---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 12/22/08: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:57 AM - BOM for control cabinet for line #4 (eddieedwards@mindspring.com) 2. 07:52 AM - Re: AEC 9051 Filtered LED Driver Circuit Question (Robert L. Nuckolls, III) 3. 08:59 AM - Philosophy of Design - Endurance Bus (Dale Rogers) 4. 09:20 AM - Re: Re: Dual Lightspeed Ignition modules () 5. 12:08 PM - Re: Philosophy of Design - Endurance Bus (Robert L. Nuckolls, III) 6. 12:18 PM - Re:LED's (EMAproducts@aol.com) 7. 12:59 PM - Re: Fw: Re: Ignition Switch - VAF Thread (Henry Trzeciakowski) 8. 02:05 PM - Re: Re: Dual Lightspeed Ignition modules (Michael Pereira) 9. 02:28 PM - Re: Li-Ion Batteries for aircraft (Robert L. Nuckolls, III) 10. 02:30 PM - Re: Re:LED's (Robert L. Nuckolls, III) 11. 02:59 PM - Re: Re: Dual Lightspeed Ignition modules (Terry Watson) ________________________________ Message 1 _____________________________________ Time: 06:57:50 AM PST US From: "eddieedwards@mindspring.com" Subject: AeroElectric-List: BOM for control cabinet for line #4 Sarah, See attached a BOM for SMC items that Michael Stahl at Chewning and Wilmer requested. This is for a Control Cabinet on Line #4. Please let me know if there are any problems with part numbers or lead times. Thanks and have a great Holiday, Eddie eddieedwards@mindspring.com EarthLink Revolves Around You. ________________________________ Message 2 _____________________________________ Time: 07:52:25 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: AEC 9051 Filtered LED Driver Circuit Question At 11:23 PM 12/21/2008, you wrote: > >This is probably a question for Bob . . . . > > I am in the process of building an LED driver that has 4 of > the 3021-D-E-1000 Buck Pucks on the same board. I am attempting to > parrot the filter design that Bob used for the AEC 9051 to quiet > down the Buck Pucks but I have a couple of questions: > >1. This board will use PWM (100 Hz) from a PIC to control the >intensity of the LEDs attached to it. The Buck Pucks can be >"flashed" at up to 10 kHz by toggling the control pin between 0 and >5V. I have tested this at 100 Hz and they work very well this way >"bare". If I add the the filter network a-la the AEC 9051 to the >LED+ and LED- lines, will it detrimentally affect the ability to >toggle the output of the Buck Puck on and off at 100 Hz? I suspect >that it won't but I'd like a second (more informed) opinion. No problem . . . >2. Each of the 4 Buck Pucks will have to have it's own filter >network on LED+ and LED-. But I would really like to avoid having >to replicate the filters 4 times for the VIN+ and VIN- lines. If I >combined these into a single filter, would I need to change the >inductance and capacitance values of the components? Inductance and >capacitance values aside, it would seem that I would now have to >have an inductor rated for at least 4A to feed the 4 Buck Pucks. Yes . . . > Does that sound right? The problem there is that a 100uH > inductor rated for 4A is physically pretty large and I'm really > trying to keep the size of this thing down. Any other suggested solutions? The values were WAGGED . . . I didn't have access to the DO160 lab at the time to refine the components. All we know now is that the components cited reduced observed interference to acceptable if not imperceptible levels. The filter may be overkill, or even less than suggested by DO160. There were no objective measurements made. I have some other test programs coming up that may give me an opportunity to check the AEC9051's real noise numbers. In the mean time, the values cited offer a good starting point for your own experiments. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 3 _____________________________________ Time: 08:59:31 AM PST US From: Dale Rogers Subject: AeroElectric-List: Philosophy of Design - Endurance Bus Robert L. Nuckolls, III wrote: > ... > I presume you're talking about the alternate feed path > to the e-bus. What is the value in putting a breaker on > the panel for this function as opposed to a switch? Do you > plan to pre-flight check this path? Is there also wire > protection on this path located right at the battery > bus? Bob, There are apparently some elements of the concept that I don't have a good handle on yet. Forgive me if it is already covered in AEC; but that's a big volume and I'm actually jumping a bit ahead in my build, so that I can do some of the ground-work while it's still convenient to do them in an early stage of the fuselage construction. I'm building a glass pusher (COZY) with an "alternative" engine. No mags. To my understanding - so far - the "endurance" bus has only the things on it that I ~must~ have to conclude my flight safely - albeit possibly truncated - in the event that my alternator fails. So, I'm having a problem understanding why one would want to switch access to that bus. To connect to a back-up supply of electrons? I'm planning to connect the bus supporting my bare essentials directly to the battery, then run a switched/fused connection to my "everything else" bus from that. To accomplish that, I'm running a "0" cable from the B+ terminal to my starter solenoid (about 18") and then a pair of #6 welding cables (+ & -) to the front of the airplane, and another #10 wire to the ECU which, at present, is only a few inches from the battery. Am I overlooking something important? Dale R. ________________________________ Message 4 _____________________________________ Time: 09:20:04 AM PST US Subject: RE: AeroElectric-List: RE: Dual Lightspeed Ignition modules From: Ah, good point Bob. I think as long as aircraft and human nature exist, there is no end. One gets the impression that by introducing new technology we somehow lesson our faith in its reliability. I embrace new technology, but I don't want to have to build a triple-redundant system on the chance it may take a bow. The goal of simplicity with reliability should still be enforced. Glenn -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Friday, December 19, 2008 2:41 PM Subject: RE: AeroElectric-List: RE: Dual Lightspeed Ignition modules At 07:01 AM 12/19/2008, you wrote: > > > How do those feared risks occur? > > How do you get a shorted battery bus failure? How does > connection directly to the battery protect against > an overvoltage condition? What matter of "runaway > device" can you imagine that brings the entire system > to its knees? As long as we're in the free-ranging > imagination mode, how about bursting batteries, > open batteries, etc. etc. > >Lets see, a tool across the bus, or direct short from a chafed wire, the >loss of the ground bus on a composite airplane just to name a few. . . . and are these all not manifestations of poor craftsmanship or maintenance? If we're going to add band-aids to any system that go to offsetting sub-standard behavior by someone who has touched the airplane . . . where does it end? >I have a story from a dark and stormy night where the air conditioner >started to break down and started to draw over 150 amps and caused both >Gen's to go off line and pull the volts down to about seven volts. The >CB didn't trip, everything just went almost completely dark before we >got the air conditioner off. Then we were able to restore power. The >problem, if we couldn't shut the Air conditioner off or couldn't figure >out the problem in time (if this airplane had a battery powered ignition >system) the engine would have failed, where simply turning the bus off >would have restored the engine or maybe even had enough voltage at the >battery to keep the engine running. Oh, the airplane referenced was a >certified airplane. . . . and what did you learn from this or any other story that would give you pause for evaluating your own project? Are there things that could or should have been done in the original design processes that would have prevented this incident? Suppose your RV doesn't even HAVE a piece-of-@#$@# air conditioner.What is the value of taking one incident where the designers/fabricators/maintainers/operators stubbed there collective toes and then levying new requirements on ALL airplanes that work-around the SYMPTOMS of that one case? >Bob, I sometime wonder if you fly or are around flying. This isn't a >hypothesis; it's based on real people in real airplanes. The fact is >that electrical systems fail with regularity, some worse then others. >An engine failure on top of that in many cases is a near death >experience. Loosing the engine is not the same as loosing the >transponder. Why do we use vacuum or backup batteries to power >important instrument systems? Don't you think the ignition system >deserves the same respect? My career in aviation began in 1955 when I helped an uncle install an MANUAL direction finder loop in his 170. He could put holes in the airplane but couldn't read a diagram or solder. I was 12 years old. I retired from Hawker-Beechcraft 18 months ago as the subject matter expert leader in electronics/electrical systems. I'm still contracting to that organization and several others who specialize in aviation design and production. I'm an 1000 hour private pilot with about that many additional hours as a test engineer on TC aircraft and 50 times that time as a designer, qualifier and troubleshooter of airborne systems. I'm now 66 years old and still in the business. >It's not! In aviation failures that occur in the field are often not >reported. Airplanes with electrical systems have been around for less >the 100 years and electronic ignitions in aviation much less. We are >all inventing new system designs that are not able to accept total >failure of the total system. Agreed. But just as fuel flow under all anticipated flight conditions was the big stumbling block for many a designer 70 years ago, we have a new challenge that isn't any different. Just as there's no excuse for total failure of fuel flow, there is NO EXCUSE for total failure of an electrical system. Yeah, it has happened which means there's a REASON but there is still no excuse. >Yes, but not everyone has been here for 10 years and most of the >products and concepts haven't been either. Just because it is new doesn't mean that the thought processes and fabrication techniques for airworthiness are any different than what has worked well for decades. Suppose we consider an RV with a piece of @#$@ air conditioner with a failure mode that sucks down the entire system? Of what value is it to tie one or both systems directly to the (+) battery post? Which is better, refine the A/C design or add weight, complexity, cost-of-ownership to offset the possibility that the A/C causes an unhappy day in the cockpit? On a related topic. Lots of folks are trying to figure out ways to integrate lithium-ion batteries into aircraft. It's no mean task. While the energy/weight radio of l-ion is seductive, it's sorta like figuring out a way to burn nitro-glycerine in your engine. Wow! What energy potential! Now, how do you integrate this potential into an existing, highly refined system in a way that does not increase risk? There are people who worry a lot about things they don't understand. There are people who are paid to worry a lot about things they presumably understand and use force of law to modify our behavior such that THEIR worries are mitigated . . . all in the name of 'safety'. http://www.hsegroup.com/hse/text/caffiene.htm http://aeroelectric.com/Pictures/Misc/Cowboy_after_OSHA.jpg My point about your posting was that it tended to reenforce the notion that there was a valid WORRY to be address without adding understanding. An understanding of design for failure-tolerance, craftsmanship, maintenance and operation such that worries go away. There are few suppliers to aviation that have a working knowledge of low-risk, light-weight, failure- tolerant system design. If we attached every worry-wart's product to the battery(+) post . . . it's easy to see where that idea leads! Bob . . . ________________________________ Message 5 _____________________________________ Time: 12:08:22 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Philosophy of Design - Endurance Bus At 10:56 AM 12/22/2008, you wrote: > >Robert L. Nuckolls, III wrote: >>... >> I presume you're talking about the alternate feed path >> to the e-bus. What is the value in putting a breaker on >> the panel for this function as opposed to a switch? Do you >> plan to pre-flight check this path? Is there also wire >> protection on this path located right at the battery >> bus? > >Bob, > > There are apparently some elements of the concept that I >don't have a good handle on yet. Forgive me if it is already >covered in AEC; but that's a big volume and I'm actually >jumping a bit ahead in my build, so that I can do some of the >ground-work while it's still convenient to do them in an >early stage of the fuselage construction. > > I'm building a glass pusher (COZY) with an "alternative" >engine. No mags. > > To my understanding - so far - the "endurance" bus has only >the things on it that I ~must~ have to conclude my flight >safely - albeit possibly truncated - in the event that my >alternator fails. So, I'm having a problem understanding why >one would want to switch access to that bus. To connect to >a back-up supply of electrons? Not necessarily. The original concept for an E-bus was to support devices useful for en-route flight ops for the purpose of (1) bypassing the battery contactor and eliminating its parasitic (no value added) load and (2) powering up goodies useful for confident continued flight until airport of destination is in sight. > I'm planning to connect the bus supporting my bare >essentials directly to the battery, then run a switched/fused >connection to my "everything else" bus from that. To >accomplish that, I'm running a "0" cable from the B+ >terminal to my starter solenoid (about 18") and then a pair >of #6 welding cables (+ & -) to the front of the airplane, and >another #10 wire to the ECU which, at present, is only a few >inches from the battery. > > Am I overlooking something important? Dunno . . . the z-figures architectures are finely sorted for the purpose of minimizing failure modes, keeping transition from plan-a to plan-b. The grand notion was that loss of an alternator should not automatically turn into an emergency with an immediate landing on foreign tarmac. The premise of the e-bus stood on a 3-legged "stool" that says (a) equipment needed for x-hours of en-route flight can be exceedingly low energy, (b) it's easy to KNOW how long the ship's battery will support this energy requirement and (c) once you're cleared to land, the concrete ahead belongs to you and turning the master switch back ON to support more goodies adds no potential for hazard to the flight even if the battery folds before you get the wheels on the ground. Adding the SD-8 allows one to increase endurance loads up to and perhaps a bit over the ability of the SD-8 to deliver . . . while keeping the battery mostly (if not totally) reserved for descent and approach to landing. If shuffling the busses and re-sorting items feed by those accommodates alternative design goals, by all means. Just be aware not all changes are "golden" and may introduce failure mode effects that demand a new understanding on the part of the pilot. Bob . . . ________________________________ Message 6 _____________________________________ Time: 12:18:12 PM PST US From: EMAproducts@aol.com Subject: AeroElectric-List: Re:LED's Gentlemen: I am not an electronics man, however I have been using LED's in our AOA systems for 14 years. Use caution and be aware just because the LED's come from the same supplier, they may NOT have the same intensity. They also have different dimming requirements for different colors. We have found that if using the Ultra-Bright LED's they must be individually paired (same colors and different) to insure they all dim the same. Not a big deal, but if you are looking for professional results best to take the extra time and compare them prior to soldering and saying darn I should have All except the Ultra bright by the same mfg. seem pretty good, but a large variance even in same order of 50 LED's ordered at same time. Elbie Mendenhall _www.riteangle.com_ (http://www.riteangle.com) **************One site keeps you connected to all your email: AOL Mail, Gmail, and Yahoo Mail. Try it now. ________________________________ Message 7 _____________________________________ Time: 12:59:04 PM PST US From: "Henry Trzeciakowski" Subject: Re: Fw: AeroElectric-List: Re: Ignition Switch - VAF Thread Thanks Bob: ----- Original Message ----- From: Robert L. Nuckolls, III To: aeroelectric-list@matronics.com Sent: Sunday, December 21, 2008 6:48 PM Subject: Re: Fw: AeroElectric-List: Re: Ignition Switch - VAF Thread At 08:08 PM 12/21/2008, you wrote: Thanks Bill: This definitely answers my question.......I can now see the "light" regarding grounding the sheilded wire at both ends per Bob's Z-26......the link to the 2005 VAF Forum was excellent. The one thng I noticed was that they are using 18awg shieded and Bob's Z-26 uses 20 awg shielded....20 is what I have and plan on using unless 18 is better than 20 !! Thanks again Some TC aircraft designs specify 20AWG or larger to any accessories on the engine . . . it's some sort of robustness thing. I suppose 18AWG is more robust still. On canard pushers, there IS a voltage drop issue for the long run from start switch to the tail mounted starter contactor combined with low battery and cold temperatures. 20AWG is fine but if you have some scraps of 18 laying around waiting for useful duty on your airplane it would be fine too. The only wires that benefit from shielding are the p-leads and then only if wired as depicted in the z-figures. There again 20 is adequate but 18 is fine if you have it. Bob . . . ________________________________ Message 8 _____________________________________ Time: 02:05:32 PM PST US From: "Michael Pereira" Subject: Re: AeroElectric-List: RE: Dual Lightspeed Ignition modules > On a related topic. Lots of folks are trying to figure > out ways to integrate lithium-ion batteries into > aircraft. It's no mean task. While the energy/weight > radio of l-ion is seductive, it's sorta like figuring > out a way to burn nitro-glycerine in your engine. Wow! > What energy potential! Now, how do you integrate > this potential into an existing, highly refined system > in a way that does not increase risk? Oh good lord, li-poly batteries are awesome for *model* aviation. I hope the manufacturers you're alluding to are considering the "A123 Systems" type chemistry batteries (which will take abuse without emiting a napalm like lithium/cobalt fog). ________________________________ Message 9 _____________________________________ Time: 02:28:37 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Li-Ion Batteries for aircraft At 03:59 PM 12/22/2008, you wrote: > > > > On a related topic. Lots of folks are trying to figure > > out ways to integrate lithium-ion batteries into > > aircraft. It's no mean task. While the energy/weight > > radio of l-ion is seductive, it's sorta like figuring > > out a way to burn nitro-glycerine in your engine. Wow! > > What energy potential! Now, how do you integrate > > this potential into an existing, highly refined system > > in a way that does not increase risk? > >Oh good lord, li-poly batteries are awesome for *model* >aviation. I hope the manufacturers you're alluding to are >considering the "A123 Systems" type chemistry batteries (which >will take abuse without emiting a napalm like lithium/cobalt >fog). Everybody with a product has a dog in this hunt. I'm aware of at least three serious efforts by folks who understand batteries and their role in aviation . . . and perhaps a dozen more wannabes. A friend of mine made this anecdotal observation about batteries in the numerous crashes he investigated: He said that if the airplane didn't burn after impact, more often than not, the battery was pitched out and could be found in the weeds. If the airplane did burn, more often than not, the battery was still in the airplane. While an exceedingly unscientific observation, it plays homage to the high energy density of these devices along with their willingness to dump that energy to the outside world without regard to the fondest desires of those individuals close by. Li-Ion batteries have the potential for being several times worse than their lead-acid or ni-cad cousins when it comes to undesirable energy spills! Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 10 ____________________________________ Time: 02:30:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re:LED's At 02:16 PM 12/22/2008, you wrote: > > >Gentlemen: > I am not an electronics man, however I have been using LED's in > our AOA systems for 14 years. Use caution and be aware just > because the LED's come from the same supplier, they may NOT have > the same intensity. They also have different dimming requirements > for different colors. We have found that if using the Ultra-Bright > LED's they must be individually paired (same colors and different) > to insure they all dim the same. Not a big deal, but if you are > looking for professional results best to take the extra time and > compare them prior to soldering and saying darn I should have All > except the Ultra bright by the same mfg. seem pretty good, but a > large variance even in same order of 50 LED's ordered at same time. >Elbie Mendenhall I've heard this before. A number of folks who supply sunlight viewable dead-front annunciators have mentioned a need for matching sets of leds for output to achieve uniform appearance across the panel. Bob . . . ________________________________ Message 11 ____________________________________ Time: 02:59:24 PM PST US From: "Terry Watson" Subject: RE: AeroElectric-List: RE: Dual Lightspeed Ignition modules Here is something from the archives. I think it followed a poll where Bill Dube was asking how many of us would be interested in a really good aircraft battery at a relatively high price: Sep 07, 2007 From: Bill Dube Subject: Re: A123 Systems Nano-phosphate technology and aircraft (was: KillaCycle on Dish Net Tonight) Whomever is designing the electronics doesn't have real experience with A123 Systems cells. They think they are dealing with conventional Li-Ion cells, and they are wrong. A123 Systems nano-phosphate cells are quite different than other Li-Ion cells. They will take a LOT of abuse. About the same amount as an AGM. It is straightforward to make a drop-in replacement for a 12 volt (or 24 volt) lead-acid battery using A123 Systems cells. The existing charging system will work just fine. (It must have the voltage set somewhere between 13.5 and 14.8 volts.) In an airplane, you would want a warning that alerted the pilot that the system was going over 14.8 volts and would make noise if the system was going over 15 volts. It would also be useful to know if the battery temperature was going over 80 Celsius. (You can go up to about 100 C without damage, but no higher or you risk venting the cells and damaging the plastic separator.) >>> Case study <<<< I have had a 3.5 lb A123 Systems battery running in my completely unmodified GMC van for the past 7 months. It snaps the engine over much better than the original 35 lb lead-acid battery. Let's talk about abuse. My wife left my van door unlocked and someone rifled my glove box and left it open with the light on. This killed the battery and it sat at ZERO VOLTS for over a week. I thought, "So much for THAT battery." I then decided to do what the typical consumer would do and I connected up the 3.5 lb completely dead battery to a fully-charged car battery with jumper cables. Hundreds of amps flowed and slightly warmed the cables. I waited a couple of minutes for the 3.5 lb battery voltage to come up, disconnected the jumper cables (the worst thing you could do) and cranked up the van. It started instantly. The alternator then gave the 3.5 lb battery ~100 amps until it came up to 13.4 volts and then tapered off. The BMS showed that all the cells were still in balance! This was five months ago. I haven't capacity-tested the battery, but I can't tell the difference in cranking performance. It was just as if nothing had happened. I even left it parked for 5 weeks while I was out of town and it cranked right up without a problem. If you were to torture a conventional Li-Ion battery like this, it would have burst into flames, or at least it would have just burst. I tell this story to folks with years of experience with conventional Li-Ion cells and they cringe when I get to the part about the jumper cables. :-) The A123 Systems cells will, indeed, "take the abuse". I have a very simplistic charge-balancing electronics (BMS) on my GMC van battery. Nothing fancy is needed. If you overcharge them grossly, they will vent a small amount of flammable vapor (like paint thinner.) If there is an ignition source, this vapor could catch fire. The cells can also burst if overcharged severely. That is the extent of the hazard this technology presents. Bill Dube' -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Michael Pereira Sent: Monday, December 22, 2008 1:59 PM Subject: Re: AeroElectric-List: RE: Dual Lightspeed Ignition modules > On a related topic. Lots of folks are trying to figure > out ways to integrate lithium-ion batteries into > aircraft. It's no mean task. While the energy/weight > radio of l-ion is seductive, it's sorta like figuring > out a way to burn nitro-glycerine in your engine. Wow! > What energy potential! Now, how do you integrate > this potential into an existing, highly refined system > in a way that does not increase risk? Oh good lord, li-poly batteries are awesome for *model* aviation. I hope the manufacturers you're alluding to are considering the "A123 Systems" type chemistry batteries (which will take abuse without emiting a napalm like lithium/cobalt fog). ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.