AeroElectric-List Digest Archive

Tue 05/08/07


Total Messages Posted: 20



Today's Message Index:
----------------------
 
     1. 06:12 AM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Ken)
     2. 07:21 AM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Robert L. Nuckolls, III)
     3. 08:48 AM - Broken Battery (Charles Brame)
     4. 11:28 AM - Belden Triax vs. Coax rg58 (Dave S)
     5. 12:04 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Ernest Christley)
     6. 12:12 PM - Re: Belden Triax vs. Coax rg58 (Ron Quillin)
     7. 01:11 PM - Re: Belden Triax vs. Coax rg58 (Matt Prather)
     8. 02:50 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Peter Harris)
     9. 04:23 PM - Odessesy Bats (Chuck Jensen)
    10. 04:51 PM - Re: Odessesy Bats (Robert L. Nuckolls, III)
    11. 05:00 PM - Re: Wiring integrity!!! (Frank Stringham)
    12. 05:02 PM - Re: Low Voltage Light Flashing (Duane Bentley)
    13. 05:08 PM - Re: Odessesy Bats (Chuck Jensen)
    14. 06:27 PM - Switch confusion (Christopher Barber)
    15. 07:11 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Robert L. Nuckolls, III)
    16. 07:36 PM - Re: Two Txrs on one antenna (Todd Heffley)
    17. 07:56 PM - Re: Odessesy Bats (Mike)
    18. 09:06 PM - Re: Switch confusion (Peter Harris)
    19. 09:32 PM - Re: BASIC DUAL INDEPENDENT POWER SUPPLY (Peter Harris)
    20. 10:50 PM - Re: Wiring integrity!!! (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 06:12:45 AM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: BASIC DUAL INDEPENDENT POWER SUPPLY
    With my belt drive dynamo I feel that the regulator is not really a weak point in the system compared to the belt, bearings, wiring, etc. However with a Jabiru that has I think a direct drive dynamo, would there be any value in having a second regulator that could be manually connected to the battery or the e-bus? Regulator failures do seem to happen much more often than dynamo failures. Personally I'd be content with Z-21 as it is probably more reliable than his EFI system, but Peter seems reluctant to just rely on battery power for extended endurance after an alternator failure. A second regulator is light and wouldn't necesarilly need OV protection if switched in manually. However it would only cater to a regulator problem and wouldn't help if the dynamo quit... I should find note 25 for Z-21 as well. I semi followed the discussion on self excitation a few months ago but it is not obvious to me how the two resistors and diode achieve self excitation when I look at Z-21 now. Ken Robert L. Nuckolls, III wrote: > <nuckollsr@cox.net> > > At 07:13 AM 5/5/2007 +1000, you wrote: > >> <peterjfharris@bigpond.com> >> >> Bob, >> The EFI including pump, ECU and injectors together with his main bus >> radio >> and instruments is using 4A according to advice from the guy who >> engineered >> this simple single body TBI system. (I don't have a figure for the >> separate >> ebus draw for the EFI so you would need to discount for radio and >> instruments)I could also run the electronic ignition module and ignition >> coil for additional ebus current I guessed 4A but it would probably >> be less. >> I am using a Bosch HE coil. >> Alternative landing sites are up to 1hr apart. The endurance is 41/2HRS. >> Thanks >> Peter > > > So how much batter-only endurance are you designing for? What > plans are you making for preventative maintenance to make > sure that design goals slip for lack of due diligence in > maintenance? > > Assuming you're considering a battery capacity on the order > of the popular 3 x 6 x 7 inch form-factor, a 4A load on a > new battery will give you just over two hours of operation > assuming that nothing in your system gives up above 10.5 > volts. See: > > http://www.aeroelectric.com/Pictures/Curves/17AH_Capcity_vs_Load.gif > > Here we see that a 17 ah battery will carry 4A for about 3 hours. > > http://www.aeroelectric.com/Pictures/Curves/28AH_12V_Capacity_vs_Load.gif > > To go out for duration of fuel aboard, you'll need to upsize to > the 28 ah critter for an increase to something on the order of > 360 minutes or 6 hours. > > It's my recommendation that you consider z21 posted at: > > http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z21A.pdf > > Stuff needed to keep the engine running should run from > the battery bus and be switched by their own power switches > SEPARATE from DC power management for the rest of the airplane. > You don't need the diodes. A battery does not fail in a manner > that takes the rest of the system down. Tying the alternator > directly to the battery al-la Z13/8 lets you load-shed the > main bus plus contactor and run only battery bus + ebus loads. > Even the e-bus can be shed if desired. > > I presume you're planning on carrying flight-bag backups > for the panel mounted hardware like > > http://www.aeroelectric.com/Pictures/Misc/Failure_Tolerance.pdf > > This architecture meets the design goals of dual supplies > for keeping the engine lit up. > > Bob . . . >


    Message 2


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    Time: 07:21:36 AM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: BASIC DUAL INDEPENDENT POWER SUPPLY
    At 09:05 AM 5/8/2007 -0400, you wrote: > >With my belt drive dynamo I feel that the regulator is not really a weak >point in the system compared to the belt, bearings, wiring, etc. Certainly things that move, flex, need lubrication, and vibrate are victims of certain kinds of stresses and have obvious limitations to service life. Things that don't move and need grease are not immune from their own stresses which can have an effect on service life too. Just because it's "solid state" doesn't mean that it's automatically more likely to outlive any other component of the system. >However with a Jabiru that has I think a direct drive dynamo, would there >be any value in having a second regulator that could be manually connected >to the battery or the e-bus? The key term here is "value". Indeed, a calculation of cost-of-ownership along with a probability study for any particular failure offers the math and statistics junkie an opportunity for a couple-hundred hour high. Adding another regulator increased parts count not only by doubling the number of regulators but adds a switch to select between them which has its own unique failure modes. >Regulator failures do seem to happen much more often than dynamo failures. . . . an anecdotal observation that may be true but to simply add-another-regulator may not be the optimal solution. WHY does the regulator fail? If it had a better heat sink, would it last longer? If it were redesigned slightly, would it last longer? Until one knows root cause of a failure, the only "remedy" is to play swap-tronics . . . add-a-spare, change brands, etc. It may be comforting from the neophyte's perspective but in fact could have no useful effect on probability of avoiding a sweaty experience while airborne. > Personally I'd be content with Z-21 as it is probably more reliable than > his EFI system, but Peter seems reluctant to just rely on battery power > for extended endurance after an alternator failure. I don't read that into his words. His question was to identify a methodology for crafting "dual, independent power supply". His original notion was that diodes were necessary to acquire independence . . . which is not the case. Moving the alternator feed from bus to battery side of the contactor covers the issues for a failed battery contactor. > A second regulator is light and wouldn't necesarilly need OV protection > if switched in manually. However it would only cater to a regulator > problem and wouldn't help if the dynamo quit... The dynamo is wire wound around a stack of laminations with no moving parts. If these things quit, then it's because a wire broke. That's an exceedingly rare event unworthy of worry. >I should find note 25 for Z-21 as well. I semi followed the discussion on >self excitation a few months ago but it is not obvious to me how the two >resistors and diode achieve self excitation when I look at Z-21 now. It' provides a high source impedance "leakage" around SCR's internal to the regulator such that the rectifier/ regulator is never completely shut down. This causes output from a dynamo to keep a low voltage charge on the output filter capacitor sufficiently elevated to keep the regulator's control circuits from shutting down. Note 25 is a general note for Appendix Z found on page Z-11 of http://aeroelectric.com/articles/Rev11/AppZ_R11J.pdf The foundation for this exchange rests solidly on the notion that a WELL MAINTAINED battery is the most reliable source of energy aboard the aircraft. Of course one strives to reduce likelihood of charging system failure . . . but this is ALWAYS best achieved by increasing service life of the existing components as opposed to increasing numbers of components. Bob . . .


    Message 3


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    Time: 08:48:38 AM PST US
    From: Charles Brame <chasb@satx.rr.com>
    Subject: Broken Battery
    Bob, Where can I get info on how to do a Cap-Check? What equipment is required? I realize this is pretty basic stuff, but I am clueless. Charlie Brame RV-6A N11CB San Antonio > Cap-check is a capacity test. Something that everyone > who depends on the battery for alternator out, e-bus > support should do. The battery will get replaced before > it fails to crank the engine any more. > > > Bob . . . >


    Message 4


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    Time: 11:28:21 AM PST US
    From: "Dave S" <davesh@techii.com>
    Subject: Belden Triax vs. Coax rg58
    Glasair sells and installs Belden 9222 triax for the tail com antenna and for the wing tip nav antenna. Everyone says rg400 is preferred over rg58, but is the triax a step up from the regular rg58 coax? The triax is installed now for the #1 com tail antenna and nav antenna, but I bought more Belden 9222 triax for transponder, 2nd com, and marker antenna runs, should I scrap it and install rg 400? Thanks, Dave Shiffer


    Message 5


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    Time: 12:04:31 PM PST US
    From: Ernest Christley <echristley@nc.rr.com>
    Subject: Re: BASIC DUAL INDEPENDENT POWER SUPPLY
    > However with a Jabiru that has I think a direct drive dynamo, would > there be any value in having a second regulator that could be manually > connected to the battery or the e-bus? Sometimes redundancy means two pieces of hardware dying at the same time. I installed two hard drives in a RAID configuration on my computer for the sake of redundancy. I found a good deal on 7200RPM IBM drives, so I bought a couple. Ran great for years. Fast and reliable. Then both drives crapped out (technical term) within hours of one another. I lost nearly everything. I noticed the problems with one drive, and the other died before I could finish a backup. The serial numbers were within about 4 units of one another. They lived in the same environment, and fed off the same power supply.


    Message 6


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    Time: 12:12:26 PM PST US
    Subject: Re: Belden Triax vs. Coax rg58
    From: Ron Quillin <rjquillin@gmail.com>
    At 11:24 5/8/2007, you wrote: >Glasair sells and installs Belden 9222 triax for the tail com >antenna and for the wing tip nav antenna. Everyone says rg400 is >preferred over rg58, but is the triax a step up from the regular >rg58 coax? The triax is installed now for the #1 com tail antenna >and nav antenna, but I bought more Belden 9222 triax for >transponder, 2nd com, and marker antenna runs, should I scrap it and >install rg 400? > >Thanks, > >Dave Shiffer Belden 9222 is double shielded coax. Tinned copper conductors and PVC outer jacket RG-400 is double shielded coax. Silver plated copper conductors with FEP Teflon outer jacket. The RG is MIL-17 rated, the 9222 is not. We used RG-400 doing a refurb of a certified A/C, and pulled out all the old PVC cable we could find. Ron Q.


    Message 7


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    Time: 01:11:49 PM PST US
    Subject: Re: Belden Triax vs. Coax rg58
    From: "Matt Prather" <mprather@spro.net>
    I don't think any of these cable types will perform appreciably different for small airplane applications. While the RG400 is more tolerant of high temps, I don't think that's relevent for avionics signaling. The RG400 is supposed to be a bit more flexible than RG58, and since 9222 is triax, I might guess that it's less flexible than RG58. The RF performance of RG58 varies depending which part num you buy. Some of the "Low Loss" cable show somewhat better numbers, particularly at transponder freq. Even so, for the cable run lengths and considering the power output of a healthy transponder, it's not an issue. In any case, if you already have equipment installed using 9222, I'd leave it, and if you have the cable and tools to use it for the rest of the airplane, fine. But, I wouldn't go out and buy tools for installing it. The connectors I saw for 9222 look bulky. Might be a hassle in a cramped space. BTW, Belden lists 9222 as a type of RG58 even though it's triax. BTW2, The RG400 I saw has a double layer braid shield, but since it doesn't have a dielectric between the layers, it's not triax. Regards, Matt- > Glasair sells and installs Belden 9222 triax for the tail com antenna and > for the wing tip nav antenna. Everyone says rg400 is preferred over rg58, > but is the triax a step up from the regular rg58 coax? The triax is > installed now for the #1 com tail antenna and nav antenna, but I bought > more > Belden 9222 triax for transponder, 2nd com, and marker antenna runs, > should > I scrap it and install rg 400? > > Thanks, > > Dave Shiffer > >


    Message 8


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    Time: 02:50:02 PM PST US
    From: "Peter Harris" <peterjfharris@bigpond.com>
    Subject: BASIC DUAL INDEPENDENT POWER SUPPLY
    Bob the true practical value of Z-21 is still sinking in and I have been researching batteries. The experienced advice that I am getting down here is not for Odyssey incidentally because of variable quality and that ties in with a recent post. Sometimes I think that we get suspect product down here because we are a long way from the big market. I have been shown an HGL35-12. I was definitely interested in Ken's original suggestion to consider dual regulators because I had never seen the idea before. I had a regulator failure years ago and with the unprotected Quickie circuit and a Revmaster PM installation with no warning on a 900 NM trip. The battery was almost boiling when I arrived after the second leg of the trip. Scary. No concern for that issue with any of your circuits but it is still in my mind that the regulator is the weakest link in the power supply and may be a candidate for a properly designed duplication? Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, 9 May 2007 1:16 AM Subject: Re: AeroElectric-List: BASIC DUAL INDEPENDENT POWER SUPPLY <nuckollsr@cox.net> At 09:05 AM 5/8/2007 -0400, you wrote: > >With my belt drive dynamo I feel that the regulator is not really a weak >point in the system compared to the belt, bearings, wiring, etc. Certainly things that move, flex, need lubrication, and vibrate are victims of certain kinds of stresses and have obvious limitations to service life. Things that don't move and need grease are not immune from their own stresses which can have an effect on service life too. Just because it's "solid state" doesn't mean that it's automatically more likely to outlive any other component of the system. >However with a Jabiru that has I think a direct drive dynamo, would there >be any value in having a second regulator that could be manually connected >to the battery or the e-bus? The key term here is "value". Indeed, a calculation of cost-of-ownership along with a probability study for any particular failure offers the math and statistics junkie an opportunity for a couple-hundred hour high. Adding another regulator increased parts count not only by doubling the number of regulators but adds a switch to select between them which has its own unique failure modes. >Regulator failures do seem to happen much more often than dynamo failures. . . . an anecdotal observation that may be true but to simply add-another-regulator may not be the optimal solution. WHY does the regulator fail? If it had a better heat sink, would it last longer? If it were redesigned slightly, would it last longer? Until one knows root cause of a failure, the only "remedy" is to play swap-tronics . . . add-a-spare, change brands, etc. It may be comforting from the neophyte's perspective but in fact could have no useful effect on probability of avoiding a sweaty experience while airborne. > Personally I'd be content with Z-21 as it is probably more reliable than > his EFI system, but Peter seems reluctant to just rely on battery power > for extended endurance after an alternator failure. I don't read that into his words. His question was to identify a methodology for crafting "dual, independent power supply". His original notion was that diodes were necessary to acquire independence . . . which is not the case. Moving the alternator feed from bus to battery side of the contactor covers the issues for a failed battery contactor. > A second regulator is light and wouldn't necesarilly need OV protection > if switched in manually. However it would only cater to a regulator > problem and wouldn't help if the dynamo quit... The dynamo is wire wound around a stack of laminations with no moving parts. If these things quit, then it's because a wire broke. That's an exceedingly rare event unworthy of worry. >I should find note 25 for Z-21 as well. I semi followed the discussion on >self excitation a few months ago but it is not obvious to me how the two >resistors and diode achieve self excitation when I look at Z-21 now. It' provides a high source impedance "leakage" around SCR's internal to the regulator such that the rectifier/ regulator is never completely shut down. This causes output from a dynamo to keep a low voltage charge on the output filter capacitor sufficiently elevated to keep the regulator's control circuits from shutting down. Note 25 is a general note for Appendix Z found on page Z-11 of http://aeroelectric.com/articles/Rev11/AppZ_R11J.pdf The foundation for this exchange rests solidly on the notion that a WELL MAINTAINED battery is the most reliable source of energy aboard the aircraft. Of course one strives to reduce likelihood of charging system failure . . . but this is ALWAYS best achieved by increasing service life of the existing components as opposed to increasing numbers of components. Bob . . .


    Message 9


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    Time: 04:23:54 PM PST US
    Subject: Odessesy Bats
    From: "Chuck Jensen" <cjensen@dts9000.com>
    Is the Odessesy PC 680 sufficient to spin an IO 540 (BNC starter)? Chuck Jensen


    Message 10


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    Time: 04:51:58 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Odessesy Bats
    At 07:20 PM 5/8/2007 -0400, you wrote: >Is the Odessesy PC 680 sufficient to spin an IO 540 (BNC starter)? > >Chuck Jensen Absolutely. It's a rare VSLA battery in the 17-20 ah class that won't. I've run tests on 10 a.h. batteries that would crank a competition IO-360 engine for 5 or more hard starting cycles (10+ blades). When they won't it's often traced to other losses in the system such as too small cranking wires and/or drops across contactors. Bob . . . ---------------------------------------- ( IF one aspires to be "world class", ) ( what ever you do must be exercised ) ( EVERY day . . . ) ( R. L. Nuckolls III ) ----------------------------------------


    Message 11


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    Time: 05:00:50 PM PST US
    From: "Frank Stringham" <fstringham@hotmail.com>
    Subject: Re: ectric-List:Wiring integrity!!!
    A Cessna 210 on a flight from San Antonio to Seattle when his distress call said smoke in the cabin. The sad out come was the pilot lost control and crashed near Springville, Utah. Now i know that there are other causes of smoke but it raised my concern of eletrical fires. I am wiring my plane according Z-13/8. Now the question: What are the usual failure points that cause electrical fires? in aircraft wiring systems? I know this is pretty open ended and I must also admit that I haven't done a search yet so if you want to with hold until I have done my home work that is fine but if you have some pearls of wisdom .......please help!!!!!!!!!!!!!! Frank @ SGU RV7A "NDY" Panel / electrical..... _________________________________________________________________ More photos, more messages, more storageget 2GB with Windows Live Hotmail.


    Message 12


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    Time: 05:02:59 PM PST US
    From: "Duane Bentley" <dbentley@fuse.net>
    Subject: RE: Low Voltage Light Flashing
    Situation corrected. I contacted B&C this morning and talked to Tim Hedding. He didn't think either the alternator or regulator were defective and sent me to the troubleshooting guide for the LR3C. Working through the steps under the panel, I traced it down to a blown fuse in the power line to the alt. field, (pin 6) of the regulator. I had put in a 5 amp fuse instead of a breaker and missed this fuse in my check last night. Before installing another one, I ohmed the 2-10 battery/alternator switch but found no shorts. The rest of the troubleshoot guide was followed and all checked out. I restarted the plane and the system charges correctly. I call Tim back and said I couldn't find the short but would replace the switch as a precaution. Tim suggested it was unlikely to be a switch problem and that I may have had a temporary over voltage, which blew the 5 amp fuse and shut the alternator down. He suggested I put in a circuit breaker and check for conditions that may have caused the event, which I will do. Duane Bentley RV6 N515DB 255 hrs.


    Message 13


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    Time: 05:08:19 PM PST US
    Subject: Odessesy Bats
    From: "Chuck Jensen" <cjensen@dts9000.com>
    I hadn't had a problem with the PC 680 yet but I'm replacing a FLA battery with the 680 and it always takes one aback to see the difference in size (not that size matters, mind you), so I expect it'll be good to go. Chuck Jensen Robert L. Nuckolls, III >Is the Odessesy PC 680 sufficient to spin an IO 540 (BNC starter)? > >Chuck Jensen Absolutely. It's a rare VSLA battery in the 17-20 ah class that won't. I've run tests on 10 a.h. batteries that would crank a competition IO-360 engine for 5 or more hard starting cycles (10+ blades). When they won't it's often traced to other losses in the system such as too small cranking wires and/or drops across contactors. Bob . . . ---------------------------------------- ( IF one aspires to be "world class", ) ( what ever you do must be exercised ) ( EVERY day . . . ) ( R. L. Nuckolls III ) ----------------------------------------


    Message 14


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    Time: 06:27:20 PM PST US
    From: "Christopher Barber" <CBarber@TexasAttorney.net>
    Subject: Switch confusion
    Maybe I read it and now am forgetting (and now can't find it), but on the Z-14 drawings the two contactor switches that are called out are three position switches. Why? What are the middle positions suppossed to be used for? What position should be used during flight? I got my Z-14 layout cranking my engine today (my 46th birthday <g> ) and I was tickled to have my Wankle rotary churning over effortlessly (just cranking, not yet ready for starting). However, in my use, swithing the switches all the way up seemed to be what activated the contactors allowing the cranking. Insight to what may be obvious is appreciated. TIA. All the best, Chris


    Message 15


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    Time: 07:11:47 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: BASIC DUAL INDEPENDENT POWER SUPPLY
    At 07:47 AM 5/9/2007 +1000, you wrote: ><peterjfharris@bigpond.com> > >Bob the true practical value of Z-21 is still sinking in and I have been >researching batteries. The experienced advice that I am getting down here is >not for Odyssey incidentally because of variable quality and that ties in >with a recent post. Sometimes I think that we get suspect product down here >because we are a long way from the big market. I have been shown an >HGL35-12. I was definitely interested in Ken's original suggestion to >consider dual regulators because I had never seen the idea before. I had a >regulator failure years ago and with the unprotected Quickie circuit and a >Revmaster PM installation with no warning on a 900 NM trip. The battery was >almost boiling when I arrived after the second leg of the trip. Scary. No >concern for that issue with any of your circuits but it is still in my mind >that the regulator is the weakest link in the power supply and may be a >candidate for a properly designed duplication? The "no sweat" electrical system is one that can tolerate any single failure. You experienced what appears to be a runaway that ran unabated. This produced a second failure which, if allowed to run longer, might have smoked lots of stuff. One can stack redundancy on top of redundancy but in every case you first need to do drill: How can this part fail? Is it preflight detectable? If so, is it on my preflight check list to look? How will I know that it failed while in flight? If failure occurs in flight, is it useful for comfortable termination of flight? If so, what's the plan-b for replacing its usefulness? Finally, the most effective failure mitigation plans include a preventative maintenance program that tracks time in service and/or present degradation of performance so that a replacement is made long before failure. A "Plan-B" for a failed part is best crafted from completely different parts and architecture. For example, hand-helds in the flight bag are totally independent of panel mounted hardware and (assuming batteries have been maintained) can be counted on to function when needed. So, if you've done the homework and preventative maintenance that insures sweat-free termination of flight in spite of a failed regulator then adding a second, switched regulator is not the minimum parts count nor totally independent scenario for plan-b. For example, the Cessna Skymaster and Beech Barons had single regulators driving both alternators in parallel. Someone thought that "twin engine reliability" could be maintained by providing a second regulator that could be switched in to replace a failed main regulator. But suppose a short on the field circuit takes out one regulator. Switching in the standby regulator produces TWO failed regulators. If it were my airplane, Z-21 would be the way to go. If the engine were fitted with dual ECFI systems like the Subaru conversions featured in Z-19, then a second battery provides total separation of power sources for dual engine electronics. Given that your engine is fitted with a single system, then there ARE single points of failure that are not going to go away no matter how many power sources you carry. Hence, I'd be more interested in believing that the ECFI had the reliability of propeller bolts than with stacking on more power sources. Bob . . .


    Message 16


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    Time: 07:36:13 PM PST US
    From: Todd Heffley <list@toddheffley.com>
    Subject: Re: Two Txrs on one antenna
    I support Jet aircraft with these coax relays. They are often the source of intermittant problems. the worst are coax relays that split two transponders to one blade antenna. Higher Frequncy IMHO. My experince leads me to think two working antennas are more valuable than one antenna and one unreliable relay. My opinion is colored by maintenance experience, not building experience. Todd


    Message 17


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    Time: 07:56:12 PM PST US
    From: "Mike" <mlas@cox.net>
    Subject: Odessesy Bats
    I crank a Cont. IO-550 with 10:1 pistons with a PC 680. One year and counting and so far and no problems.. Mike Larkin -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Chuck Jensen Sent: Tuesday, May 08, 2007 4:21 PM Subject: AeroElectric-List: Odessesy Bats Is the Odessesy PC 680 sufficient to spin an IO 540 (BNC starter)? Chuck Jensen "http://www.matronics.com/Navigator?AeroElectric-List"http://www.matroni cs.com/Navigator?AeroElectric-List "http://forums.matronics.com"http://forums.matronics.com -- 11:52 AM -- 11:52 AM


    Message 18


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    Time: 09:06:46 PM PST US
    From: "Peter Harris" <peterjfharris@bigpond.com>
    Subject: Switch confusion
    Chris off topic . Which Wankel are you using. I ran the Norton 95HP rotary for 3 years. Peter _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Christopher Barber Sent: Wednesday, 9 May 2007 11:26 AM Subject: AeroElectric-List: Switch confusion Maybe I read it and now am forgetting (and now can't find it), but on the Z-14 drawings the two contactor switches that are called out are three position switches. Why? What are the middle positions suppossed to be used for? What position should be used during flight? I got my Z-14 layout cranking my engine today (my 46th birthday <g> ) and I was tickled to have my Wankle rotary churning over effortlessly (just cranking, not yet ready for starting). However, in my use, swithing the switches all the way up seemed to be what activated the contactors allowing the cranking. Insight to what may be obvious is appreciated. TIA. All the best, Chris


    Message 19


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    Time: 09:32:39 PM PST US
    From: "Peter Harris" <peterjfharris@bigpond.com>
    Subject: BASIC DUAL INDEPENDENT POWER SUPPLY
    Thanks Bob I am going down that path. And you make a good point about the reliability of the ECU. Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, 9 May 2007 1:11 PM Subject: RE: AeroElectric-List: BASIC DUAL INDEPENDENT POWER SUPPLY <nuckollsr@cox.net> At 07:47 AM 5/9/2007 +1000, you wrote: ><peterjfharris@bigpond.com> > >Bob the true practical value of Z-21 is still sinking in and I have been >researching batteries. The experienced advice that I am getting down here is >not for Odyssey incidentally because of variable quality and that ties in >with a recent post. Sometimes I think that we get suspect product down here >because we are a long way from the big market. I have been shown an >HGL35-12. I was definitely interested in Ken's original suggestion to >consider dual regulators because I had never seen the idea before. I had a >regulator failure years ago and with the unprotected Quickie circuit and a >Revmaster PM installation with no warning on a 900 NM trip. The battery was >almost boiling when I arrived after the second leg of the trip. Scary. No >concern for that issue with any of your circuits but it is still in my mind >that the regulator is the weakest link in the power supply and may be a >candidate for a properly designed duplication? The "no sweat" electrical system is one that can tolerate any single failure. You experienced what appears to be a runaway that ran unabated. This produced a second failure which, if allowed to run longer, might have smoked lots of stuff. One can stack redundancy on top of redundancy but in every case you first need to do drill: How can this part fail? Is it preflight detectable? If so, is it on my preflight check list to look? How will I know that it failed while in flight? If failure occurs in flight, is it useful for comfortable termination of flight? If so, what's the plan-b for replacing its usefulness? Finally, the most effective failure mitigation plans include a preventative maintenance program that tracks time in service and/or present degradation of performance so that a replacement is made long before failure. A "Plan-B" for a failed part is best crafted from completely different parts and architecture. For example, hand-helds in the flight bag are totally independent of panel mounted hardware and (assuming batteries have been maintained) can be counted on to function when needed. So, if you've done the homework and preventative maintenance that insures sweat-free termination of flight in spite of a failed regulator then adding a second, switched regulator is not the minimum parts count nor totally independent scenario for plan-b. For example, the Cessna Skymaster and Beech Barons had single regulators driving both alternators in parallel. Someone thought that "twin engine reliability" could be maintained by providing a second regulator that could be switched in to replace a failed main regulator. But suppose a short on the field circuit takes out one regulator. Switching in the standby regulator produces TWO failed regulators. If it were my airplane, Z-21 would be the way to go. If the engine were fitted with dual ECFI systems like the Subaru conversions featured in Z-19, then a second battery provides total separation of power sources for dual engine electronics. Given that your engine is fitted with a single system, then there ARE single points of failure that are not going to go away no matter how many power sources you carry. Hence, I'd be more interested in believing that the ECFI had the reliability of propeller bolts than with stacking on more power sources. Bob . . .


    Message 20


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    Time: 10:50:32 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: ectric-List:Wiring integrity!!!
    At 05:57 PM 5/8/2007 -0600, you wrote: ><fstringham@hotmail.com> > >A Cessna 210 on a flight from San Antonio to Seattle when his distress >call said smoke in the cabin. The sad out come was the pilot lost control >and crashed near Springville, Utah. > >Now i know that there are other causes of smoke but it raised my concern >of eletrical fires. > >I am wiring my plane according Z-13/8. Now the question: What are the >usual failure points that cause electrical fires? in aircraft wiring systems? This is one of the really BIG problems with 99% of the stories cited with tid-bits of anecdotal info. I've worked accidents with smoke in cabin from blower motors, gas-fired heaters, smoking components within a radio, and a fire in a junction box precipitated by out-of-sequence switching of batteries in a 24-48v cranking system on an MU-2. In every case, pilots got the airplane on the ground but in the MU-2 a post-landing fire trashed the interior (although a technician who worked for me years later in the video business worked on the restoration of the same airplane!). In the few cases where I've been privy to the initial failure of a major system component where the pilots lost control and died, none of them involved smoke in the cabin and all scenarios stretched a pilot beyond his ability to cope with the situation. One was a dual alternator failure on a big piston twin where both alternators had been overhauled by the same shop who rewound stators and failed to powder coat the stacks or install slot liners. The two alternators were overhauled several hundred hours apart from each other but failed within minutes of each other on the same flight . . . in icing IMC. When queried as to how many accidents had been investigated at Beech/RAC/Hawker-Beech wherein an electrical system failure was an initiating or participating event, not one of the gray beards in the department could cite a case. In one case, a soft-fault came close to causing an accident. A C-90 on short final to Clovis NM about 1990 was suddenly stricken with complete disconnect of control in pitch. Elevator forces in wheel went to zero. The pilots did a go around and managed to land safely with power and pitch trim. A teardown revealed a mis-positioned wire bundle under the floorboards where a 40A protected wire for co-pilot's windshield heat had had been rubbing against the elevator cable for some period of time. No smoke, no fire, no flickers in the electrical system, no trips of the 40A breaker. Over the pre-failure interval, megajoules of energy were released in the erosion of steel wires (the copper wire was in pretty good shape . . . this demonstrates why layers of copper are included in the design of safes . . . nearly impossible to penetrate with a cutting torch). >I know this is pretty open ended and I must also admit that I haven't >done a search yet so if you want to with hold until I have done my home >work that is fine but if you have some pearls of wisdom .......please >help!!!!!!!!!!!!!! The best thing I can offer is do a good job installing your equipment. Be ready to shut EVERYTHING but the engine off should you experience a smoke event. But know too that likelihood of an electrical system generated smoke event causing a bad day in the cockpit is exceedingly remote. If you do get a smoke event, keeping your cool is more important than self recriminations for not having anticipated the event or loosing sleep over trying to anticipate it now. I wouldn't worry about it. Bob . . .




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