---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 03/29/03: 19 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:40 AM - Alternator Systems (Mike Lehman) 2. 07:31 AM - headphone sockets (Fergus Kyle) 3. 07:47 AM - Re: Placing headset jacks (Paul Messinger) 4. 08:05 AM - Resetting C/Bs (Fergus Kyle) 5. 08:16 AM - Re: Alternator Systems (Paul Messinger) 6. 09:32 AM - Resetting C/Bs (David Swartzendruber) 7. 10:44 AM - Firewall penetration (David Carter) 8. 11:10 AM - Re: Alternator Systems (Robert L. Nuckolls, III) 9. 11:19 AM - Re: Resetting C/Bs (Paul Messinger) 10. 02:01 PM - Re: Resetting C/Bs (Robert L. Nuckolls, III) 11. 02:07 PM - Re: Resetting C/Bs (Robert L. Nuckolls, III) 12. 03:19 PM - Radio Noise (cecilth@juno.com) 13. 03:19 PM - Re: Resetting C/Bs (David Swartzendruber) 14. 03:28 PM - Re: Resetting C/Bs (Tom FRIEDLAND) 15. 03:58 PM - Re: Firewall penetration (Ron) 16. 04:11 PM - Re: Alternator Systems (Benford2@aol.com) 17. 05:45 PM - Re: Firewall penetration (Julia) 18. 05:59 PM - Re: Firewall penetration (Julia) 19. 10:55 PM - question on alternators/controllers (Aucountry@aol.com) ________________________________ Message 1 _____________________________________ Time: 06:40:52 AM PST US From: "Mike Lehman" Subject: AeroElectric-List: Alternator Systems --> AeroElectric-List message posted by: "Mike Lehman" Paul Messinger, I've just received a delivery fail notice for this reply (edited) sent to you privately (because the idea was posted previously) about 5 days ago:- Paul, I'd like to extend your analysis 1 step. We've got an external voltage regulator powered via a 5 amp field supply breaker. However, virtually all light aircraft then power the field breaker from the battery side of the 'B' lead fuse/breaker (typically 40 to 60 amps rating). If this main breaker/fuse opens, the VR senses low voltage and maximizes alternator field current in the impossible attempt to restore 13.8 to 14.5 volts on the disconnected buss. The result is 100+ volts at the alternator B terminal and sometimes severe alternator damage involving the faults mentioned. In my opinion, the field supply breaker should be powered from the alternator side of the main breaker. Regards, Mike ________________________________ Message 2 _____________________________________ Time: 07:31:31 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: headphone sockets --> AeroElectric-List message posted by: "Fergus Kyle" ">Hello Mark, After 44 years plus of plugging headsets plugs into a wide >variety of locations I came to the conclusion that the best location for the >pilot's headset jacks (in a side by side seating arrangement) was behind the >copilots seat back and the best location for the copilots headset jacks was >behind the pilots seatback. In sight and always reachable even when strapped >in. No plugs to bump with your knee and no cords lying across your lap. Agreed. I was going to suggest above, behind and outboard of the seat. I put some intercom systems in C-150s and moved the mic-headset jacks to small boxes behind the seats. Cords were always out of the way. Bob . . . " Cheers, On the topic of 'where do I put the headphone holes?', I thought back to the fighter cockpits of yore (where space CAN be a problem, and hard treatment also) in considering where mine ought to go. In one, the plugs entered a socket pair on the wall at the right knee. One leaned forward on entry and plugged in - the lines draped down to the ankle and either inside or outside the belts. Damage to the leads was minimal but was result of unsnagging on occasion. In another, the sets were plugged in behind the head (plug in the helmet, set it aside, then enter ). This produced a twofoot loop to permit reaching forward, but was innocuous enough except for the entry need. The third was the simplest - it plugged in at the hip on the bump seat. Easy to attach, easy to avoid (came up the back of one shoulder), minimum loop because the required length stayed constant, and if you gotta go, the headset required no unplugging. This site is mitigated somewhat by having to be protected against dust etc. The number of aviators is legion, whose necks were stretched by helmets plugged into departed aircraft. Might be worth considering - Ferg Europa A064 ________________________________ Message 3 _____________________________________ Time: 07:47:06 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Placing headset jacks --> AeroElectric-List message posted by: "Paul Messinger" I would put them so the cords are on the inside between the pilots but otherwise agree with you both. My logic is if you need to exit in a rush there are no cords between you and the door. Paul ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Placing headset jacks > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 12:15 PM 3/28/2003 -0500, you wrote: > >--> AeroElectric-List message posted by: BAKEROCB@aol.com > > > >AeroElectric-List message posted by: Mark Phillips on > >placing headset jacks > > > ><<.....skip....Now if I could just decide where to drill these six little > >holes! > > ....skip...... Mark Phillips >> > > > >3/28/2003 > > > >Hello Mark, After 44 years plus of plugging headsets plugs into a wide > >variety of locations I came to the conclusion that the best location for the > >pilot's headset jacks (in a side by side seating arrangement) was behind the > >copilots seat back and the best location for the copilots headset jacks was > >behind the pilots seatback. In sight and always reachable even when strapped > >in. No plugs to bump with your knee and no cords lying across your lap. > > Agreed. I was going to suggest above, behind and outboard of the > seat. I put some intercom systems in C-150s and moved the > mic-headset jacks to small boxes behind the seats. Cords were > always out of the way. > > Bob . . . > > ________________________________ Message 4 _____________________________________ Time: 08:05:00 AM PST US From: "Fergus Kyle" Subject: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "Fergus Kyle" "Bob is clearly right on with this one. Ricky Nelson and several others were KILLED by a flight crew person repeatedly resetting a circuit breaker on a DC3 till the heater went up in smoke. !!!!!!!" Cheers, See also: Air Canada DC-9 fire at Pittsburgh - and it doesn't take aircrew to screw up - too many C/Bs in the cabin make that possible. Wonder where the C/B for cabin entertainment on Swissair's FLt 111 was? ....and, bibliography on Kapton wiring may also provide info! Ferg ________________________________ Message 5 _____________________________________ Time: 08:16:28 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Alternator Systems --> AeroElectric-List message posted by: "Paul Messinger" Thanks, Some of us who live in the outskirts have problems from time to time with the local ISP. Also lost mail etc. Not to mention no reasonable cost hispeed access. Fast here is 26K. While this should not be a design used by experimentals ( or any one ) I agree with your point. Thanks for the extra effort to contact me. Paul ----- Original Message ----- From: "Mike Lehman" Subject: AeroElectric-List: Alternator Systems > --> AeroElectric-List message posted by: "Mike Lehman" > > Paul Messinger, > > I've just received a delivery fail notice for this reply (edited) sent to you privately (because the idea was posted previously) about 5 days ago:- > > Paul, > > I'd like to extend your analysis 1 step. > > We've got an external voltage regulator powered via a 5 amp field supply breaker. However, virtually all light aircraft then power the field breaker from the battery side of the 'B' lead fuse/breaker (typically 40 to 60 amps rating). If this main breaker/fuse opens, the VR senses low voltage and maximizes alternator field current in the impossible attempt to restore 13.8 to 14.5 volts on the disconnected buss. The result is 100+ volts at the alternator B terminal and sometimes severe alternator damage involving the faults mentioned. In my opinion, the field supply breaker should be powered from the alternator side of the main breaker. > > Regards, > Mike > > ________________________________ Message 6 _____________________________________ Time: 09:32:29 AM PST US From: "David Swartzendruber" Subject: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "David Swartzendruber" I'm involved in a discussion concerning resettable circuit protection verses non-resettable in certified aircraft. Any resources you guys can recommend would be appreciated. One of the challenges with the non-resettable argument for certified aircraft is that after certification, an aircraft is hard to change. If it gets through certification with a system that has nuisance tripping of the circuit protection device, the owner is stuck with it. Therefore you have the argument that you need to be able to reset the circuit breaker because you can't fix the problem. The other argument I'm facing is that even though there may be a plan B when plan A fails, plan A is more convenient. Therefore, if we can use plan A even a few more times by simply resetting the circuit breaker, it's better for the pilot. What I would like to determine is whether there is enough of a safety hazard to resetting circuit breakers to offset the need to reset a poorly designed system that can't be changed. Dave in Wichita ________________________________ Message 7 _____________________________________ Time: 10:44:49 AM PST US From: "David Carter" Subject: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: "David Carter" For Ron Triano, ref your e-mail to the list Sat March 1st, I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending on length, 1 1/4" dia I think, with welded flange. I'd rather have the 5/8 diameter that you are using. Can you tell us where you bought it (or where we could buy it), manufacturer, part number? I can't find any "towel racks" that have this stainless steel flange on hollow tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar. David Carter ________________________________ Message 8 _____________________________________ Time: 11:10:39 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Alternator Systems --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:34 AM 3/29/2003 -0500, you wrote: >--> AeroElectric-List message posted by: "Mike Lehman" > > >Paul Messinger, > >I've just received a delivery fail notice for this reply (edited) sent to >you privately (because the idea was posted previously) about 5 days ago:- > >Paul, > >I'd like to extend your analysis 1 step. > >We've got an external voltage regulator powered via a 5 amp field supply >breaker. However, virtually all light aircraft then power the field >breaker from the battery side of the 'B' lead fuse/breaker (typically 40 >to 60 amps rating). If this main breaker/fuse opens, the VR senses low >voltage and maximizes alternator field current in the impossible attempt >to restore 13.8 to 14.5 volts on the disconnected buss. The result is >100+ volts at the alternator B terminal and sometimes severe alternator >damage involving the faults mentioned. In my opinion, the field supply >breaker should be powered from the alternator side of the main breaker. I have seen this theory advanced before . . . and illustrated in a number of wiring diagrams . . . some on STC'd alternator installations for certified aircraft. Consider that the 60A breaker on virtually ALL production aircraft with alternators is DESIGNED to nuisance trip. I've had it happen to me on one occasion. In this instance and many others observed over the years, the regulator does indeed go to full-output in an attempt to raise bus voltage. I've never talked to the designers who choose to wire the field supply to the alternator side of the b-lead breaker . . . so I can only guess at their rational for doing so. It's fairly easy to deduce the effects of this architecture under various abnormal conditions. If the b-lead breaker is open before the system is brought up, the alternator never gets start-up power from the bus and as long as the alternator is incapable of self exciting, it will remain dormant after engine start irrespective of switch positions. If the b-lead breaker opens due to nuisance trip after the system is running, then the alternator is indeed isolated from the bus and it may continue to run self excited but regulated. I cannot deduce any particular benefit for wiring the system this way. It may be that the designer was concerned about the potential for diode failure in the "runaway" condition that results when the regulator looses sight of the b-lead output voltage. Diode failure under open-circuit runaway conditions was a key component of Paul's failure mode hypothesis that I didn't recognize at first. Let's examine this hypothesis: I've heard also that typical alternator diodes are RATED at 200 piv or thereabouts. In some components, it may be rational to assume that the device is at high risk of failure at 225 or even 250 volts. Considering the fact that b-lead breakers open routinely in certified ships and often goes unnoticed for minutes to hours suggests that the non-regenerative runaway (field stays at bus voltage) doesn't produce a lot of failures. I've read many dark-n-stormy night stories and even my own experience has demonstrated that this is not an automatic recipe for diode failure. About 40 years ago, I was doing design work in a nuclear fuel processing plant. I had a task to look at ways to modernize some of our GM tube radiation detectors. The GM tube needed a relatively constant 900 volt source for proper operation. At the suggestion of one of the best teachers I ever had, I explored the avalanche (breakdown) voltage of garden variety silicon diodes. I found that many 400 volt rated devices went into avalanche in the 900 +/- 50V range I was looking for. The current we subjected these devices to was on the order of 10-20 MICROamps so the energy dissipated was well within the physical ability of the diode to tolerate. Here's an example of how a diode could be usefully operated in a mode that might otherwise prove fatal to the device. The interesting point of this experience was that the 400 volt devices didn't go into potentially fatal avalanche operation at voltages more than TWICE the rated voltage of the device. Of course, this is quite temperature dependent and in no way suggests that we should count on a run-of-the-mill alternator diode being good for 400 volts . . . my point is that past experience shows that these alternators are routinely capable of sustained operation at 8-15 times normal output voltage without suffering diode failure. Which brings me to the condition Paul was considering hazardous. I agree that diode failure (opens or shorts) and/or mechanical shorts in windings to the core are necessary to produce burned windings. In a 3-phase alternator, each winding carries an average of 1/3 total output meaning that a 60A alternator can be wound with 20A wire. When load sharing is upset by any of several failures, stator windings are indeed at risk of overload and destruction. Never-the-less, destruction of the windings while smelly is not very spectacular and given their location on the engine, they represent no risk of bringing one spiraling out of the sky trailing black smoke and flames. Getting back to the idea of relocating the field feed breaker to the alternator side of the b-lead breaker . . . The only benefit I can deduce for this design is to limit the alternator's output in case the b-lead breaker nuisance trips. We KNOW this to be a long standing, well understood problem with the design of most certified ships flying . . . it seems better to up-size the b-lead protection to ELIMINATE the nuisance trip than to relocate field feed point to ACCOMMODATE what amounts to a basic design flaw. One last failure mode: In the case of REGENERATIVE runaway for an alternator with a built-in regulator where we deliberately cut the b-lead loose from the airplane, there is certainly an increased risk of loosing diodes compared to the simple fixed-field runaway that occurs when the b-lead breaker opens and the field stays at 12v. This is a toss of the coin. We know that b-lead output will rise quickly to levels that are greater than fix-field levels. It seems like the alternator design would benefit from an internal field fuse rated at, say 5A. This is much higher than any normal field currents but much lower than what would be induced by a regenerative runaway . . . the I(squared)*T constant for the fuse is much shorter than for 22AWG field winding wire. A regenerative runaway event would terminate very quickly at much less risk to the diodes. The likelihood of ever having an ov condition is low. Likelihood of burning stator wires is not zero but it's low. Likelihood of a burned wire being a hazard is extremely low. Aside from having rotors balanced (with pulley installed), I can think of nothing we might do to INCREASE reliability of these inexpensive and robust products. I find no compelling reason to discourage anyone from taking advantage of modern, internally regulated alternators when fitted with a means for containing an overvoltage event. These alternators are demonstrably better products than those flying most certified ships today. Many OBAM aircraft owners have elected to run one-wire alternators without ov protection. The odds of a trouble free operation over the lifetime of the airplane are very much in their favor. Bob . . . ________________________________ Message 9 _____________________________________ Time: 11:19:35 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "Paul Messinger" I have had smoke in the cockpit in certificated acft a couple of times. A master breaker saved my butt once as it was in IFR. Turned out to be COM #2. breaker never opened as short was current limited and hist burned internal to radio. The other case was the same but could have continued with master off if needed. Had I not has a manually openable CB I am not sure how things would have turned out. So its not just a CB but if you have one be sure you can pull it open. What I did was to pull the master and then each individual CB. reset master and close others one at a time until source of smoke was found. No radio/nav was not really an option in IFR. However all the cases of crashes etc from having resetable CB is from the pilots or crews lack of the first rule of flight. FLY THE AIRPLANE FIRST AND ALWAYS. Many pilots allow a problem to distract them and the result is usually very bad. A simple problem crashed the afft because of pilot distraction. Thus I feel in most cases Bob is right. Design your acft so you can keep going with no inflight trouble shooting needed. Paul ----- Original Message ----- From: "David Swartzendruber" Subject: AeroElectric-List: Resetting C/Bs > --> AeroElectric-List message posted by: "David Swartzendruber" > > I'm involved in a discussion concerning resettable circuit protection verses > non-resettable in certified aircraft. Any resources you guys can recommend > would be appreciated. > > One of the challenges with the non-resettable argument for certified > aircraft is that after certification, an aircraft is hard to change. If it > gets through certification with a system that has nuisance tripping of the > circuit protection device, the owner is stuck with it. Therefore you have > the argument that you need to be able to reset the circuit breaker because > you can't fix the problem. > > The other argument I'm facing is that even though there may be a plan B when > plan A fails, plan A is more convenient. Therefore, if we can use plan A > even a few more times by simply resetting the circuit breaker, it's better > for the pilot. > > What I would like to determine is whether there is enough of a safety hazard > to resetting circuit breakers to offset the need to reset a poorly designed > system that can't be changed. > > Dave in Wichita > > ________________________________ Message 10 ____________________________________ Time: 02:01:31 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:37 AM 3/29/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "David Swartzendruber" > > >I'm involved in a discussion concerning resettable circuit protection verses >non-resettable in certified aircraft. Any resources you guys can recommend >would be appreciated. > >One of the challenges with the non-resettable argument for certified >aircraft is that after certification, an aircraft is hard to change. If it >gets through certification with a system that has nuisance tripping of the >circuit protection device, the owner is stuck with it. Therefore you have >the argument that you need to be able to reset the circuit breaker because >you can't fix the problem. > >The other argument I'm facing is that even though there may be a plan B when >plan A fails, plan A is more convenient. Therefore, if we can use plan A >even a few more times by simply resetting the circuit breaker, it's better >for the pilot. > >What I would like to determine is whether there is enough of a safety hazard >to resetting circuit breakers to offset the need to reset a poorly designed >system that can't be changed. Why would a poorly designed system have to go to production? Surely we've got plenty of lessons learned from the past 5 decades of aircraft production. It's hard to beat good critical design review from a cadre of folks who understand the goals AND the history of where we've come from. In the final analysis, when in doubt, make it the next size bigger. There's nothing that prohibits you from piping power to a product on bigger wires than might otherwise be assumed adequate. Knowing the characteristics of the load is useful too . . . "Oh yeah, when it goes into the self cleaning mode, current draw is 50% above operating mode . . . we recommend you don't punch that button while airborne . . ." The questions that bite later are the ones not asked going in. No matter how convenient Plan A, there will always be a whole lot more failure modes that DON'T pop the breaker than the ones which DO pop the breaker. Likelihood of "saving the day" or even improving levels of comfort for having a breaker to punch is very low. Bob . . . ________________________________ Message 11 ____________________________________ Time: 02:07:41 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:19 AM 3/29/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > > >I have had smoke in the cockpit in certificated acft a couple of times. A >master breaker saved my butt once as it was in IFR. what's a "master breaker"? > Turned out to be COM #2. >breaker never opened as short was current limited and hist burned internal >to radio. The other case was the same but could have continued with master >off if needed. >Had I not has a manually openable CB I am not sure how things would have >turned out. So its not just a CB but if you have one be sure you can pull it >open. I'm surprised that the on/off switch for a radio didn't offer a disconnect for everything powered within the radio. >What I did was to pull the master and then each individual CB. reset master >and close others one at a time until source of smoke was found. No radio/nav >was not really an option in IFR. > >However all the cases of crashes etc from having resetable CB is from the >pilots or crews lack of the first rule of flight. FLY THE AIRPLANE FIRST AND >ALWAYS. > >Many pilots allow a problem to distract them and the result is usually very >bad. A simple problem crashed the acft because of pilot distraction. > >Thus I feel in most cases Bob is right. Design your acft so you can keep >going with no inflight trouble shooting needed. I think Dave's issue was whether or not to offer breakers that can be re-closed . . . for example, most production SE Cessnas have push-only breakers. If one can justify putting those breakers out of reach -or- replacing with no-flight-fiddling fuses, are risks to the outcome of flight increased? I would suggest that risks are decreased due to reduced pilot distraction as long as one has a plan-B alternative for the most necessary equipment items. Bob . . . >Paul > > >----- Original Message ----- >From: "David Swartzendruber" >To: >Subject: AeroElectric-List: Resetting C/Bs > > > > --> AeroElectric-List message posted by: "David Swartzendruber" > > > > > I'm involved in a discussion concerning resettable circuit protection >verses > > non-resettable in certified aircraft. Any resources you guys can >recommend > > would be appreciated. > > > > One of the challenges with the non-resettable argument for certified > > aircraft is that after certification, an aircraft is hard to change. If >it > > gets through certification with a system that has nuisance tripping of the > > circuit protection device, the owner is stuck with it. Therefore you have > > the argument that you need to be able to reset the circuit breaker because > > you can't fix the problem. > > > > The other argument I'm facing is that even though there may be a plan B >when > > plan A fails, plan A is more convenient. Therefore, if we can use plan A > > even a few more times by simply resetting the circuit breaker, it's better > > for the pilot. > > > > What I would like to determine is whether there is enough of a safety >hazard > > to resetting circuit breakers to offset the need to reset a poorly >designed > > system that can't be changed. > > > > Dave in Wichita > > > > > > Bob . . . |-------------------------------------------------------| | The man who does not read good books has no advantage | | over the man who cannot read them. | | - Mark Twain | |-------------------------------------------------------| ________________________________ Message 12 ____________________________________ Time: 03:19:31 PM PST US Subject: AeroElectric-List: Radio Noise From: cecilth@juno.com --> AeroElectric-List message posted by: cecilth@juno.com I have shop radio noise. AM Radio I ran shielded cable to a roof antenna thats isolated from all metal. Roof side grounded to ground pipe. Radio side grounded to radio. Have lots of ballasts in ceiling lights. Can't seem to get rid of the noise while I work on my RV6A. Do not archive. Cecil needs help. ________________________________ Message 13 ____________________________________ Time: 03:19:32 PM PST US From: "David Swartzendruber" Subject: Re: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "David Swartzendruber" See comments below: Dave in Wichita > Why would a poorly designed system have to go to production? > Surely we've got plenty of lessons learned from the past 5 decades > of aircraft production. It's hard to beat good critical design review > from a cadre of folks who understand the goals AND the > history of where we've come from. In the final analysis, > when in doubt, make it the next size bigger. There's nothing > that prohibits you from piping power to a product on bigger > wires than might otherwise be assumed adequate. Knowing the > characteristics of the load is useful too . . . "Oh yeah, > when it goes into the self cleaning mode, current draw > is 50% above operating mode . . . we recommend you don't > punch that button while airborne . . ." The questions > that bite later are the ones not asked going in. Perhaps the nuisance tripping situations I'm thinking of shouldn't really be called nuisance tripping. Some of the failure modes I'm thinking of are flap systems that get out of rig and allow the motor to drive to a hard mechanical stop and pop the breaker. Reversing the direction and resetting the breaker gets you back into business where a fuse wouldn't. I was told by a pilot in on the discussion that he is flying a Cheyenne with the same sort of problem with a deicing flap of some sort. The group I'm part of would like to tell the world of certified airframers that we are the answer to their electrical needs. From power generation, to complete distribution. Some customers may not give us much freedom in redesigning the individual systems, so we have to accomodate the quirks of the existing pieces of the system as best we can. One of those quirks may be a failure mode where the system could be recovered if the circuit protection device could be reset. > > No matter how convenient Plan A, there will always > be a whole lot more failure modes that DON'T pop > the breaker than the ones which DO pop the breaker. > Likelihood of "saving the day" or even improving > levels of comfort for having a breaker to punch > is very low. > The response I got to that argument when I made it was that even if we are only able to recover the system 1% of the times we reset the breaker, we need to do it for the 1% of times because the assumption is that there is no downside to the ability of being able to reset. This was with the premise that cost and panel space were not a problem. If there was an additional argument, such as safety, that could be made against resetting, it would go a long way. The other part of the equation is that from a business perspective, it may be easier to win over more potential customers if we offered resettable circuit protection than if we have to go through this same argument and convincing process with each customer. It's very appealing to some to be able to offer a big "WOW" factor with systems involving data busses that control and monitor everything, flat screen control and warning panels that can display information in many colors and allow you to control anything at the touch of a button. How can a fuse and switch be "state of the art"? The Cheyenne pilot I mentioned earlier said that you won't be able to get pilots to give up the ability to do troubleshooting. That's why they go to flight safety training and all that. ________________________________ Message 14 ____________________________________ Time: 03:28:13 PM PST US From: "Tom FRIEDLAND" Subject: RE: AeroElectric-List: Resetting C/Bs --> AeroElectric-List message posted by: "Tom FRIEDLAND" >No radio/nav was not really an option in IFR. Not necessarily... I left DesMoine IFR for Denver when we lost the generator and all battery power. (Army Beaver) We had gyros and a mag compass and flew a direct compass course for 3 hours at our last assigned altitude. We eventually saw Pikes Peak and got light signals to clear to land. ATC had 7000 feet cleared for most of the Midwest! Tom Friedland -----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: Resetting C/Bs --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:19 AM 3/29/2003 -0800, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > > >I have had smoke in the cockpit in certificated acft a couple of times. A >master breaker saved my butt once as it was in IFR. what's a "master breaker"? > Turned out to be COM #2. >breaker never opened as short was current limited and hist burned internal >to radio. The other case was the same but could have continued with master >off if needed. >Had I not has a manually openable CB I am not sure how things would have >turned out. So its not just a CB but if you have one be sure you can pull it >open. I'm surprised that the on/off switch for a radio didn't offer a disconnect for everything powered within the radio. >What I did was to pull the master and then each individual CB. reset master >and close others one at a time until source of smoke was found. No radio/nav >was not really an option in IFR. > >However all the cases of crashes etc from having resetable CB is from the >pilots or crews lack of the first rule of flight. FLY THE AIRPLANE FIRST AND >ALWAYS. > >Many pilots allow a problem to distract them and the result is usually very >bad. A simple problem crashed the acft because of pilot distraction. > >Thus I feel in most cases Bob is right. Design your acft so you can keep >going with no inflight trouble shooting needed. I think Dave's issue was whether or not to offer breakers that can be re-closed . . . for example, most production SE Cessnas have push-only breakers. If one can justify putting those breakers out of reach -or- replacing with no-flight-fiddling fuses, are risks to the outcome of flight increased? I would suggest that risks are decreased due to reduced pilot distraction as long as one has a plan-B alternative for the most necessary equipment items. Bob . . . >Paul > > >----- Original Message ----- >From: "David Swartzendruber" >To: >Subject: AeroElectric-List: Resetting C/Bs > > > > --> AeroElectric-List message posted by: "David Swartzendruber" > > > > > I'm involved in a discussion concerning resettable circuit protection >verses > > non-resettable in certified aircraft. Any resources you guys can >recommend > > would be appreciated. > > > > One of the challenges with the non-resettable argument for certified > > aircraft is that after certification, an aircraft is hard to change. If >it > > gets through certification with a system that has nuisance tripping of the > > circuit protection device, the owner is stuck with it. Therefore you have > > the argument that you need to be able to reset the circuit breaker because > > you can't fix the problem. > > > > The other argument I'm facing is that even though there may be a plan B >when > > plan A fails, plan A is more convenient. Therefore, if we can use plan A > > even a few more times by simply resetting the circuit breaker, it's better > > for the pilot. > > > > What I would like to determine is whether there is enough of a safety >hazard > > to resetting circuit breakers to offset the need to reset a poorly >designed > > system that can't be changed. > > > > Dave in Wichita > > > > > > Bob . . . |-------------------------------------------------------| | The man who does not read good books has no advantage | | over the man who cannot read them. | | - Mark Twain | |-------------------------------------------------------| ________________________________ Message 15 ____________________________________ Time: 03:58:15 PM PST US From: Ron Subject: RE: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: Ron Hi Dave, I did not purchase mine, they were left over from a store I built in the bay area CA, The owner of the store supplied all the hardware. i will see if I can find out where they purchased them, Find a store that sells bobrick hardware. I believe that was the kind. If not it would be pretty easy to weld up some. Ron Triano -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of David Carter Subject: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: "David Carter" For Ron Triano, ref your e-mail to the list Sat March 1st, I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending on length, 1 1/4" dia I think, with welded flange. I'd rather have the 5/8 diameter that you are using. Can you tell us where you bought it (or where we could buy it), manufacturer, part number? I can't find any "towel racks" that have this stainless steel flange on hollow tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar. David Carter ________________________________ Message 16 ____________________________________ Time: 04:11:55 PM PST US From: Benford2@aol.com Subject: Re: AeroElectric-List: Alternator Systems --> AeroElectric-List message posted by: Benford2@aol.com In a message dated 3/29/2003 1:37:19 PM Mountain Standard Time, bob.nuckolls@cox.net writes: > > I find no compelling reason to discourage anyone > from taking advantage of modern, internally > regulated alternators when fitted with a means > for containing an overvoltage event. These > alternators are demonstrably better products > than those flying most certified ships today. > Many OBAM aircraft owners have elected to run > one-wire alternators without ov protection. > The odds of a trouble free operation over the > lifetime of the airplane are very much in their > favor. > > Bob . . . > Once again I want to thank you for all your time you spend explaining the finer details of the electrical systems. Not only are you VERY sharp in the field you are willing to take time to help us all out in understanding the workings of our charging systems. I hope we meet one day at a fly in because you are getting a nice dinner paid for by me. Thanks again. Ben Haas. N801BH. Jackson Hole WY. ________________________________ Message 17 ____________________________________ Time: 05:45:33 PM PST US From: Julia Subject: Re: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: Julia I used the 1 1/4 OD size - ran ALL off my engine wires through AN10 fire sleeve (I think that was the size) and ran the fire sleeve throught the 1 1/4 OD firewall fitting. The fitting I got had 3 mount holes in the flange - I mounted the engine side with the tube pointing down at about a 45degree angle then on the inside I mounted the other half facing straight up - maybe that's overkill but I was able to use only the three holes in each flange. I was able to have ALL my wires run through firesleeve to protect them from chaffing inside the firewall fitting. Then to top it all off on the outside I put a larger firesleeve around the entire bundle which will slide back over the outside of the 1 1/4 tube on the firewall fitting. I'll put a hose clamp on that piece to hold it in place. It came out slick as can be. I highly recommend it. it is loose enough so I might slip a couple more wires through without having to take the fittings off the firewall. by the time you get everything run, it's quite a big bundle of wires -I kept forgetting things -like 4 EGT & 4 CHT probe wires take up some room if you get the ones shielded - and then they already have the ends on them - so that complicates getting it through the tube - having done it- you could never persuade me to go with smaller tube size. The only other wire I ran was my Bat. buss wire - that's supposed to be only 6 inches and I ran it using another rig. my 2 cents for now. David Carter wrote:--> AeroElectric-List message posted by: "David Carter" For Ron Triano, ref your e-mail to the list Sat March 1st, I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending on length, 1 1/4" dia I think, with welded flange. I'd rather have the 5/8 diameter that you are using. Can you tell us where you bought it (or where we could buy it), manufacturer, part number? I can't find any "towel racks" that have this stainless steel flange on hollow tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar. David Carter --------------------------------- ________________________________ Message 18 ____________________________________ Time: 05:59:41 PM PST US From: Julia Subject: RE: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: Julia you want Franklin Brass (a Masco Company), #6424 - grab bar - 24 inch - stainless steel, UPS code 0-79171-64245-6 - I got mine at home depot. once in a while I have a good idea and this one is REALLY good. mines all done and looks totally awesome. Ron wrote:--> AeroElectric-List message posted by: Ron Hi Dave, I did not purchase mine, they were left over from a store I built in the bay area CA, The owner of the store supplied all the hardware. i will see if I can find out where they purchased them, Find a store that sells bobrick hardware. I believe that was the kind. If not it would be pretty easy to weld up some. Ron Triano -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of David Carter Subject: AeroElectric-List: Firewall penetration --> AeroElectric-List message posted by: "David Carter" For Ron Triano, ref your e-mail to the list Sat March 1st, I looked at stainless steel grab bars at Lowe's last night - $18 to $20 depending on length, 1 1/4" dia I think, with welded flange. I'd rather have the 5/8 diameter that you are using. Can you tell us where you bought it (or where we could buy it), manufacturer, part number? I can't find any "towel racks" that have this stainless steel flange on hollow tube feature. I suspect the 5/8 towel bar will be cheaper than the 1 1/4 dia grab bar. David Carter --------------------------------- ________________________________ Message 19 ____________________________________ Time: 10:55:43 PM PST US From: Aucountry@aol.com Subject: AeroElectric-List: question on alternators/controllers --> AeroElectric-List message posted by: Aucountry@aol.com I Just finished the installation of an overhauled alternator (Aeroelectrics) and new Zeftronics alternaor controller in a Piper PA-24-250 Comanche.=A0 =20I replaced all of the the wires firewall forward.=A0 New ground wires.=A0 Dedicated ground wire from the alternator to the alternator controller.=A0 =20 On engine start, the ammeter goes up like expected then decreases as expected.=A0 The voltage readout on a digital ammeter/voltmeter on the avionics side of the bus bar shows 12.6 volts at idle and 13.0 volts at 1500 RPM.=A0 The voltage readout on the JPI 700 at the same time is 13.0 volts at idle and 13.4 volts at 1500 RPM.=A0 At 1500 RPM with ALL of the switches turned on=20is 12.1 volts on the avionics side and 12.4 on the JPI 700.=A0 The ammeter under a full load shows about 0.0 amps plus or MINUS 0.2 amps. Now, had this been the first time this has happened I'd say more trouble shooting is called for.=A0 However.=A0 I installed an overhauled (from AVIALL) alternator and Zeftronics controller on a Tiger about a year ago and his JPI 700 showed a consistant 12.6 to 13.2 volts under most conditions.=A0 I did the usual and cleaned the grounds, replaced the Master Switch, and cleaned all connections.=A0 Still no change.=A0 The owner decided to take the plane and if there were any problems with the battery not staying charged he'd get back to me.=A0 So far, the battery has stayed charged.=A0 Can the voltage be set on the alternator controllers?=A0 Is there something else I should be looking at or for? Gary