---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 04/15/04: 23 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:00 AM - z-14 common failure point (klehman@albedo.net) 2. 06:54 AM - Coaxial Lengths (David E. Nelson) 3. 07:07 AM - Re: z-14 common failure point (Robert L. Nuckolls, III) 4. 07:15 AM - PS: z-14 common failure point (Robert L. Nuckolls, III) 5. 07:15 AM - Re: Copper Clad Aluminum etc. (Robert L. Nuckolls, III) 6. 07:29 AM - Re: A panel full of displays . . . (flyv35b) 7. 07:31 AM - Re: Endurance Bus (F1Rocket@comcast.net) 8. 08:20 AM - Re: Coaxial Lengths (Dave Morris) 9. 09:09 AM - Ignitions/Starting (BFlood@Sauer-Danfoss.com) 10. 09:38 AM - Re: PS: z-14 common failure point (GMC) 11. 11:53 AM - Re: Ignitions/Starting (Matt Prather) 12. 12:40 PM - Dynon heated AOA pitot now available (Bartrim, Todd) 13. 02:13 PM - Re: Ignitions/Starting (Dan Checkoway) 14. 03:06 PM - Re: Re: Architecure Choices (czechsix@juno.com) 15. 03:06 PM - Re: Ignitions/Starting (Sam Hoskins) 16. 03:13 PM - Re: Ignitions/Starting (Sam Hoskins) 17. 03:15 PM - Re: A panel full of displays . . . (czechsix@juno.com) 18. 04:26 PM - Re: Ignitions/Starting (Matt Prather) 19. 05:35 PM - Re: Ignitions/Starting (Pat Hatch) 20. 07:35 PM - Re: Ignitions/Starting (Robert L. Nuckolls, III) 21. 07:57 PM - Re: Ignitions/Starting (Sam Hoskins) 22. 09:21 PM - Re: Ignitions/Starting (Dan Checkoway) 23. 09:43 PM - Re: Ignitions/Starting (Terry Watson) ________________________________ Message 1 _____________________________________ Time: 06:00:02 AM PST US From: klehman@albedo.net Subject: AeroElectric-List: z-14 common failure point --> AeroElectric-List message posted by: klehman@albedo.net The cross-feed relay/contactor in a dual battery and dual alternator Z-14 architecture is a common point of failure. With a small non-cranking second battery, the crossfeed could be fused or protected with fusable links. With two batteries of the same size that both provide cranking current, that becomes more difficult. So today's question is - do crossfeed contactors ever fail in such a manner that one or both feeds short to ground? This question came to mind after observing a Docap 24059 contactor. The studs penetrate the metal case through hard plastic grommets that can't have a terribly high melting point. Now I'm wondering what is inside that could fail and short to the metal case. The Cole Hersee site also lists a "plasticized" 24117 version although I've not seen it stocked locally and it is several times the price. Perhaps I'll just insulate the metal contactor from the metal airframe. thanks Ken ________________________________ Message 2 _____________________________________ Time: 06:54:43 AM PST US From: "David E. Nelson" Subject: AeroElectric-List: Coaxial Lengths --> AeroElectric-List message posted by: "David E. Nelson" Hi Bob, Finished reading through the "Antenna" chapter last night. Back in my pre-teen days, I used to spend some time with a ham operator that operated in the HF band. Although I don't remember the equation, I distinctly remember that he'd measure all his coaxes before cutting and fitting them with connectors. I seem to recall that his reasoning for this was so that the coax was a multiple of the wavelength of the carrier freq. Is this of any relevance to our apps? Thanks, /\/elson Austin, TX RV-7A - Waiting on the wings.... ________________________________ Message 3 _____________________________________ Time: 07:07:39 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: z-14 common failure point --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:57 AM 4/15/2004 -0400, you wrote: >--> AeroElectric-List message posted by: klehman@albedo.net > >The cross-feed relay/contactor in a dual battery and dual alternator >Z-14 architecture is a common point of failure. > >With a small non-cranking second battery, the crossfeed could be fused >or protected with fusable links. With two batteries of the same size >that both provide cranking current, that becomes more difficult. > >So today's question is - do crossfeed contactors ever fail in such a >manner that one or both feeds short to ground? This question came to >mind after observing a Docap 24059 contactor. The studs penetrate the >metal case through hard plastic grommets that can't have a terribly high >melting point. Now I'm wondering what is inside that could fail and >short to the metal case. The Cole Hersee site also lists a "plasticized" >24117 version although I've not seen it stocked locally and it is >several times the price. Perhaps I'll just insulate the metal contactor >from the metal airframe. There's no component I'm aware of that has a failure rate of zero. There are many components with failure rates that are exceedingly small . . . in the same neighborhood as that of prop bolts and wing struts. I'm involved in an investigation of fault-to-ground failure in a solid state contactor that caused a fire . . . fortunately on the ground. One might sit right up in their chair with the wide-eyed stare and declare that this event warrants some rapid response and real "solutions" . . . However, looking at the history of this part (25+ years of service, 4 devices per airplane, fleet size in the upper hundreds, and what must be millions of flight hours with no similar failures) I do not at present perceive a need for such action. The investigation is incomplete but preliminary studies suggest that inattention to assembly procedures is the triggering event . . . not gross failure of any components. Now, do electro-mechanical contactors fail, you betcha. See: http://www.aeroelectric.com/Pictures/6041_Contactor.jpg and http://www.aeroelectric.com/Pictures/6041_Contactor_Failure.jpg This is a $high$ contactor used to control loads of well over 100A with LONG duty cycles. Contact aging increases resistance which in turn increases heat which increases resistance and the end is inevitable. Is the Z-14 crossfeed contactor at risk? It carries a PORTION of cranking current for a few seconds at the beginning of each flight. Its normal operating condition for 99.9% of flight operations is OFF. With B&C hardware for alternators, it's unlikely that the crossfeed contactor will ever be called upon to carry out a primary assigned duty as mitigator of alternator failure over the lifetime of the airplane. Even if it DOES get a call-to-service, it will carry loads at a small fraction of it's rated service and only for perhaps an hour or two until landing. Given the VERY low stress and duty cycle on this contactor, I'll suggest that there are many, many things in your system much more likely to fail than this contactor. Further, given that the continuous duty operating loads are so small, it's extremely unlikely that it will fail in an overheat mode that produces faults to ground due to insulator failure. Now, is the risk of what you've suggested zero? Nope . . . but I wouldn't loose any sleep over this one. Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:15:00 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: PS: z-14 common failure point --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" It just occurred to me that this style contactor has been used on SE certified aircraft for about 60 years as a battery contactor. This offers a tens-of-millions flight-hours experience- base. I've seen a lot of these contactors fail . . . haven't seen any catch fire or fault to ground. This same style contactor is used as battery contactor in OBAM aircraft as well. We're continuing to pile up millions of flight hours history on this part in a CONTINUOUS duty application at substantial current values. If there are valid concerns for the failure mode hypothesized then it's going to happen at the battery long before it happens at the crossfeed contactor. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:15:28 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Copper Clad Aluminum etc. --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > >With the greatest respect, how can a connection >between two dissimilar metals not eventually fail? At 10:32 AM 4/13/2004 -0700, you wrote: >--> AeroElectric-List message posted by: "Rob Housman" > >It's really quite simple. Thermal expansion and contraction of a wire >within a crimped connection is not sufficient to exceed the elastic limit of >the surrounding metal (meaning that there is no permanent deformation). >Because there is no permanent change in size of the metal surrounding the >wire the connection between the two remains air tight at all times. The >same applies to the copper cladding over aluminum. Rob, thank you for the illumination of "simple ideas" that support the premise of permanency of gas-tight crimps on aluminum. I hadn't considered the dynamics necessary to open a gap the terminal's grip. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:29:34 AM PST US From: "flyv35b" Subject: Re: AeroElectric-List: A panel full of displays . . . --> AeroElectric-List message posted by: "flyv35b" > With all due respect...... how many of us have a had a battery failure? I > cannot believe that some of you intend medium to hard IFR with some of our > homebuilts. First consider empennage, wing and prop anti icing equipment > first.... Then I'll believe you need all the rest of the equipment. > > One battery will due if it is the proper quality..... I agree. I've been flying for 40 years and owned probably 20 planes during that time and have never had a battery failure or even heard of one (I am A&P/IA). And most of the time the battery gives plenty of warning that it is about to fail or already has per Bob's definition. I see a battery failure risk as being almost totally negligible in comparison to other IFR flying risks. Cliff ----- Original Message ----- From: "Dale Martin" Subject: Re: AeroElectric-List: A panel full of displays . . . > --> AeroElectric-List message posted by: "Dale Martin" > > With all due respect...... how many of us have a had a battery failure? I > cannot believe that some of you intend medium to hard IFR with some of our > homebuilts. First consider empennage, wing and prop anti icing equipment > first.... Then I'll believe you need all the rest of the equipment. > > One battery will due if it is the proper quality..... > > Just my opinion, > > Dale Martin > Lewiston, ID > LEZ-235 > > > ----- Original Message ----- > From: > To: > Subject: Re: AeroElectric-List: A panel full of displays . . . > > > > --> AeroElectric-List message posted by: czechsix@juno.com > > > > > > Walter, > > > > The main thing I'd consider is that your single battery is a single point > failure for the whole system. I had planned to go the same route as you and > ended up settling on dual battery, single alternator. This gives up the > advantage of having unlimited juice in case of alternator failure, but is > more robust from the perspective of keeping the essentials going. It's also > cheaper than the SD-8, doesn't extract any engine power, and in my case is > even a bit lighter since my aux battery is small. If you wanted to keep the > benefits that the SD-8 offers, but want to eliminate the chances (however > small) of losing everything due to battery (or battery lead) failure, I'd > add at least a small aux battery that can be isolated from the main battery, > such that you have the SD-8 tied to the aux, and the main alternator tied to > the main battery. Then you have true full redundancy and can fly hard IFR > with no limitations imposed by any single failure. > > > > Just my humble .02 > > > > --Mark Navratil > > Cedar Rapids, Iowa > > RV-8A N2D fwf stuff these days... > > > > -------------------------------------------- > > > > From: Walter Tondu > > Subject: Re: AeroElectric-List: A panel full of displays . . . > > > > > > > > Since this is an all-electric airplane I plan on two alternators > > and a single battery with Battery, Essential and Primary buses. > > > > > > > > I hate to ask this, but because this is a forum of intelligent > > people, here goes; > > > > Can you make a case where this would not work? And if so > > what would you change. > > > > (Go easy on me, please) > > -- > > Walter Tondu > > http://www.tondu.com/rv7 > > > > > > ________________________________ Message 7 _____________________________________ Time: 07:31:42 AM PST US From: F1Rocket@comcast.net Subject: Re: AeroElectric-List: Endurance Bus --> AeroElectric-List message posted by: F1Rocket@comcast.net Thanks to everyone who answered my questions. I realized after I'd built my switch panels that even though I had three independent gyro systems in my panel, I had designed in a single point of failure for all of them. I had concentrated too much on the endurance bus from the persective of reducing load during alternator failure and missed the valuable benefit of it providing an alternate feed path from the battery to my filght instruments. I reasoned away the need for the endurance bus because I have dual alternators As designed today, a battery contactor or master switch failure would have rendered my EFIS, A/P, and electric AH all useless because I left off the endurance bus. Now, I plan to move all my radios/gyros to the endurance bus and I will add a switch to my panel to power it. That switch will also serve to power the radios only before start-up for clearance/ATIS/weather etc. My endurance bus is "really" an avionics bus, but I promise not to call it that. Randy F1 Rocket (RV-6 and Long-EZ using Bob's methods) http://f1rocket.home.comcast.net/ > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > At 05:41 PM 4/14/2004 -0500, you wrote: > >--> AeroElectric-List message posted by: "Randy Pflanzer" > > > > > >Using Bob's current wiring diagrams, is it okay to have both the master > >switch and endurance bus switch on at the same time? I assume the diode > >between the two buses keeps things from shorting out. Is there any > >long-term consequence to running with both switches on all the time? It > >doesn't appear so to me, but I'm not always very good at keeping all the > >smoke inside the wires. > > Nope, you can run with the e-bus alternate feed switch on all the time > and it doesn't hurt anything. Be sure to turn it off with all other > switches at shutdown. > > Bob . . . > > > > > > ________________________________ Message 8 _____________________________________ Time: 08:20:37 AM PST US From: Dave Morris Subject: Re: AeroElectric-List: Coaxial Lengths --> AeroElectric-List message posted by: Dave Morris Your friend was either a novice or was building special antennas. The only reason to measure coax is if you're using the coax as an impedance matching section. Other than that, one of the key benefits of coax versus open feedline is that you can cut it to any length to wrap around obstacles. The higher you go in frequency, the higher the losses for longer pieces, so don't coil up 100 feet of coax if 10 feet will do, because it will degrade the signal. Other than that, length is of no importance. Dave Morris N5UP At 08:09 AM 4/15/2004 -0500, you wrote: >--> AeroElectric-List message posted by: "David E. Nelson" > > > >Hi Bob, > >Finished reading through the "Antenna" chapter last night. Back in my >pre-teen >days, I used to spend some time with a ham operator that operated in the HF >band. Although I don't remember the equation, I distinctly remember that he'd >measure all his coaxes before cutting and fitting them with connectors. I >seem >to recall that his reasoning for this was so that the coax was a multiple of >the wavelength of the carrier freq. Is this of any relevance to our apps? > >Thanks, > /\/elson > Austin, TX > RV-7A - Waiting on the wings.... > > Dave Morris ________________________________ Message 9 _____________________________________ Time: 09:09:39 AM PST US Subject: AeroElectric-List: Ignitions/Starting From: BFlood@Sauer-Danfoss.com 04/15/2004 11:09:28 AM --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com To all of you with 1 electronic ignition and one mag - I am assuming the remaining mag does not have an impulse coupling. So your starting procedure would be to turn on both the mag and electronic ignition and then start? or just use the electronic ignition for start? Which leads to my next question... how do you handle the key switch? Does it just lock out the starter or do you also disable the electronic ignition to prevent hand propping (if possible) or is there some type of special switch being used to switch off both the mag and electronic ignition? I am planning to have normal switches for the ignitions but a simple key switch for security. So my best idea yet is to have a key switch to lock out the electronic ignition and starter and then separate switches for mag/electronic/start. Essentially the mag could be made hot with only the switch, but then the plane would be hard to start without the impulse coupling. Am I on the right track here? What have you done - Why? Thanks, Bryan ________________________________ Message 10 ____________________________________ Time: 09:38:33 AM PST US From: "GMC" Subject: RE: AeroElectric-List: PS: z-14 common failure point --> AeroElectric-List message posted by: "GMC" Hi Bob You state that you have "seen a lot of these contactors fail" - I am assuming that the normal battery contactor failure modes would be (1) fail to close when turned on, (2) fail to open when turned off, (3) poor conductivity due pitting of contacts (hard starting) - none of which would cause a problem in flight. Are there other battery contactor failure modes (such as drop out) that you have seen that actually did cause a problem in flight, and if so what are they?? Thanks, George in Langley --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" It just occurred to me that this style contactor has been used on SE certified aircraft for about 60 years as a battery contactor. This offers a tens-of-millions flight-hours experience- base. I've seen a lot of these contactors fail . . . haven't seen any catch fire or fault to ground. This same style contactor is used as battery contactor in OBAM aircraft as well. We're continuing to pile up millions of flight hours history on this part in a CONTINUOUS duty application at substantial current values. If there are valid concerns for the failure mode hypothesized then it's going to happen at the battery long before it happens at the crossfeed contactor. Bob . . . _ ________________________________ Message 11 ____________________________________ Time: 11:53:58 AM PST US Subject: Re: AeroElectric-List: Ignitions/Starting From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Hi Bryan, Embedded comments... > --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com > > > To all of you with 1 electronic ignition and one mag - I am assuming the > remaining mag does not have an impulse coupling. Magnetos without impulse coupling (or some other method to retard the spark timing) are not suitable for starting. > So your starting > procedure would be to turn on both the mag and electronic ignition and > then start? or just use the electronic ignition for start? Both of the mags on my O-200 had impulse couplings... So, I used to turn both of them on when starting. Not unusual. Now, with one electronic ignition, I still turn both systems on, as they both properly retard the spark timing for starting. > Which leads > to my next question... how do you handle the key switch? No key switch. Removed. Using 2 toggle switches. > Does it just > lock out the starter or do you also disable the electronic ignition to > prevent hand propping (if possible) My airplane doesn't have a starter. Hand propping is the only way to make it go. Being able to hand prop might be useful, even on airplanes with starters. > or is there some type of special > switch being used to switch off both the mag and electronic ignition? The p-lead on magnetos needs to be disconnected to run, and shorted to not run. Most electronic ignition systems require the oposite conditions, ie they need to have 12V connected in order to run. I believe Klaus offers an option on some of his systems to be able to work with a normal magneto key switch, though he recommends using toggle switches instead. > I > am planning to have normal switches for the ignitions but a simple key > switch for security. Secure from what? Accidental starter engagement or from theft? I don't think a normal key switch provides any protection from either problem. I suppose that a key switch might discourage a joy rider, but I think that's about it. > So my best idea yet is to have a key switch to lock > out the electronic ignition and starter and then separate switches for > mag/electronic/start. Essentially the mag could be made hot with only > the switch, but then the plane would be hard to start without the > impulse coupling. The only way I can think to wire up what you are talking about involves essentially two electrical disconnects for engine ignition. I don't think I would choose to sacrifice in flight reliability to gain on the ground security. For security, as someone (Bob?) suggests, get one of those heavy padded chains with a high quality padlock, and figure-eight it around the propellor. > > Am I on the right track here? What have you done - Why? > > Thanks, > > Bryan > Regards, Matt- N34RD ________________________________ Message 12 ____________________________________ Time: 12:40:28 PM PST US From: "Bartrim, Todd" "'aeroelectric-list@matronics.com'" Subject: AeroElectric-List: Dynon heated AOA pitot now available --> AeroElectric-List message posted by: "Bartrim, Todd" this week for the heated AOA pitot and plans to begin shipping next week. I've ordered mine. I also currently have the PSS AOA system installed so I can do some direct comparisons. S. Todd Bartrim Turbo 13B RX-9endurance C-FSTB http://www3.telus.net/haywire/RV-9/C-FSTB.htm "Imagination is more important than knowledge" -Albert Einstein ________________________________ Message 13 ____________________________________ Time: 02:13:16 PM PST US From: "Dan Checkoway" Subject: Re: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Dan Checkoway" On my RV-7 I have one Slick impulse coupled mag and one LightSpeed Plasma II. From what I understand, the LSE retards to zero (TDC) for starting. So I use both ignition sources at startup and the thing fires on the first blade when cold, first few blades when hot & purged. Whenever starting, I do this (after any required priming is complete): - master switch on battery only (all 3 buses powered on) - mag switch on (impulse coupler enables starting) - Lightspeed switch on (timing retarded to zero for starting) - engage starter After it's running I flip the master up to the "both" (battery + alt) position and check volts/amps. I don't think there would be any harm in going right to the "both" position before starting, but this method helps force me to check volts/amps after turning on the alternator (B&C L40). By the way (off topic), I just want to express more thanks to Bob for all the help during the construction process and for the excellent book. I followed your guidelines and have what sure seems to be reliable, noise-free system. About 35 hours and counting. Now if you happen to have a trick to make my Airflow Performance high-pressure fuel pump consume less power, I'm all ears!! 8-) )_( Dan RV-7 N714D http://www.rvproject.com ----- Original Message ----- From: Subject: AeroElectric-List: Ignitions/Starting > --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com > > > To all of you with 1 electronic ignition and one mag - I am assuming the > remaining mag does not have an impulse coupling. So your starting procedure > would be to turn on both the mag and electronic ignition and then start? or > just use the electronic ignition for start? Which leads to my next > question... how do you handle the key switch? Does it just lock out the > starter or do you also disable the electronic ignition to prevent hand > propping (if possible) or is there some type of special switch being used > to switch off both the mag and electronic ignition? I am planning to have > normal switches for the ignitions but a simple key switch for security. So > my best idea yet is to have a key switch to lock out the electronic > ignition and starter and then separate switches for mag/electronic/start. > Essentially the mag could be made hot with only the switch, but then the > plane would be hard to start without the impulse coupling. > > Am I on the right track here? What have you done - Why? > > Thanks, > > Bryan > > ________________________________ Message 14 ____________________________________ Time: 03:06:18 PM PST US Subject: Re: AeroElectric-List: Re: Architecure Choices From: czechsix@juno.com --> AeroElectric-List message posted by: czechsix@juno.com Bob, I was about to reply but saw that someone else already caught it...you just misread my post. I agree that the SD-8 is a good system and wasn't trying to make a big deal out of cost/weight/engine power savings, which are marginal differences. My main point to the original question was if I saw any potential problems with an IFR machine that uses dual alternators tied to a single battery. Your own advice to me when asking the same questions about a year ago was that dual batteries, single alternator was more RELIABLE especially for dual electronic ignition, but of course you lose the ability to have unlimited duration that you have with the dual alternator, single battery system. --Mark Navratil Cedar Rapids, Iowa RV-8A N2D finishing From: "Richard E. Tasker" Subject: Re: AeroElectric-List: Re: Architecure Choices --> AeroElectric-List message posted by: "Richard E. Tasker" Uuuh, Bob. You read his post wrong. What he said was: >>This gives up the advantage of having unlimited juice . . . >> >> Meaning, he is choosing to use batteries and one alternator - resulting in limited juice. > > . . . unlimited? That must be a really BIG battery. > Likewise. Other than that, your comments are right on. Dick Tasker ________________________________ Message 15 ____________________________________ Time: 03:06:18 PM PST US From: "Sam Hoskins" Subject: RE: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Sam Hoskins" Matt, You say you hand-prop your O-200. So do I, and I just installed a LSE Plasma III. It seems to start hard when the engine is cold. I have high compression pistons and it doesn't seem to go over the next compression stroke very easily, unless I open the throttle wider than I like to. It starts a lot easier if it's hot. Have you had any experience like this? I thought starting was going to be easier, but so far that's not the case. Sam Quickie Q-200 ~ 1,350 hrs. http://home.mchsi.com/~shoskins/index.htm -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt Prather Subject: Re: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Matt Prather" Hi Bryan, Embedded comments... > --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com > > > To all of you with 1 electronic ignition and one mag - I am assuming the > remaining mag does not have an impulse coupling. Magnetos without impulse coupling (or some other method to retard the spark timing) are not suitable for starting. > So your starting > procedure would be to turn on both the mag and electronic ignition and > then start? or just use the electronic ignition for start? Both of the mags on my O-200 had impulse couplings... So, I used to turn both of them on when starting. Not unusual. Now, with one electronic ignition, I still turn both systems on, as they both properly retard the spark timing for starting. > Which leads > to my next question... how do you handle the key switch? No key switch. Removed. Using 2 toggle switches. > Does it just > lock out the starter or do you also disable the electronic ignition to > prevent hand propping (if possible) My airplane doesn't have a starter. Hand propping is the only way to make it go. Being able to hand prop might be useful, even on airplanes with starters. > or is there some type of special > switch being used to switch off both the mag and electronic ignition? The p-lead on magnetos needs to be disconnected to run, and shorted to not run. Most electronic ignition systems require the oposite conditions, ie they need to have 12V connected in order to run. I believe Klaus offers an option on some of his systems to be able to work with a normal magneto key switch, though he recommends using toggle switches instead. > I > am planning to have normal switches for the ignitions but a simple key > switch for security. Secure from what? Accidental starter engagement or from theft? I don't think a normal key switch provides any protection from either problem. I suppose that a key switch might discourage a joy rider, but I think that's about it. > So my best idea yet is to have a key switch to lock > out the electronic ignition and starter and then separate switches for > mag/electronic/start. Essentially the mag could be made hot with only > the switch, but then the plane would be hard to start without the > impulse coupling. The only way I can think to wire up what you are talking about involves essentially two electrical disconnects for engine ignition. I don't think I would choose to sacrifice in flight reliability to gain on the ground security. For security, as someone (Bob?) suggests, get one of those heavy padded chains with a high quality padlock, and figure-eight it around the propellor. > > Am I on the right track here? What have you done - Why? > > Thanks, > > Bryan > Regards, Matt- N34RD ________________________________ Message 16 ____________________________________ Time: 03:13:28 PM PST US From: "Sam Hoskins" Subject: RE: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Sam Hoskins" Bryan It is imperative that any magneto has either a spark retard device (impulse coupling, shower o sparks, etc) or is inoperative while starting. You always want your start timing to be close to 0 deg, TDC. You DON'T want to have an advanced spark when the engine is turning slowly, during the start phase. An advanced spark at slow speeds can cause kickback, which is damaging to starters. Sam -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of BFlood@Sauer-Danfoss.com Subject: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com To all of you with 1 electronic ignition and one mag - I am assuming the remaining mag does not have an impulse coupling. So your starting procedure would be to turn on both the mag and electronic ignition and then start? or just use the electronic ignition for start? Which leads to my next question... how do you handle the key switch? Does it just lock out the starter or do you also disable the electronic ignition to prevent hand propping (if possible) or is there some type of special switch being used to switch off both the mag and electronic ignition? I am planning to have normal switches for the ignitions but a simple key switch for security. So my best idea yet is to have a key switch to lock out the electronic ignition and starter and then separate switches for mag/electronic/start. Essentially the mag could be made hot with only the switch, but then the plane would be hard to start without the impulse coupling. Am I on the right track here? What have you done - Why? Thanks, Bryan ________________________________ Message 17 ____________________________________ Time: 03:15:04 PM PST US Subject: Re: AeroElectric-List: A panel full of displays . . . From: czechsix@juno.com --> AeroElectric-List message posted by: czechsix@juno.com Hi Dale, To answer your question, very few of us have had battery failure. It's pretty rare, and many people may be comfortable with a single battery in an all-electric airplane (i.e. dual elec. ignition and IFR panel with no vacuum). Personally, I'm NOT comfortable with having all that at stake in a single battery. There have been a few battery failures reported here on this List over the past few years I've followed it, and several people I've talked to have had it happen in cars. I'm talking catastrauphic failure, where the lead or post breaks off, or something happens to the battery itself rendering the whole electrical system dead. I know, I know...they were probably poorly designed installations and/or poorly maintained, and if you have a well-designed installation without stressing the battery leads/terminals, with an RG battery rotated out every other year, the odds of failure are probably reduced to very slim. But in my case I decided to go with a small aux battery to k eep my second ignition alive in the ulikely event that it's needed. Each person can decide for their airplane and mission what they're comfortable with. --Mark Navratil Cedar Rapids, Iowa RV-8A N2D finishing... From: "Dale Martin" Subject: Re: AeroElectric-List: A panel full of displays . . . --> AeroElectric-List message posted by: "Dale Martin" With all due respect...... how many of us have a had a battery failure? I cannot believe that some of you intend medium to hard IFR with some of our homebuilts. First consider empennage, wing and prop anti icing equipment first.... Then I'll believe you need all the rest of the equipment. One battery will due if it is the proper quality..... Just my opinion, Dale Martin Lewiston, ID LEZ-235 ________________________________ Message 18 ____________________________________ Time: 04:26:14 PM PST US Subject: RE: AeroElectric-List: Ignitions/Starting From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Hi Sam, I have stock pistons in my O-200. It was pretty easy to start with 2 mags, and somewhat easier to start with the swapout to an LSE and a mag. Mine is easier to start when its cold, but only because it is pretty easy to flood when hot. Does your carb have an accelerator pump or primer? The way I start mine when cold is to pump the throttle (not primer equipped) 2-3 times. Then, with all of the switches off, pull 4 blades through. All switches on, and it ALMOST always starts on the first pull. When hot, the easiest starting is had by shutting down via the ignition switch, not the mixture control. When ready to go, switches on, and it usually starts again on the first pull. If I shut down via mixture and have to restart, I usually give it about a half pump on the throttle, switches hot, and then most of the time it runs on the 2nd pull. I am not sure what I would do different if I had hi compression pistons. I'll have to think about that. Does the engine fire once but not make it through to the next stroke? Or does it not spark at all? Do you have the prop 'clocked' to a position where you can get a good hard flip on it? Regards, Matt- N34RD > --> AeroElectric-List message posted by: "Sam Hoskins" > > > Matt, > You say you hand-prop your O-200. So do I, and I just installed a LSE > Plasma III. It seems to start hard when the engine is cold. I have > high compression pistons and it doesn't seem to go over the next > compression stroke very easily, unless I open the throttle wider than I > like to. It starts a lot easier if it's hot. > Have you had any experience like this? I thought starting was going to > be easier, but so far that's not the case. > Sam > Quickie Q-200 ~ 1,350 hrs. > http://home.mchsi.com/~shoskins/index.htm > ________________________________ Message 19 ____________________________________ Time: 05:35:54 PM PST US From: "Pat Hatch" Subject: Re: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Pat Hatch" Dan, one other reason to stay in the battery-only position prior to start is that in BOTH you are supplying about 2-3 amps to the alternator field circuit, which is robbing power from your starter. I think it prolongs the life of your battery too to not load it down more than neccessary during a start. On my RV-4 the ammeter happens to be on the battery so you can actually see the 2-3 amps kick in when going to BOTH on the master switch. You probably knew this, but it might help someone else who might not. Pat Hatch RV-4 RV-6 RV-7 Finishing Kit Vero Beach, FL ----- Original Message ----- From: "Dan Checkoway" Subject: Re: AeroElectric-List: Ignitions/Starting > --> AeroElectric-List message posted by: "Dan Checkoway" > > On my RV-7 I have one Slick impulse coupled mag and one LightSpeed Plasma > II. From what I understand, the LSE retards to zero (TDC) for starting. So > I use both ignition sources at startup and the thing fires on the first > blade when cold, first few blades when hot & purged. > > Whenever starting, I do this (after any required priming is complete): > > - master switch on battery only (all 3 buses powered on) > - mag switch on (impulse coupler enables starting) > - Lightspeed switch on (timing retarded to zero for starting) > - engage starter > > After it's running I flip the master up to the "both" (battery + alt) > position and check volts/amps. I don't think there would be any harm in > going right to the "both" position before starting, but this method helps > force me to check volts/amps after turning on the alternator (B&C L40). > > By the way (off topic), I just want to express more thanks to Bob for all > the help during the construction process and for the excellent book. I > followed your guidelines and have what sure seems to be reliable, noise-free > system. About 35 hours and counting. > > Now if you happen to have a trick to make my Airflow Performance > high-pressure fuel pump consume less power, I'm all ears!! 8-) > > )_( Dan > RV-7 N714D > http://www.rvproject.com > > ----- Original Message ----- > From: > To: > Subject: AeroElectric-List: Ignitions/Starting > > > > --> AeroElectric-List message posted by: BFlood@Sauer-Danfoss.com > > > > > > To all of you with 1 electronic ignition and one mag - I am assuming the > > remaining mag does not have an impulse coupling. So your starting > procedure > > would be to turn on both the mag and electronic ignition and then start? > or > > just use the electronic ignition for start? Which leads to my next > > question... how do you handle the key switch? Does it just lock out the > > starter or do you also disable the electronic ignition to prevent hand > > propping (if possible) or is there some type of special switch being used > > to switch off both the mag and electronic ignition? I am planning to have > > normal switches for the ignitions but a simple key switch for security. So > > my best idea yet is to have a key switch to lock out the electronic > > ignition and starter and then separate switches for mag/electronic/start. > > Essentially the mag could be made hot with only the switch, but then the > > plane would be hard to start without the impulse coupling. > > > > Am I on the right track here? What have you done - Why? > > > > Thanks, > > > > Bryan > > > > > > ________________________________ Message 20 ____________________________________ Time: 07:35:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:35 PM 4/15/2004 -0400, you wrote: >--> AeroElectric-List message posted by: "Pat Hatch" > >Dan, one other reason to stay in the battery-only position prior to start is >that in BOTH you are supplying about 2-3 amps to the alternator field >circuit, which is robbing power from your starter. I think it prolongs the >life of your battery too to not load it down more than neccessary during a >start. On my RV-4 the ammeter happens to be on the battery so you can >actually see the 2-3 amps kick in when going to BOTH on the master switch. >You probably knew this, but it might help someone else who might not. This use to be the standard advice on certified ships that it was good practice to leave the alternator and other things OFF during cranking to "save the battery". In the grand scheme of things, adding a few percent more load to a 200+ amp cranking event doesn't have much influence on battery life. Keeping the engine tuned and developing techniques that get the fires lit in a few blades is more beneficial than shaving a few amps of total loads. > > > > Now if you happen to have a trick to make my Airflow Performance > > high-pressure fuel pump consume less power, I'm all ears!! 8-) What are the physics of your pump operation? I designed a pump controller about 20 years ago for a pump that was originally designed to deliver constant pressure to an engine by means of a relief valve. During periods of low fuel flow, the relief valve cracked and ported excess flow back to tank. Simple system but use max power under all fuel flow conditions. By adding an accumulator/transducer combination downstream of the pump, power to the pump motor was throttled to maintain constant pressure at any flow. Result was very low power consumption at low fuel flows and max power needed only during full-rich, max throttle climbs. Cut power consumption by about half for most operations and increased pump brush life by three or four times. Bob . . . ________________________________ Message 21 ____________________________________ Time: 07:57:28 PM PST US From: "Sam Hoskins" Subject: RE: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Sam Hoskins" Matt, I have been hand-propping this aircraft for 15 years, and probably have as many starts as hours. Probably 1,330+ I have an MA3 carb, plus a primer to the intake spider manifold. Both seem to do the same. I start mine much like you do, however with the substitution of the Plasma III starting seems to have gotten harder. It doesn't like to make it over the compression stroke after I release the blade. I attribute that to the high compression pistons, but it has gotten worse with the LSE. Sam -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt Prather Subject: RE: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Matt Prather" Hi Sam, I have stock pistons in my O-200. It was pretty easy to start with 2 mags, and somewhat easier to start with the swapout to an LSE and a mag. Mine is easier to start when its cold, but only because it is pretty easy to flood when hot. Does your carb have an accelerator pump or primer? The way I start mine when cold is to pump the throttle (not primer equipped) 2-3 times. Then, with all of the switches off, pull 4 blades through. All switches on, and it ALMOST always starts on the first pull. When hot, the easiest starting is had by shutting down via the ignition switch, not the mixture control. When ready to go, switches on, and it usually starts again on the first pull. If I shut down via mixture and have to restart, I usually give it about a half pump on the throttle, switches hot, and then most of the time it runs on the 2nd pull. I am not sure what I would do different if I had hi compression pistons. I'll have to think about that. Does the engine fire once but not make it through to the next stroke? Or does it not spark at all? Do you have the prop 'clocked' to a position where you can get a good hard flip on it? Regards, Matt- N34RD > --> AeroElectric-List message posted by: "Sam Hoskins" > > > Matt, > You say you hand-prop your O-200. So do I, and I just installed a LSE > Plasma III. It seems to start hard when the engine is cold. I have > high compression pistons and it doesn't seem to go over the next > compression stroke very easily, unless I open the throttle wider than I > like to. It starts a lot easier if it's hot. > Have you had any experience like this? I thought starting was going to > be easier, but so far that's not the case. > Sam > Quickie Q-200 ~ 1,350 hrs. > http://home.mchsi.com/~shoskins/index.htm > ________________________________ Message 22 ____________________________________ Time: 09:21:08 PM PST US From: "Dan Checkoway" Subject: Re: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Dan Checkoway" > > > Now if you happen to have a trick to make my Airflow Performance > > > high-pressure fuel pump consume less power, I'm all ears!! 8-) > > What are the physics of your pump operation? I designed a pump controller > about 20 years ago for a pump that was originally designed to deliver > constant pressure to an engine by means of a relief valve. During > periods of low fuel flow, the relief valve cracked and ported > excess flow back to tank. Simple system but use max power under > all fuel flow conditions. By adding an accumulator/transducer > combination downstream of the pump, power to the pump motor > was throttled to maintain constant pressure at any flow. Result > was very low power consumption at low fuel flows and max power > needed only during full-rich, max throttle climbs. > > Cut power consumption by about half for most operations and > increased pump brush life by three or four times. That sure sounds good to me. I'm not too familiar with the inner workings of the AFP pump & bypass valve setup, but I have to assume it's roughly the first setup you described above (constant pump operation at full blast + relief valve). I do have a fuel flow transducer downstream of the pump, of course in use & wired to my ACS2002 monitor. Not sure if that could do double duty, or how complex the "throttle" circuit would be. I don't have the knowledge or skills to design something like this on my own, but if you're aware of a simple, affordable method I'd love to learn about it. Even if the final answer ends up being that I just live with what I've got, I'm still interested in finding out about alternatives for fun. Thanks, )_( Dan ________________________________ Message 23 ____________________________________ Time: 09:43:59 PM PST US From: "Terry Watson" Subject: RE: AeroElectric-List: Ignitions/Starting --> AeroElectric-List message posted by: "Terry Watson" I am quite sure I remember a few months ago we were talking on this list about the idea that the Airflow Performance fuel pump is actually usually just a back-up to the engine driven mechanical pump; that unless something goes wrong with the engine driven pump, the Airflow Performance pump is turned on during takeoff and landing only as a safety precaution in case the mechanical pump fails during those critical times. I think Eric had or offered to design a fuel pump switch that would only turn the boost pump on if the fuel pressure dropped, or if the switch was put in the on regardless position. In other words, it would always be ready to turn on if needed but would not normally be running during takeoff and landing unless the pilot chose the override position. So, it would seem the best way to make the pump consume less power would be to use a switch like Eric suggested, leaving the pump off unless it was actually needed to create the needed fuel pressure. Do I remember this right? Terry --> AeroElectric-List message posted by: "Dan Checkoway" > > > Now if you happen to have a trick to make my Airflow Performance > > > high-pressure fuel pump consume less power, I'm all ears!! 8-) >