---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 03/20/03: 35 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:52 AM - Re: intercom question (Robert L. Nuckolls, III) 2. 07:01 AM - Alternator wiring (Robert L. Nuckolls, III) 3. 07:17 AM - Re: 10416 tracy (Robert L. Nuckolls, III) 4. 07:22 AM - D-sub pins substitution? (Robert L. Nuckolls, III) 5. 07:29 AM - Re: GM low oil sensor, bum advise (Robert L. Nuckolls, III) 6. 07:39 AM - Re: Crossover Warning Light (Robert L. Nuckolls, III) 7. 07:56 AM - Re: OV Protection (Robert L. Nuckolls, III) 8. 08:04 AM - Re: Radio Recommendations (Robert L. Nuckolls, III) 9. 08:07 AM - Re: GM low oil sensor, bum advise (Dennis O'Connor) 10. 08:23 AM - Re:intercom question (MikeM) 11. 08:37 AM - Re: Altitude control (Robert L. Nuckolls, III) 12. 08:38 AM - Re: Re: RG battery mounting positions (Robert L. Nuckolls, III) 13. 08:40 AM - Re: GM low oil sensor, bum advise (Matt Prather) 14. 08:41 AM - Figure Z-14 (Scott Bilinski) 15. 08:42 AM - Re: Firewall penetraton for wires (Robert L. Nuckolls, III) 16. 08:46 AM - Re: Firewall penetraton for wires (Robert L. Nuckolls, III) 17. 09:11 AM - Re: runaway, self regulated alternators (Robert L. Nuckolls, III) 18. 09:15 AM - Re: Figure Z-14 (Julia) 19. 09:20 AM - Re: 10415 Ferris (Robert L. Nuckolls, III) 20. 09:32 AM - Re: GM low oil sensor, bum advise (John Rourke) 21. 11:44 AM - Re: GM low oil sensor, bum advise (Ed Holyoke) 22. 01:12 PM - Re: Re:intercom question (Robert L. Nuckolls, III) 23. 02:17 PM - Automation of Alternator Disconnect system (Julia) 24. 02:22 PM - Electrical Noise in aircraft wiring (MikeM) 25. 07:10 PM - Too close to my compass? (Sam Hoskins) 26. 07:37 PM - Re: Firewall penetraton for wires (Ron Triano) 27. 07:37 PM - Re: Automation of Alternator Disconnect system (Robert L. Nuckolls, III) 28. 07:40 PM - Re: Figure Z-14 (Robert L. Nuckolls, III) 29. 07:45 PM - Re: Turn coordinator noise (Robert L. Nuckolls, III) 30. 07:53 PM - Contactor Questions (Robert L. Nuckolls, III) 31. 08:33 PM - Re: exploding Jet-A (Robert L. Nuckolls, III) 32. 08:40 PM - Re: Grounding (Robert L. Nuckolls, III) 33. 08:46 PM - Re: Electrical Noise in aircraft wiring (Robert L. Nuckolls, III) 34. 08:49 PM - Re: Too close to my compass? (Robert L. Nuckolls, III) 35. 09:28 PM - Re: Firewall penetraton for wires (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:52:37 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: intercom question --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 04:43 PM 3/19/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Mike Bourget" > > >Hi all,,, new to the list putting together a Sal 2.3rd mustang. > >ready to do wiring now and I have a question. > >If I use the Icom 200, and I wish to also have a CD player do I need to >install an intercom? Mike, sorry I didn't get back to you sooner on your direct query but Dee and I were out of town since last Friday and where we were going, there wasn't any place to plug a computer into the wall . . . Does the A200 have a true intercom function built in? It's not apparent from the front panel controls in spite of the fact that some of the sales literature I've seen on the net speaks about "intercom capabilities" . . . I suspect this simply means that its headphone output signals are not incompatible with intercom systems. You'll need some form of intercom that features additional audio inputs from other sources like nav receiver, marker beacon, alert tones, etc. in addition to stereo outputs from your music system. This also means that you need to acquire headsets wired for stereo music . . . most are not. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:01:45 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Alternator wiring --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >Hi Bob, > >I have purchased your book along with S-704-1 alternator OV relay and the >crowbar overvoltage module. I am building a Skystar Classic IV with a Rotax >912 engine so I am using your diagram Z-15 as a guide. My question is this: Z15??? or Z16 . . .? >On your diagram you have the alternator master circuit wired through the >main power bus and not the essential bus. It seems to me that with this >setup that a failure of the master contactor would result in a shutdown of >the alternator. Is this correct and if so is there any reason not to >attach the >alternator master circuit to the essential bus? The e-bus is generally not needed unless the alternator has failed in which case it allows you to use battery reserves without the burden of the master relay. Depending on how the regulator is configured, the PM alternator on the Rotax may still deliver useful power to the bus with the battery master relay open so battery master relay operation is not necessarily a requirement for alternator operation . . . Even if it is, what kind of flight operations do you anticipate wherein lose of both battery contactor -AND- alternator presents any kind of a tense scenario? Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:17:36 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: 10416 tracy --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >Amp meter fluctuation and gear green lights go from bright to dim at low >rpms less that 1000 rpms. Overhauled alternator 60amps with new >belt. Problem was before and after alternator/belt exchange. A related >problem with radio transmission. Low engine rpm transmission is load and >clear. Cruise rpm transmission is not clean but scratchy. Help >Aircraft PA28R-200 1970 >John This problem needs to be trouble shot by someone who understands how the system works and how it behaves when the different components are not working. Too many mechanics troubleshoot by substitution . . . keep replacing things starting with their "best guess" until the problem goes away. The symptoms you cite are suggestive of a regulator problem brought on my increased resistance of wiring and components between the regulator and the bus . . . easy to trouble shoot by someone who understands what he is doing . . . but their may be other deficiencies compounding the problem. It's not a terribly difficult thing to do but it's more than I can lead you through in a quick e-mail response. Do you have a mechanic helping you with this? Bob . . . |-------------------------------------------------------| | The man who does not read good books has no advantage | | over the man who cannot read them. | | - Mark Twain | |-------------------------------------------------------| ________________________________ Message 4 _____________________________________ Time: 07:22:31 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: D-sub pins substitution? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >Bob, > >Just wanted to thank you for providing all these great resources. I >purchased the AEC book awhile back and it has been a great reference and >educational while building. I'm pleased that you find the investment useful . . . >With the praise out of the way (smile). If you have time for a question >I'd be grateful (and will pay as well - just tell me where to send the check). > >Here goes - I just purchased an UPS/Apollo GX65 COM/GPS unit and it came >with solid barrel connector pins for the DBxx connectors. Since these >require yet another tool that I'll probably never use again I was >wondering your thoughts of the solid pins versus the ones you describe in >your article at >http://www.aeroelectric.com/articles/matenlok/matenlok.html? Since I have >some of the open type pins from left over hobby projects and the crimper >for them as well, it would be really easy to use them. However, if it's >going to come back and bit me, I'll just spend another $90 and buy the >'damn solid pin MS22520 based crimper'. How about a $44 tool at http://www.aeroelectric.com/Catalog/tools/tools.html#rct-3 If it were my airplane, I only use machined pins in the d-sub connectors. Bob . . . ________________________________ Message 5 _____________________________________ Time: 07:29:18 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: GM low oil sensor, bum advise --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:37 PM 3/17/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Finn Lassen > >Ok, I see. > >Could have been spectacular though: full battery voltage across a switch >no longer fully submerged in oil. Wonder if the flash would have been >enough to ignite the oil? If it were a little bit of oil in a large volume of air, perhaps. You can't ignite a fuel that doesn't also have the right ratio of oxygen to go along with the ignition event. That's what's so bogus about the official story of root-cause for TWA800 . . . If you've ever done explosion proof testing of products you'll know how DIFFICULT it is to get the right ratio for explosive mixture even when your trying to do it right. Any time the fuel is in great excess compared to oxygen, the system is as inert as a rock. Stuff like gunpowder works anytime because the chemical reaction provides its own oxygen in an otherwise closed environment. It's a really neat thing that gasoline and its cousins make such lousy bombs. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:39:01 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Crossover Warning Light --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:52 AM 3/17/2003 -0500, you wrote: >--> AeroElectric-List message posted by: KITFOXZ@aol.com > >In a message dated 3/17/2003 9:24:38 AM Eastern Standard Time, jpack@igs3.com >writes: > > > I would like to put a light on the panel that indicates that the Crossover > > Contactor is on (Dual bat, Dual Alt system). Where should I take the lead > > for the light? > > > > - Jim Figure Z-14 shows just such a light adjacent to the cross-feed contactor control switch. ________________________________ Message 7 _____________________________________ Time: 07:56:14 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OV Protection --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:19 PM 3/15/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Tinnemaha" > >I'm in the (very frustrating) process of designing an electrical system >for my first experimental (Kitfox w/ Lyc O-235): > >I'm confused about over voltage protection devices(for alternators): > > I understand that their basic purpose is to protect the electrical > system if the voltage output gets too high, but isn't that the function > of any other type of cirquit protection device (fuses, breakers, fusible > links)? > I'm planning on installing a 35 amp fusible link between the alternator > and the main bus Fusible link? . . . or ANL series current limiter? What size alternator are you using? . . . which power distribution diagram are you basing your system on? > Does that only protect against over-amperage? I saw the 'crow-bar' > type of OV protection devices from B&C on the web site - does that get > installed between the alternator and the fusible link? . . . proper application of the OVM-14 crowbar ov module is described in every appendix Z power distribution diagram where applicable. >Any comments or clarifications would be helpful The first seven paragraphs of chapter 6 speak to what constitutes "over voltage", where it comes from and how and why it needs to be dealt with in a very specific manner . . . Bob . . . ________________________________ Message 8 _____________________________________ Time: 08:04:00 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Radio Recommendations --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:56 AM 3/15/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Tinnemaha" > >Hello List, > >Thank You (especially Bob Nuckolls) for the responses to my question about >de-rating mini switches a while back......the answers made great sense and >convinced me what a great resource this list is. I will be contributing a >touch of $ to the list soon. > >I am in the process of re-designing the panel for my Kitfox....basically >going to use fuses instead of breakers and changing from a panel mounted >GPS/Com to a comm & a hand held GPS (mainly for economic reasons). Could >You please recommend the Comm & GPS that will give me the best value as >well as the best place to get them? I'm assuming a Terra Comm & Garmin >GPS but recommendations from experienced people will be very helpful. I have been flying exclusively with $100 gps receivers from WalMart now for about 5 years (Garmin GPS310 and close cousins). They do everything I need to do and for a very attractive price. Until this past weekend, I was under the impression that they had problems getting locked onto satellites if you were (1) a long way and/or long time from where the receiver was turned off or (2) moving. Just as an experiment, I held my GPS310 up to the cabin window on an MD80 on way to Seattle last week. The receiver had been turned off weeks ago and 600 miles away. It took the radio less than a minute to figure out where we were (over southern Idaho), how fast we were going (526 mph) and how high we were (31,250'). Truly amazing little machines. Hard to find more bang for the buck. This experiment showed that one doesn't have to have the flight-bag back-up receiver up and running for the duration of the trip. Not planning to replace my stereo 310's any time soon. Will give another one away at my upcoming weekend seminar in Ft. Worth. Bob . . . ________________________________ Message 9 _____________________________________ Time: 08:07:58 AM PST US From: "Dennis O'Connor" Subject: Re: AeroElectric-List: GM low oil sensor, bum advise --> AeroElectric-List message posted by: "Dennis O'Connor" And the center tank that exploded and burned on the ramp in Bahrain in front of cameras and witnesses was bogus also? (I think it was Bahrain - if not feel free to correct the location) Denny ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: GM low oil sensor, bum advise > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 06:37 PM 3/17/2003 -0500, you wrote: > >--> AeroElectric-List message posted by: Finn Lassen > > > >Ok, I see. > > > >Could have been spectacular though: full battery voltage across a switch > >no longer fully submerged in oil. Wonder if the flash would have been > >enough to ignite the oil? > > If it were a little bit of oil in a large volume > of air, perhaps. You can't ignite a fuel that > doesn't also have the right ratio of oxygen to > go along with the ignition event. That's what's > so bogus about the official story of root-cause > for TWA800 . . . > > If you've ever done explosion proof testing of > products you'll know how DIFFICULT it is to get > the right ratio for explosive mixture even when > your trying to do it right. Any time the fuel > is in great excess compared to oxygen, the system > is as inert as a rock. Stuff like gunpowder works > anytime because the chemical reaction provides > its own oxygen in an otherwise closed environment. > It's a really neat thing that gasoline and its > cousins make such lousy bombs. > > Bob . . . > > ________________________________ Message 10 ____________________________________ Time: 08:23:57 AM PST US From: MikeM Subject: AeroElectric-List: Re:intercom question --> AeroElectric-List message posted by: MikeM From: "Mike Bourget" >If I use the Icom 200, and I wish to also have a CD player do I >need to install an intercom? Hi Mike: I have tried to drive stereo aviation headsets (LightSpeeds) from a Sony Discman battery-powered CD player without extra amplification, and it almost works, but not quite. The problem is that the lightweight headphones supplied with the Sony are a much lower impedance (~30 Ohms per ear) than aircraft headsets (~150 Ohms per ear). Since the Sony is powered with just two 1.5V alkaline cells, it is only capable of producing about 2.8V peak to peak of audio signal across 30 Ohms, or open circuit. Now 2.8Vp-p is 1Vrms, meaning that the Sony produces P=E 2/R or (1x1)/30 =33mw per ear. If you substitute a 150 Ohm headset, the voltage out of the Sony stays the same, but the power drops to (1x1)/150 = 7mw. This is just not enough to overcom the ambient noise in the cockpit. The level is just too low, even with the volume control on the headsets, and the Sony running wide open. To drive aviation headsets with the Sony, you need a stereo amplifier which is capable of delivering about 30mw to 150 Ohms. By transposing the above equation, we find that it takes E=sqrt(R*P) or sqrt(0.03*150) = 2.1 Vrms, which is 6Vp-p, which means you need a voltage gain of about 3. There are several ways to get the required voltage gain. Use two transformers, roll your own stereo amp, buy a Muse from PS Engineering (http://www.ps-engineering.com), buy a stereo intercom which contains such an amplifier, or buy an expensive panel-mounted stereo audio switching panel. The problem with audio transformers is availability and bulk. You would need 30Ohm to 150Ohm matching transformer with freq response from 30 Hz to >10000 Hz. These are hard to find. Ones that have good low freq respnse would be fairly big, too. Being cheap, I built a little stereo amp using a single IC audio amp chip. It has a freq response which is flat from 10Hz to 10KHz. It has a fixed gain of 3. It will drive four stereo headsets simultaneouly. The audio quality with the noise-cancelling LightSpeed headsets is HiFi. It automatically mutes the music during intercom or ATC radio activity. I haven't written this up in the form of an article for publication, but might be persuaded to do so... Mike Mladejovsky Skylane '1MM Pacer '00Z ________________________________ Message 11 ____________________________________ Time: 08:37:08 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Altitude control --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:53 AM 3/15/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Kevin Horton > > >--> AeroElectric-List message posted by: "Gary Casey" > > > ><<> I've got plans for > >> a super sensitive, temperature compensated pressure > >> transducer that gives me +/- 20 foot accuracy to > >> 60,000 feet and better than 1% accuracy for pitot > >> pressures to 300 kts. > > > >Does this mean we will be seeing a reasonably accurate, affordable altitude > >control > >device in > >the near future?>> > > > >Pardon me if I don't hold my breath for this one. 20 feet of accuracy at > >60,000 equates to a maximum error of .00098 psi, or 0.007% of full scale, an > >accuracy not attainable by even laboratory grade sensors. At sea level 20 > >feet equates to 0.01 psi or 0.07% of full scale, within reach of high-end > >pressure sensors, but only over a very limited temperature range. I did misquote the spec . . . (which is inexcusable 'cause I wrote it about 8 years ago). Accuracy at altitudes below 20,000 feet was spec'd at 50 feet but the little box easily holds +/- 20 feet for all effects combined. We spec'd accuracy to degrade linearly above 20,000 feet to +/- 1000 feet at 60K . . . the supplier came in at under 300 feet. This isn't a laboratory grade sensor . . . in fact, it's a jelly-bean part that's individually characterized for production variations and temperature effects as part of the normal environmental screening processes. These sensors are not particularly accurate nor are they stable with temperature but they turned out to be quite repeatable. By driving them with a precision constant current source and measuring the voltage drop across the bridge excitation terminals, the sensor becomes its own temperature monitor. Pressure data is, of course, taken off the bridge taps on either side. For altitude control, one can get by with holding current pressure under prevailing conditions with sufficient resolution to meet requirements of the servo model. This used to be done by simply closing off the vent to an aneroid capsule with a valve and then let the capsule drive an lvdt to characterize departures from the pressure captured within the aneroid. That was the technique of choice in 1965 (Cessna Nav-o-Matic 400). Nowadays, one could use a full range absolute sensor with lots of gain (al-la the techniques described above) or a low range differential sensor and capture valve like the ol' Nav-o-Matics. In either case, one could ignore temperature and calibration issues since you're only interested in the short term stability under present conditions. That's what the ez-trim system does as I recall. Bob . . . Bob . . . ________________________________ Message 12 ____________________________________ Time: 08:38:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: RG battery mounting positions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:07 PM 3/14/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Jim Jewell" > >Hello Gary, > >Seek out the Concord Battery site for one. They sell Certified RG sealed >lead acid batteries for Certified aircraft and have done so for some number >of years now. > >Jim in Kelowna > >----- Original Message ----- >From: >To: >Subject: Re: AeroElectric-List: RE: RG battery mounting positions > > > > --> AeroElectric-List message posted by: Aucountry@aol.com > > > > Anyone on this list ever get an RG battery approved in a cerified plane? > > Especially now with the way the FAA is (more) messed up? > > > > Gary B&C has STC's to put several of their battery offerings into certified ships as well. Bob . . . ________________________________ Message 13 ____________________________________ Time: 08:40:18 AM PST US Subject: Re: AeroElectric-List: GM low oil sensor, bum advise From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" > If you've ever done explosion proof testing of > products you'll know how DIFFICULT it is to get > the right ratio for explosive mixture even when > your trying to do it right. Any time the fuel > is in great excess compared to oxygen, the system > is as inert as a rock. Stuff like gunpowder works > anytime because the chemical reaction provides > its own oxygen in an otherwise closed environment. > It's a really neat thing that gasoline and its > cousins make such lousy bombs. > > Bob . . . That's also why its such a challenge to make a fuel efficient carbuerator/ fuel injection system. And why it takes >17kV to make it light, even with the correct mixture. An interesting observation about twa800. Matt- ________________________________ Message 14 ____________________________________ Time: 08:41:30 AM PST US From: Scott Bilinski Subject: AeroElectric-List: Figure Z-14 --> AeroElectric-List message posted by: Scott Bilinski I see everyone referencing Z-this and Z-that.......This is in reference to? Scott Bilinski Eng dept 305 Phone (858) 657-2536 Pager (858) 502-5190 ________________________________ Message 15 ____________________________________ Time: 08:42:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Firewall penetraton for wires --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 05:57 PM 3/14/2003 -0500, you wrote: >--> AeroElectric-List message posted by: Benford2@aol.com > >In a message dated 3/14/2003 12:58:18 PM Mountain Standard Time, >Hebeard2@aol.com writes: > > > > > > > > First of all I couldn't find any stainless steel towel bars, but with the > > help of a sales person I found stainless steel Grab Bars. I couldn't find > > any > > with the stock number given, but they did have quite a selection. Most > were > > > > 1.5" in diameter rather than 1.25". The various stock numbers referred to > > varying finishes available to facilitate good friction when grasping. > There > > > > were some 1.25" diameter in 24" length which cost $33.00. Searching for a > > shorter length, I found an 18" length in 1.5" diameter for $19.96 (Stock # > > 6318, Satin Stainless Steel). Since length means nothing for our purposes, > > and I am cheap, this is the one I bought. I figure the firestop to plug > the > > > > extra .25" wouldn't cost $13.00. Don't get too hung up on stock numbers, > > look > > at the product under Grab Bars. You don't need to use fire-stop putty to fill the excess volume of the larger tubes. Study the pictures posted at http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html The only place you need any sealing is under the flange were it bolts to the firewall. Bob . . . ________________________________ Message 16 ____________________________________ Time: 08:46:43 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Firewall penetraton for wires --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:24 PM 3/14/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Ron Triano" > >Hi Harvey, since I was the one with the stainless towel/ grab bar >suggestion, I am supprised you found a salesman in Home depot that knew >what supplies were in their department. If you happen to be a capable >stainless welder you could just use a piece of tubing with a flange >welded to the end. I am squishing mine with the flange on the firewall >side with fire caulking then over filling the interior of the tube and >wire with the same caulking. The caulking is readilly available in >varying temp's. Do I infer that you're not using fire-sleeve with this installation? Bob . . . ________________________________ Message 17 ____________________________________ Time: 09:11:58 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: runaway, self regulated alternators --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:52 AM 3/14/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > > >Bob > >Thanks for the extended reply. > >However its hard to ignore the melted alternator I had in my hands years >ago. That convinced me that an internal failure could keep the voltage low >enough so the shorted current had time to heat things up and one could not >count on the field acting as a fuse. The theory was a diode failure started >things. >Regardless of our differences I personally would never consider a regulator >that could not be controlled fully. Thus no internal regulator with >connections to the "B" lead. Its just not worth the small cost savings. I'm trying to understand the physics supporting your concerns. It is sufficient to "agree to disagree" in politics but we're talking about differing opinions where you suggest my recommendations offer some potential for fire hazard. My premise is that the action of disconnecting a failed alternator from the bus by means of b-lead disconnect contactor allows the alternator output voltage to rise without restraint offered by any loads or battery. Under these conditions, outputs of over 100 volts are easily realized and the resulting current in the field winding will fuse it in seconds. I've seen LOTS of melted alternators also . . . WITH and WITH0UT external regulators. In every case, destruction of the alternator proceeded within constraints offered by system loads and vehicle's battery. The whole idea of the b-lead disconnect is to encourage timely, uneventful self-destruction of the alternator's internals in a manner that mitigates risks demonstrated countless times when the alternator remains connected to the system. Let's be engineers here and dispel lingering doubts on the part of some who read this list. This is an IMPORTANT discussion Paul. The availability of alternators easily modified for external regulation is low. Availability of off-the- car alternators with stellar track records and built in regulators is high. If we're going to take advantage of what SHOULD be a trend toward utilization of commercial off the shelf products, we need to offer our brothers and sisters good reasons and lucid explanations for our recommendations based on the best engineering we know. Bob . . . ________________________________ Message 18 ____________________________________ Time: 09:15:15 AM PST US From: Julia Subject: Re: AeroElectric-List: Figure Z-14 --> AeroElectric-List message posted by: Julia http://www.aeroelectric.com/Catalog/BCcatalog.html go to the link above and get the aeroconnection book - the 10th addition -it's $30 - it has all the diagrams - and it's good reading - it will open your eyes to many issues involving wiring on airplanes Scott Bilinski wrote:--> AeroElectric-List message posted by: Scott Bilinski I see everyone referencing Z-this and Z-that.......This is in reference to? Scott Bilinski Eng dept 305 Phone (858) 657-2536 Pager (858) 502-5190 --------------------------------- ________________________________ Message 19 ____________________________________ Time: 09:20:41 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: 10415 Ferris --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > Bob: >I'm starting to build a Rans S-12S next month. >These question are on fuses. >1. What are the trip characteristics of the 1-15 amp plug-in fuses on your >website? Are they slow-blow, fast-trip, other? They're stock automotive fast blow fuses. >2. I will have one load that will exceed 15A - a MarinePro 250W 12V cabin >heater. Although the thermostat will adjust power consumption as the cabin >heats up, it could initially draw over 20 amps. How would you recommend >that I protect the wiring to it? >Derek A 250 watt heater in a Rans cabin is like trying to heat your garage with a Bic lighter. People have installed electric heaters in airplanes like the Long-Ez . . . had one builder go for a 60A, 28v system in his Ez so he could have sufficient excess watts to use for cabin heat. Even then, the pair of 700 watt heaters were little more than toe warmers. Have you talked with any other Rans owners who have installed this heater in their airplane? The 250 W heater will draw just under 20A, more than the total energy produced by your alternator (I presume you're using a Rotax 912). Believe me, the thermostat on this heater wont shut the heat off before late spring. Bob . . . ________________________________ Message 20 ____________________________________ Time: 09:32:07 AM PST US From: John Rourke Subject: Re: AeroElectric-List: GM low oil sensor, bum advise --> AeroElectric-List message posted by: John Rourke I believe you are referring to a 737 in Manila in May 1990? Although explosive residue was not found, the possibility remains - I read a report where the passenger decking being pushed upwards was claimed to not be consistent with a fuel-tank explosion... but I haven't read much on it, just wanted to mention that the root cause of that one is still debated. No other fuel-tank explosions are known in 80 years of airline recordkeeping, according to the same reports. -John R. Dennis O'Connor wrote: > --> AeroElectric-List message posted by: "Dennis O'Connor" > > And the center tank that exploded and burned on the ramp in Bahrain in front > of cameras and witnesses was bogus also? > (I think it was Bahrain - if not feel free to correct the location) > > Denny > ----- Original Message ----- > From: "Robert L. Nuckolls, III" > To: > Subject: Re: AeroElectric-List: GM low oil sensor, bum advise > > > >>--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > >>At 06:37 PM 3/17/2003 -0500, you wrote: >> >>>--> AeroElectric-List message posted by: Finn Lassen >> > > >>>Ok, I see. >>> >>>Could have been spectacular though: full battery voltage across a switch >>>no longer fully submerged in oil. Wonder if the flash would have been >>>enough to ignite the oil? >> >> If it were a little bit of oil in a large volume >> of air, perhaps. You can't ignite a fuel that >> doesn't also have the right ratio of oxygen to >> go along with the ignition event. That's what's >> so bogus about the official story of root-cause >> for TWA800 . . . >> >> If you've ever done explosion proof testing of >> products you'll know how DIFFICULT it is to get >> the right ratio for explosive mixture even when >> your trying to do it right. Any time the fuel >> is in great excess compared to oxygen, the system >> is as inert as a rock. Stuff like gunpowder works >> anytime because the chemical reaction provides >> its own oxygen in an otherwise closed environment. >> It's a really neat thing that gasoline and its >> cousins make such lousy bombs. >> >> Bob . . . >> >> > > > > > > > > > ________________________________ Message 21 ____________________________________ Time: 11:44:26 AM PST US From: Ed Holyoke Subject: RE: AeroElectric-List: GM low oil sensor, bum advise --> AeroElectric-List message posted by: Ed Holyoke Wasn't that in Bangkok? The prime minister was to board the aircraft a couple of hours later. Initial talk was an assassination attempt. Later they said it was the center tank. Ed Holyoke > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner- > aeroelectric-list-server@matronics.com] On Behalf Of Dennis O'Connor > Sent: Thursday, March 20, 2003 8:07 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: GM low oil sensor, bum advise > > --> AeroElectric-List message posted by: "Dennis O'Connor" > > > And the center tank that exploded and burned on the ramp in Bahrain in > front > of cameras and witnesses was bogus also? > (I think it was Bahrain - if not feel free to correct the location) > > Denny > ----- Original Message ----- > From: "Robert L. Nuckolls, III" > To: > Subject: Re: AeroElectric-List: GM low oil sensor, bum advise > > > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > > > > At 06:37 PM 3/17/2003 -0500, you wrote: > > >--> AeroElectric-List message posted by: Finn Lassen > > > > > > >Ok, I see. > > > > > >Could have been spectacular though: full battery voltage across a > switch > > >no longer fully submerged in oil. Wonder if the flash would have been > > >enough to ignite the oil? > > > > If it were a little bit of oil in a large volume > > of air, perhaps. You can't ignite a fuel that > > doesn't also have the right ratio of oxygen to > > go along with the ignition event. That's what's > > so bogus about the official story of root-cause > > for TWA800 . . . > > > > If you've ever done explosion proof testing of > > products you'll know how DIFFICULT it is to get > > the right ratio for explosive mixture even when > > your trying to do it right. Any time the fuel > > is in great excess compared to oxygen, the system > > is as inert as a rock. Stuff like gunpowder works > > anytime because the chemical reaction provides > > its own oxygen in an otherwise closed environment. > > It's a really neat thing that gasoline and its > > cousins make such lousy bombs. > > > > Bob . . . > > > > > > > > > > ________________________________ Message 22 ____________________________________ Time: 01:12:53 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re:intercom question --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:22 AM 3/20/2003 -0700, you wrote: >--> AeroElectric-List message posted by: MikeM > > >From: "Mike Bourget" > > >If I use the Icom 200, and I wish to also have a CD player do I > >need to install an intercom? > >Hi Mike: > >I have tried to drive stereo aviation headsets (LightSpeeds) >from a Sony Discman battery-powered CD player without extra >amplification, and it almost works, but not quite. Mike, a lucid and accurate analysis. Thank you for sharing . . . >Being cheap, I built a little stereo amp using a single IC audio >amp chip. It has a freq response which is flat from 10Hz to >10KHz. It has a fixed gain of 3. It will drive four stereo >headsets simultaneouly. The audio quality with the >noise-cancelling LightSpeed headsets is HiFi. It automatically >mutes the music during intercom or ATC radio activity. > >I haven't written this up in the form of an article for >publication, but might be persuaded to do so... I'd be pleased to publish it on aeroelectric.com . . . Bob . . . ________________________________ Message 23 ____________________________________ Time: 02:17:55 PM PST US From: Julia Subject: AeroElectric-List: Automation of Alternator Disconnect system --> AeroElectric-List message posted by: Julia Bob: any ideas on automating the Alternator disconnect system? Like how about if the Voltage crowbar thingy goes off, it would automatically disconnect the alternator contactor and alternator field? this would also turn on a light to let you know you where running only on the battery? What things would you need to consider in an automated system which took care of this alternator field switch and alternator disconnect switch? --------------------------------- ________________________________ Message 24 ____________________________________ Time: 02:22:55 PM PST US From: MikeM Subject: AeroElectric-List: Electrical Noise in aircraft wiring --> AeroElectric-List message posted by: MikeM I have been reading the aeroelectric forum for a few months. I have noticed that a lot of the discussions have to do with the mechanics of wiring aircraft, i.e crimping vs soldering, wire sizes, ring terminals, etc. Also, there is a lot of discussion about circuit protection, redundency, reliability, spike suppression, etc. Occasionaly, there are a few questions about electrical noise, i.e., shielding, grounding, ground loops, bypassing, filtering, especially where it involves audio, intercoms, mic wiring, audio switching panels, entertainment. Usually, what starts the discussion is something like "how do I get the alternator whine/strobe squeal out of my headphones?" The topic of grounding/shielding is often the least understood, and there is a lot of bad advice that is meted out, here and on other forums. I'll go so far as to say that a lot of avionics vendors, and most avionics installers dont really know what they are doing. I just happened to be poking around at an Intel Microcontroller site, and found the following application note AN-125, which succinctly discusses this topic: http://www.intel.com/design/auto/mcs96/applnots/21031302.PDF "Designing Microcontroller Systems for Electrically Noisy Environments". Read the app note. Study it. There will be a quiz.... Mike Mladejovsky ________________________________ Message 25 ____________________________________ Time: 07:10:25 PM PST US From: "Sam Hoskins" Subject: AeroElectric-List: Too close to my compass? --> AeroElectric-List message posted by: "Sam Hoskins" I am retrofitting my fiberglass aircraft with a B&C 200G alternator and accompanying regulator & filter capacitor. Space behind the panel is at a premium, and it is very difficult to work down there, close to the firewall. I would like to install the voltage regulator right behind the panel, but this location is about 6" forward of my whiskey compass. Do you think this will present a problem and create magnetic interference? If I had my druthers, I would really like to mount it on the forward side of the firewall, but the installation diagram calls for the aft side of the FW. Any comments? Sam Hoskins Quickie Q-200 ~1,375 hours (Friends don't let friends fly metal airplanes). ________________________________ Message 26 ____________________________________ Time: 07:37:42 PM PST US From: "Ron Triano" Subject: RE: AeroElectric-List: Firewall penetraton for wires --> AeroElectric-List message posted by: "Ron Triano" Hi Bob, Just started reading your book, Is (fire Sleave) something I have not got to yet? Not familiar with it. Ron Triano -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Subject: RE: AeroElectric-List: Firewall penetraton for wires --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" --> At 12:24 PM 3/14/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Ron Triano" >--> > >Hi Harvey, since I was the one with the stainless towel/ grab bar >suggestion, I am supprised you found a salesman in Home depot that knew >what supplies were in their department. If you happen to be a capable >stainless welder you could just use a piece of tubing with a flange >welded to the end. I am squishing mine with the flange on the firewall >side with fire caulking then over filling the interior of the tube and >wire with the same caulking. The caulking is readilly available in >varying temp's. Do I infer that you're not using fire-sleeve with this installation? Bob . . . direct advertising on the Matronics Forums. ________________________________ Message 27 ____________________________________ Time: 07:37:53 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Automation of Alternator Disconnect system --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 02:13 PM 3/20/2003 -0800, you wrote: >--> AeroElectric-List message posted by: Julia > > >Bob: > >any ideas on automating the Alternator disconnect system? Like how about >if the Voltage crowbar thingy goes off, it would automatically disconnect >the alternator contactor and alternator field? this would also turn on a >light to let you know you where running only on the battery? > >What things would you need to consider in an automated system which took >care of this alternator field switch and alternator disconnect switch? Not sure if I understand your question but I think it's already automated. Within seconds of an ov tripout, the bus voltage drops below 13.0 volts and your low-voltage warning light begins to flash. Not sure what else is needed here . . . Bob . . . ________________________________ Message 28 ____________________________________ Time: 07:40:31 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Figure Z-14 --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:41 AM 3/20/2003 -0800, you wrote: >--> AeroElectric-List message posted by: Scott Bilinski > > >I see everyone referencing Z-this and Z-that.......This is in reference to? > > >Scott Bilinski >Eng dept 305 >Phone (858) 657-2536 >Pager (858) 502-5190 Appendix Z of the AeroElectric Connection is a growing collection of power distribution diagrams that provide a basis configuring a system to meet your mission needs. Most single engine airplanes produced since the first batteries went on board about 1948 haven't materially advanced in philosophy to this day. The Appendix Z drawings offer a variety of starting points depending on your mission and budget. The drawings are part of the book . . . but since they are updated with every revision to the book, they can also be downloaded as part of the information packages indexed at: http://www.aeroelectric.com/articles.html Bob . . . ________________________________ Message 29 ____________________________________ Time: 07:45:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Turn coordinator noise --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:06 PM 3/18/2003 +0000, you wrote: >--> AeroElectric-List message posted by: "Shay King" > >Dear Bob, >I've installed a cheap turn coordinator in my CH701. It's causing noise >in the headset when intercom on, or when transmitting. No noise when >receiving only. I've looked at some of your suggestions in the archive >and will try some of them tommorrow. > >Is it likely that if I had bought an expensive instrument that it wouldn't >cause noise problems? Several people have experienced the same problem over the years and it seems to always involve a Chinese manufactured instrument. Someone on the list promised me the "carcase" of his purchase should it prove to be a noise problem too. I'll see if I can get my friends out at the RFI lab to look at its noise characteristics. It might be possible to craft a modification and/or filter to mitigate the problem. Bob . . . ________________________________ Message 30 ____________________________________ Time: 07:53:10 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Contactor Questions --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > Bob, need to know which large posts on the S-701-1 OV Disc. The large terminals are interchangeable. The small terminals are also except that the diode polarity determines which terminal gets (+) voltage. >Contactor does the "b" lead from Alt. fasten (Bat post or other post) on >Z-24 11/01? Also, which small post does the "F" and Alt. Fld. 5 Amp wires >(20AWG) fasten to or does it matter?? This contactor has a diode from the >Bat.post to the first small post on the right- horizontally. This post >has two more diodes also - (one to the next small post to the right and >one that fastens to the other large post not identified). If you truly have an S701-1 contactor it should have been sent to you looking like this: http://www.aeroelectric.com/Catalog/switch/s701-1l.jpg Either fat terminal can be wired to the alternator with the other one going to starter contactor. You would REMOVE the red jumper wire visible in on the left side of the picture. Small terminal on right goes to ground, small terminal on left goes to your field switch. What you've described has three diodes and probably looks like this: http://www.aeroelectric.com/Catalog/switch/s701-2.jpg This is the S701-2 contactor supplied with extra diodes to serve as a cross-feed contactor in Z-14. If this is what you have, then remove two diodes wired to each fat terminal and then wire as described for the -1 contactor above. Bob . . . ________________________________ Message 31 ____________________________________ Time: 08:33:59 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: exploding Jet-A --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:16 PM 3/20/2003 -0600, you wrote: >--> AeroElectric-List message posted by: John Rourke > > >I believe you are referring to a 737 in Manila in May 1990? > >Although explosive residue was not found, the possibility remains - I >read a report where the passenger decking being pushed upwards was >claimed to not be consistent with a fuel-tank explosion... but I haven't >read much on it, just wanted to mention that the root cause of that one >is still debated. > >No other fuel-tank explosions are known in 80 years of airline >recordkeeping, according to the same reports. > >-John R. >Dennis O'Connor wrote: > > --> AeroElectric-List message posted by: "Dennis O'Connor" > > > > > And the center tank that exploded and burned on the ramp in Bahrain in > front > > of cameras and witnesses was bogus also? > > (I think it was Bahrain - if not feel free to correct the location) There has been an exhaustive study of public data on the TWA800 incident. I've read quite a bit of it with particular interest discussions illuminated with logic and good physics. Like all such cases, there are plenty of "fog generators" in the discussion including conspiracy theorists and (not the least of which) are agencies of government with competing agendas. The tank in question had to have unusable and/or unused liquid fuel in it. I am mystified as to how the vapor-space in any closed volume with liquid in the bottom, dilutes what would normally be a nearly saturated mixture of fuel/air down to a stoichiometric ratio required for combustion with a high release of energy with any fuel, much less Jet-A. This is but ONE of many questions which I find puzzling. You're free to evaluate for yourself. There are many reasons to be suspicious of the engineering and investigative techniques . . . but be prepared to spend some time looking through the details. check out www.twa800.com http://home.earthlink.net/~neteagle/ Here's but one of many examples of logical, detailed and independent analysis to be found with a bit of websearching . . . http://www.compassionateweb.net/~missiletwa800/mann.htm and as a tip of the iceberg . . . http://www.worldnetdaily.com/news/article.asp?ARTICLE_ID=24075 http://twa800.com/news/Stalcup.htm http://www.flight800.org/sketch.htm http://www.multipull.com/twacasefile/second649.html http://twa800.com/images/exhibit22c_radar.pdf It's a complex puzzle but in the final analysis, only the RIGHT pieces fit together into the real picture. I've found the reasoning of a number of folks to be compelling and in direct contradiction with the officially published accounts. If you feel compelled to learn and/or enjoy putting big puzzles together one could do worse than study what's out there on TWA800. Bob . . . ________________________________ Message 32 ____________________________________ Time: 08:40:15 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Grounding om> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:07 PM 3/20/2003 -0700, you wrote: >Bob, > > >> Single ground blocks are shipped with with a shorter brass carry >through bolt, washers and nuts for sheet metal firewalls. If in doubt as >you your grounding needs, drop us an e-mail note. > >Getting ready to order some items off your website (what an awesome >resource) and had an electric ground related question. I'm building a >Zodiac 601HDS with a Subaru EA81 (engine mounted up front w/ starter, >low wing, all metal) and will have the battery installed behind the >seats due to weight and balance issues. I'll be running the battery >cables up to the firewall area and need to decide how to deal with the >ground cable. Would it be better to hook it on the cockpit side of the >firewall and attach it to your 24 prong ground plane and then use a >'patch cable' on the engine side of the firewall to the crankcase? The ground block is intended to be used just as you've described. The ideal installation runs (-) lead(s) for battery plus a crankcase ground strap to the single brass bolt through the firewall. All other grounds are best routed to the same block with the exceptions of strobe power supply, landing and taxi lights, pitot heater and nav lights can use local grounds where practical on a metal airframe. >If I understand the grounding and resistance issues properly (as far as >the starter is concerned), it's important to have as little resistance >as possible and having a good ground system is vital to ensure that the >voltage available to the starter is sufficient. Since every attachment >point raises the resistance level I wasn't sure if I should run the >negative side of the battery to the crankcase and then jumper it back to >the 24 prong ground plane or since the airplane is all metal, just run >the ground cable to the crankcase and not worry about the jumper cable. I don't know as it's "vital" . . . just good engineering practice. A couple of hundred thousand airplanes were NOT wired this way and they operate mostly sorta okay . . . but if we know of a better way and it's easy to do, why not? Bob . . . ________________________________ Message 33 ____________________________________ Time: 08:46:29 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Electrical Noise in aircraft wiring --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" >I just happened to be poking around at an Intel Microcontroller >site, and found the following application note AN-125, which >succinctly discusses this topic: > >http://www.intel.com/design/auto/mcs96/applnots/21031302.PDF > >"Designing Microcontroller Systems for Electrically Noisy >Environments". > >Read the app note. Study it. There will be a quiz.... This is an excellent piece that describes the practical use of a lot of good physics . . . but while many of the principals are common, the applications are not well translated from microprocessor-based-black- box into a how-to-wire-airplanes language. Most noise problems in airplanes come from poor ground architectures. Single point grounding takes care of this. This leaves use with a very few issues that involve radiated or electro-statically coupled noise which are generally pretty easy to predict and avoid in the design phase and easy to fix if discover that we've stubbed our toe at some later time. I don't think I'd recommend the airframe guy spend much time with this piece. But if you've a hanker'n to craft some sort of new black box, it's probably required reading whether your box is processor based or not. Bob . . . ________________________________ Message 34 ____________________________________ Time: 08:49:24 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Too close to my compass? --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:07 PM 3/20/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Sam Hoskins" > > >I am retrofitting my fiberglass aircraft with a B&C 200G alternator and >accompanying regulator & filter capacitor. Space behind the panel is at a >premium, and it is very difficult to work down there, close to the firewall. > >I would like to install the voltage regulator right behind the panel, but >this location is about 6" forward of my whiskey compass. Do you think this >will present a problem and create magnetic interference? probably >If I had my druthers, I would really like to mount it on the forward side of >the firewall, but the installation diagram calls for the aft side of the FW. it will be okay on the forward side. You need to keep all wiring as far as possible from compass. Bob . . . ________________________________ Message 35 ____________________________________ Time: 09:28:53 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Firewall penetraton for wires --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 08:30 PM 3/20/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Ron Triano" > >Hi Bob, Just started reading your book, Is (fire Sleave) something I >have not got to yet? Not familiar with it. > >Ron Triano See http://www.paragonperformance.com/Fire%20Sleeve.html http://www.amstreetrod.com/html/firesleeve.html#desc http://www.chiefaircraft.com/Aircraft/HoseFittings/AeroquipFiresleeve.html Used lots of places under cowl . . . protecting firewall penetrations for wires is but one application. See http://www.aeroelectric.com/articles/Firewall_Penetration/firewall.html Bob . . .