before make more > > sense . . . > > >> > > > >Just as a point of reference, I'm talking about a conposite > aircraft. The > >diagram makes sense but the words about stringing grounds from > your origanal > >post still don't. What I get from the diagram in the link above > is that the > >stuff on the left side (viewed to read the lettering) is the wing ground. > >The only stuff that you can string together is the stuff that > don't matter > >like strobes, landing/taxi lights > >pitot heat and nav lights. Everything else must go the the appropriate > >(firewall, engine, or pannel) single point ground. > > Download the drawing again (I did it in a hurry this morning > and was able to spiff it up a bit this evening). If your > latest download doesn't come up in color, hit the 'refresh' > icon on your browser. > > All of the stuff in blue is the ground system . . . the ground > busses are "strung together" but in 3 separate locations in the a/c. > "Local" grounds to airframe may be "scattered" about the airframe > on a metal airplane when the item being grounded is not itself > a potential victim. In your case for a composite airplane, > local grounds are not possible and must, of course, be moved > to the cockpit ground bus. > > Stuff in green have been properly grounded to a single point > commensurate with system requirements. For example, CHT > and many oil pressure senders ground to the engine . . . so > for best accuracy (especially in canard pushers) the attending > instrument should also be grounded to the crankcase . . . or > at least the firewall ground bus. > > Stuff in red has been purposely "mis-grounded" to illustrate > the potential for inserting errors/noise by tiny but significant > voltage differences that may exist between grounds that are > connected but not co-located on the airframe. > > > >Did I get it right this time? > > Closer! > > Bob . . . > --