---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 06/20/04: 22 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:49 AM - Battery data and etc (Paul Messinger) 2. 07:49 AM - Re: New FAA requirement???? (Paul Messinger) 3. 08:15 AM - Re: New FAA requirement???? (BobsV35B@aol.com) 4. 08:18 AM - Battery life (Paul Messinger) 5. 08:30 AM - Phillips Head Screws () 6. 08:33 AM - engine hot starting (Paul Messinger) 7. 08:48 AM - Re: New FAA requirement???? (Dan Morrow) 8. 09:04 AM - Re: New FAA requirement???? (George Braly) 9. 09:07 AM - Re: New FAA requirement???? (Paul Messinger) 10. 09:19 AM - Re: New FAA requirement???? (Dan Morrow) 11. 09:56 AM - Re: New FAA requirement???? (BobsV35B@aol.com) 12. 11:30 AM - Characterization of Westach 720-4a sensor (irampil@notes.cc.sunysb.edu) 13. 11:40 AM - Re: Battery data and etc (Brian Lloyd) 14. 12:18 PM - Re: New FAA requirement???? (Brian Lloyd) 15. 01:03 PM - Re: engine hot starting (Brian Lloyd) 16. 01:05 PM - Re: New FAA requirement???? (Brian Lloyd) 17. 01:14 PM - Re: Characterization of Westach 720-4a sensor (Brian Lloyd) 18. 05:23 PM - Re: engine hot starting (George Braly) 19. 08:55 PM - Re: engine hot starting (Brian Lloyd) 20. 09:56 PM - Alternator Failure (David Chalmers) 21. 10:23 PM - 3 stage voltage regulator (Christopher J Fortin) 22. 11:52 PM - Re: Characterization of Westach 720-4a sensor (James Foerster) ________________________________ Message 1 _____________________________________ Time: 07:49:06 AM PST US From: "Paul Messinger" Subject: AeroElectric-List: Battery data and etc --> AeroElectric-List message posted by: "Paul Messinger" Brian It seems that you do not read my comments and or ignore them. You have personally attacked me in several posts. I finally have gotten tired of this. I have never attacked you personally. Disagreeing with a comment is not a personal attack (its not an attack just a differernt take on the comment not the commenter), or most do not take it that was as you seem to do. I have asked repeatedly for specific info and gotten either no response or ridicule. (I will repeat some of my questions on a different post) Here are a few examples. EXAMPLE#1 "">> I suggest you look at The ODYSSEY battery. Its very different in many >> respects. >I have looked at it and, actually, it's not that different. It is an AGM battery >using the spiral-wound construction technique. This type of battery was >designed for UPS applications and has very low internal resistance right down >to final discharge allowing UPS's to use much smaller and lighter batteries than >they might otherwise need. The UPS designers don't expect them to get used >much so they accept a design that represents a high level of abuse to the >battery."" Well your reply relates to the Optima not the Odyssey (regarding construction)and further the latter part of your comment is not at all consistent with what both manufacturers say about their battery. In fact UPS is not either of the two main points about their design that advertise. So you never bothered to READ and respond to what said or you would not have confused the two manufacturers, And your reply indicated you read neither mfgrs info for where they both say the intended use of the battery is. EXAMPLE #2 >> First; If I ever have a significant depth of discharge, its because of a >> Failure of the electrical system. I would not fly again until I have >> determined the reason for the failure and corrected it including redesign or >> use of different parts. >Wrong. These problems affect battery life even when you are not discharging >the battery. What is WRONG with my statement and what does battery life have to do with it?? EXAMPLE #3 >> important if you want to avoid overcharging the battery. But how much and >> for how long is the issue I am trying to get to. How does the smart charger >> / regulator know how much current is going where given the assumed design >>of >> only a load meter and no battery current sensor per Bob's designs of late. > ... >> I simply do not see how the smart charger/regulator or what ever can tell >> about the battery state of charge without looking at the battery in a stand >> alone mode or at least measuring the input current to the battery. You say >> only the battery temp is needed. >Temp input is needed to set the proper charging voltage. Well IF you look at most any battery mfgrs data they will tell you the ONLY way to tell when to finish and go to the "float" mode is when the battery current reaches a specific current (depending on the battery). Using battery voltage under charge is at best a guess. Paul Perhaps one or more of the following fits :-) " I suffer fools badly" "Its hard to have a battle of wits with an unarmed man" ________________________________ Message 2 _____________________________________ Time: 07:49:06 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: "Paul Messinger" ""One needs to do capacity testing of the battery every 6 months or a year. The FAA is now requiring that at annual for certified aircraft."" We all need to know about your above comment. I have asked both the local FBO and a couple of IA's and no one has ever heard of such a requirement and also say they do not have the equipment to do any capacity testing. PLEASE provide a FAA link to this new requirement. Paul ----- Original Message ----- From: "Brian Lloyd" ________________________________ Message 3 _____________________________________ Time: 08:15:36 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: BobsV35B@aol.com In a message dated 6/20/04 9:49:44 AM Central Daylight Time, paulm@olypen.com writes: --> AeroElectric-List message posted by: "Paul Messinger" ""One needs to do capacity testing of the battery every 6 months or a year. The FAA is now requiring that at annual for certified aircraft."" We all need to know about your above comment. I have asked both the local FBO and a couple of IA's and no one has ever heard of such a requirement and also say they do not have the equipment to do any capacity testing. PLEASE provide a FAA link to this new requirement. Paul Good Morning Paul, I am afraid that what Brian has said is true. If t you will read the Instructions for Continued Airworthiness that come with any new battery, you will find such requirements. You won't find a chapter and verse in the FARs that say you must capacity check a battery. What it does say is that maintenance must be done in accordance with manufacturers directives. The FAA is now pressuring all manufacturers and all applicants for an STC to provide information as to the Directions or Instructions for Continued Airworthiness. Therefore, any Instructions For Continued Air Worthiness become the law of the land unless you can prove to the Administrator that you have a "better way." I am not at all surprised that your FBO or IA does not have the current word. Why don't you ask them if they have ever attended one of the FAA's yearly IA clinics? Most have not. They renew their IAs by submitting an activity report. If they annual four airplanes per year, they need no formal training or checking. I certainly am NOT advocating tougher requirements for IA renewal, but it is a fact that the FAA has very little capability of getting the "word" out to people in the field. They do send many monthly communiques, but those who need the information the most rarely read those communiques. I agree that most shops do not have the equipment and are not complying with the capacity check requirements. To my knowledge, no one has yet gotten in trouble for non compliance, but it is still non compliance if the capacity check is not performed. Big Brother is out there, but he is very underfunded and does not always catch all omissions and deviations from the rule. How many FAA inspectors have looked at your airplane or gone through your paperwork? Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 ________________________________ Message 4 _____________________________________ Time: 08:18:34 AM PST US From: "Paul Messinger" Subject: AeroElectric-List: Battery life --> AeroElectric-List message posted by: "Paul Messinger" Much has been said about how battery life can be shortened by overcharging. Agreed; but what is important is how much is it shortened and under what conditions. So far no specifics have been suggested. Simply saying a specific battery failed in X months without also specific battery average temps and very important the charging voltage. Spam cans were designed for flooded cell batteries and short flights and thus have higher voltages to recharge the battery faster. The same is true for most automobiles. Taking a battery and giving it the recommended 3 stage treatment may make it a 10 year battery but in the real world of the AVERAGE experimental aircraft and average aircraft usage just what is the time to "Early death". Much has been said about overcharging after the battery has been fully charged and how the voltage needs to be reduced. All correct as I can recall. However Odyssey states that such over voltage can exist for up to 24 hours after full charge and then the voltage needs to be reduced. The charge voltage specified is 14.4 to 14.7 and this is well within the range of the regulators we use. So If I fly for 6 hours and then the next day use the battery for starting its no longer fully charged and in theory I can restart the 24 hour max limit. Poor conclusion; I agree but my point is 1-6 hour flights are far less than the 24 hour max imposed by the mfgr. Optima has different limits. The voltage limit is higher at 15.0 and the Time limit is less at 8 hours. Panasonic says 3 hours after charging current stabilizes, the battery is fully charged, thus saying that 3 hours at the higher voltage is OK. The charging voltage upper limit is 14.9. So we have upper limits of 14.7, 14.9 15.0 and time limits of 3, 8, and 24 hours. (This is for ABM type batteries but clearly they are different. So lets not paint with a broad brush and group batteries as AGP, vs Gell vs etc etc.) Thus its reasonable to conclude if your flights are 3 hours or less and your regulated alternator voltage is 14.4-14.7 you meet the requirements of the manufacturers of these three batteries for normal life times. No where can I find any data on specific shortening of life (times and conditions) other than the above Panasonic also discusses temperature compensation of charging vs battery life. 30 deg C compensation prolongs life by 5%,, 35C..10% and 40C..15%. Not much gained or lost and not worth the bother in most cases. Automotive external voltage regulators have built-in temperature compensation and if you install the regulator in the same area as the battery you get automatic compensation for free and no external temp monitor needed. (I would guess the B&C regulators require the temp sensor to compensate as that is an option) Paul ________________________________ Message 5 _____________________________________ Time: 08:30:38 AM PST US From: Subject: AeroElectric-List: Phillips Head Screws --> AeroElectric-List message posted by: < Further to the below, Canadian builders (and those close enough to cross-border shop) should be able to buy #6 x 1/2" galvanized Robertsons with a #0 head which, when used with a tinnerman, work nicely for RV trim and non-structural applications. These can be found in the aviation department of most Canadian Tire stores. (For non-GWN residents, this reference is to a large chain of stores which sell auto parts, hardware, sporting goods, and all sorts of stuff, including .... tires.)Jim Oke RV-6A, RV-3 Winnipeg, MB>> 6/20/2004 Hello Jim, Undoubtedly those Robertson screws with countersunk heads are with an 82 degree countersink angle -- -- the standard angle for common hardware store flat head screws. The standard aviation Tinnerman washer will have a 100 degree countersink dimple. There is no law prohibiting the mixing of hardware using the two different countersink angles, but the builder should be aware of the mismatch and the attendant loss of screw head to base material or washer contact that results. This mismatch can result in weakened fastener joints and open spaces that allow debris, moisture, and the resulting corrosion to exist. OC ________________________________ Message 6 _____________________________________ Time: 08:33:12 AM PST US From: "Paul Messinger" Subject: AeroElectric-List: engine hot starting --> AeroElectric-List message posted by: "Paul Messinger" Another lack of reading and understanding >>>This includes the need for prolonged attempts to start the engine. If it >>>takes more than a very few blades or 10 seconds there is a problem that >>>needs fixing. >> >>I guess you have never started a fuel-injected engine. I know my fuel >> injected engines like the back of my hand but sometimes it takes even me >> more than a few blades to get them to start when they are hot. I never JUST said a few blades, read it again I included 10 seconds to cover hot starts. I resent you comment about my knowledge of injected engines. I do know 99% of owners have a heck of a time with hot starts and most say they are using the acft manual procedure. Well I had problems with my Beech hot starting until I forgot the manual and was told how to start just about any brand or injected engine works every time and seldom more than a few seconds. > I have lots of time in injected aircraft including a couple of Beech 35's > (that I have owned) and its rare that hot starts need more then 5 seconds > using the proper hot starting procedure. However that was a cont and many > lycs have a different fuel system and can be a little harder to start but > that's a design shortcoming on the Lyc. It doesn't matter whether you think that the Lycoming injection system (actually Bendix RSA) is better or worse than Continental's (I happen to think it is better because it is a closed-loop servo system based on mass airflow measurement), the key point is that the problem I described CAN and DOES happen on a regular basis. I agree it happens on a regular basis but I disagree it needs to happen nearly as often. I have yet to see the fool proof hot start procedure in any manual. The best system in my opinion is the one on the S35 and its so unique its got a special section in the A&P manual. One simple dual spool rotary valve and easy to use and dirt simple. Works all the time! The Cont systems I have personal experience have a fuel pump return line back to the tank and the Lyc's have no return line. Thus not only is the fuel in the low pressure injecton lines boiled off but the engine driven pump heats its fuel and in the LYC case you cannot flush the hot fuel out so those designs are designed to be harder to start. > Even there 10 seconds is longer than needed. In a perfect world, maybe. If you feed the engine the proper mixture, it will fire and run. In a hot start that can be difficult and many OBAM aircraft have very tight cowls that retain heat on the ground causing the entire fuel system to become heat-soaked. Ensuring the proper mixture then becomes a crap shoot. They can be a real bitch to hot-start even if you hold your tongue right and the airplane gods are on your side. See above My experience appears to differ So perhaps you knew the magic incantation to make your engine start in three blades at all times but I think that the experience of the run-of-the-mill pilot will be different. I accept that it is possible that the pilot may have a period of extended cranking which will heat up and discharge the battery. That is the safest assumption and I prefer to design for that. So what and what is your point as the number of deep cycles in the battery is small compared to the battery design if you choose the proper battery. Paul ________________________________ Message 7 _____________________________________ Time: 08:48:32 AM PST US From: "Dan Morrow" Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: "Dan Morrow" The December 2003 and January 2004 issues of "The Aviation Consumer" contain interesting articles on batteries. They quote FAR 43.16 and 91.203 as recently amended to require the manufacturer's ICA's (Instructions for Continued Airworthiness) to be followed. Several of the battery manufacturers are now shipping new batteries with ICA's. Dan Morrow RV8A Building Empennage slowly ----- Original Message ----- From: "Paul Messinger" Subject: Re: AeroElectric-List: New FAA requirement???? > --> AeroElectric-List message posted by: "Paul Messinger" > > ""One needs to do capacity testing of the battery every 6 months or a year. > The FAA is now requiring that at annual for certified aircraft."" > > We all need to know about your above comment. I have asked both the local > FBO and a couple of IA's and no one has ever heard of such a requirement > and also say they do not have the equipment to do any capacity testing. > > PLEASE provide a FAA link to this new requirement. > > Paul > > ----- Original Message ----- > From: "Brian Lloyd" > To: > > --- ________________________________ Message 8 _____________________________________ Time: 09:04:13 AM PST US Subject: RE: AeroElectric-List: New FAA requirement???? From: "George Braly" --> AeroElectric-List message posted by: "George Braly" >>The FAA is now pressuring all manufacturers and all applicants for an STC to provide information as to the Directions or Instructions for Continued Airworthiness.<< Bob, It is not just "pressuring" - - the FAA absolutely requires that there be instructions for continuing airworthiness on all new STCs - - and they do actively review the proposed instructions before the issue the STC. It is probably a good rule - - if properly executed - - and a bad rule, otherwise. Regards, George ________________________________ Message 9 _____________________________________ Time: 09:07:11 AM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: "Paul Messinger" Thanks for the heads up. FAA is trying to keep up with NASA with the requirement for paperwork. IE It must exceed the height and weight of the craft before flight. I just read the Concord battery version of the ICA. Makes annuals at least 2 days just to test the battery and most of the time around here the battery must be physically removed to a heated room storage for 24 hours before the test. Paul > > Good Morning Paul, > > I am afraid that what Brian has said is true. > > If you will read the Instructions for Continued Airworthiness that come > with any new battery, you will find such requirements. > > You won't find a chapter and verse in the FARs that say you must capacity > check a battery. What it does say is that maintenance must be done in > accordance with manufacturers directives. > > The FAA is now pressuring all manufacturers and all applicants for an STC to > provide information as to the Directions or Instructions for Continued > Airworthiness. > > Therefore, any Instructions For Continued Air Worthiness become the law of > the land unless you can prove to the Administrator that you have a "better > way." > ________________________________ Message 10 ____________________________________ Time: 09:19:00 AM PST US From: "Dan Morrow" Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: "Dan Morrow" Sorry, that should have been FAR 91.403 not 91.203. Dan Morrow RV8A Building Empennage slowly ----- Original Message ----- From: "Dan Morrow" Subject: Re: AeroElectric-List: New FAA requirement???? > --> AeroElectric-List message posted by: "Dan Morrow" > > The December 2003 and January 2004 issues of "The Aviation Consumer" > contain interesting articles on batteries. They quote FAR 43.16 and 91.203 > as recently amended to require the manufacturer's ICA's (Instructions for > Continued Airworthiness) to be followed. Several of the battery > manufacturers are now shipping new batteries with ICA's. > > Dan Morrow > RV8A Building Empennage slowly > ----- Original Message ----- > From: "Paul Messinger" > To: > Subject: Re: AeroElectric-List: New FAA requirement???? > > > > --> AeroElectric-List message posted by: "Paul Messinger" > > > > > ""One needs to do capacity testing of the battery every 6 months or a > year. > > The FAA is now requiring that at annual for certified aircraft."" > > > > We all need to know about your above comment. I have asked both the local > > FBO and a couple of IA's and no one has ever heard of such a requirement > > and also say they do not have the equipment to do any capacity testing. > > > > PLEASE provide a FAA link to this new requirement. > > > > Paul > > > > ----- Original Message ----- > > From: "Brian Lloyd" > > To: > > > > > > > --- > > --- ________________________________ Message 11 ____________________________________ Time: 09:56:01 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: BobsV35B@aol.com In a message dated 6/20/04 11:04:42 AM Central Daylight Time, gwbraly@gami.com writes: Bob, It is not just "pressuring" - - the FAA absolutely requires that there be instructions for continuing airworthiness on all new STCs - - and they do actively review the proposed instructions before the issue the STC. Good Morning George, You are, as usual, completely correct. My thoughts were more toward the idea that the FAA is pressuring folks who hold older STCs to come up with an ICA for the older equipment. Do you have any idea what is the status of that effort? It is my understanding that the ICA rules have been on the books since about 1992, but have not been enforced until recently. Could open up a major can of worms! Happy Skies, Old Bob AKA Bob Siegfried Ancient Aviator Stearman N3977A Brookeridge Airpark LL22 Downers Grove, IL 60516 630 985-8502 ________________________________ Message 12 ____________________________________ Time: 11:30:12 AM PST US Subject: AeroElectric-List: Characterization of Westach 720-4a sensor From: irampil@notes.cc.sunysb.edu 06/20/2004 02:29:16 PM, Serialize complete at 06/20/2004 02:29:16 PM --> AeroElectric-List message posted by: irampil@notes.cc.sunysb.edu Greetings, Has anyone seen or developed a characterization of this tach sensor? It is a combined magnet/coil combo used to generate a pulse when a bit of iron speeds past(Ampere's law). In my case, I have 6 steel AN5 bolt heads/revolution roughly 3/32" from the sensor head at roughly 1000 inches/sec max. I'd like to know the expected output voltage and impedance so I can compute the input resistor for a 4n25. I need to divide the output pulse rate by 4 with a little TTL to get it into the frequency range for my tachometer system. Any advice? Ira N224XS flying, but due for a little panel rework ________________________________ Message 13 ____________________________________ Time: 11:40:14 AM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Battery data and etc --> AeroElectric-List message posted by: Brian Lloyd Paul Messinger wrote: > [stuff deleted] >>I have looked at it and, actually, it's not that different. It is an AGM >> battery using the spiral-wound construction technique. This type of >> battery was designed for UPS applications and has very low internal >> resistance right down to final discharge allowing UPS's to use much smaller >> and lighter batteries than they might otherwise need. The UPS designers >> don't expect them to get used much so they accept a design that represents >> a high level of abuse to the battery."" > > Well your reply relates to the Optima not the Odyssey (regarding > construction)and further the latter part of your comment is not at all > consistent with what both manufacturers say about their battery. In fact UPS > is not either of the two main points about their design that advertise. > > So you never bothered to READ and respond to what said or you would not > have confused the two manufacturers, And your reply indicated you read > neither mfgrs info for where they both say the intended use of the battery > is. No it isn't what the manufacturers currently advertise their batteries for but I am going back to the technology driving the design of small, high power density, AGM batteries. One of the problems with lead-acid batteries is a relatively high internal resistance. This means that the voltage sags when you pull current out of it and sags even more as the battery discharges. The traditional solution was to make the battery really big and heavy to increase the current delivery capability. Some people went in the direction of using NiCd batteries for their high power density (starting turbine engines comes to mind here) but they are very expensive and more difficult to charge safely. Then someone realized that if they could make the plate area of a lead-acid battery really big and reduce the plate spacing, they could pack a lot more capacity into a smaller package AND lower internal resistance. Voila! The spiral-wound AGM was born. The glass mat provides 100% effective insulation and plate spacing as well as holding the electrolyte. The plates are lead foil wrapped in a spiral which makes for very large surface area in a relatively small volume. As I recall, Gates was the first maker of these small, high power-density cells. The big market for these batteries was and is the small UPS market. The batteries are cheap to make but can deliver huge current for a short period of time. It is no small wonder that someone figured out that they are ideal for starting engines. You only need power for a few seconds at a time. So I stand by my early comments about UPS technology even if the manufacturer does not mention it in their literature. That is what drove the development of these compact AGMs. And even if Odyssey is not using spiral winding, the basic premise of using foil plates with a thin glass mat is still applicable. I would bet that Odyssey is not using spiral winding because of patent issues and had to come up with a way to do the same thing without having to pay royalties for the spiral winding technique. But I admit to a fair bit of speculation here. > EXAMPLE #2 >> Wrong. These problems affect battery life even when you are not >> discharging >the battery. > > What is WRONG with my statement and what does battery life have to do with > it?? Even if you do not significantly discharge the battery, the way you recharge it has a significant effect on battery life. When you crank an engine for 10 seconds drawing 200A, you are using only 0.55AH of the battery's capacity. (I will not get into Peukert's formula here as it will just bog the discussion down in a bunch of nitty-gritty detail that won't really help others understand. Regardless, I do understand Peukert's formula and how battery capacity varies with the rate of discharge.) That means that you have used only a few percent of the battery's charge. It is still almost fully charged. Now you throw it on a full charge regimen and you are guaranteed to overcharge the battery. You want to drop back to a float charge very early on if possible. So even if we are not going to deep-cycle the battery, we are in need of setting the charge and float voltages appropriate to the temperature of the battery for long battery life. This of course would lead into a discussion of it being better if the charge controller would monitor both battery voltage and charge current to determine that the battery is done charging. I think you mentioned that before and I agree with you that is the best way to do things. > EXAMPLE #3 >>Temp input is needed to set the proper charging voltage. > > > Well IF you look at most any battery mfgrs data they will tell you the ONLY > way to tell when to finish and go to the "float" mode is when the battery > current reaches a specific current (depending on the battery). Using battery > voltage under charge is at best a guess. In a constant-voltage charge, i.e. the voltage is held at the proper voltage for the absorption portion of the charge cycle, voltage tells you nothing so therefore, you are correct. You need to know either the prior state of the battery and can monitor the number of coulombs replaced (LA batteries are amazingly consistent in their coulombic efficiency), you need to monitor the end-of-charge charging current, or you need to monitor the time that the battery stays at the absorption charge voltage before switching to float voltage. The latter is a hack but it is surprisingly effective and many modern three-stage battery chargers use the technique. It turns out that the time differs a little from battery to battery but is is surprisingly consistent for a particular battery. The trick is to watch the battery recharge and monitor the time from when the battery reaches constant voltage until the charging current trails off to 5% of the 20-hour AH rating, e.g. 1A for a 20AH battery. Once you know that you can set the absorption time and pretty much forget it after that. But all of that aside, the proper absorption and float voltages are still dependent on temperature so you still need a temperature-sensing charge controller (voltage regulator). (BTW, the term "hack" is from the computer geek world and refers to a quick-and-dirty program that turns out to be surprisingly effective and useful in the long run.) > Paul > Perhaps one or more of the following fits :-) > > " I suffer fools badly" That is too bad. I have learned to suffer them well because today's fool MAY become a learned man through intelligent and reasoned discourse. > "Its hard to have a battle of wits with an unarmed man" Most assuredly you are a wit. Unfortunately I fear I have a tendency to be only half-right. Now that we have traded ideas and insults, may I buy you a beer at OSH so we can discuss battery and charging technology at greater length? -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 14 ____________________________________ Time: 12:18:50 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: Brian Lloyd Paul Messinger wrote: > --> AeroElectric-List message posted by: "Paul Messinger" > > ""One needs to do capacity testing of the battery every 6 months or a year. > The FAA is now requiring that at annual for certified aircraft."" > > We all need to know about your above comment. I have asked both the local > FBO and a couple of IA's and no one has ever heard of such a requirement > and also say they do not have the equipment to do any capacity testing. > > PLEASE provide a FAA link to this new requirement. Well, I feel a little stupid here. I was given the information by what I consider to be a reputable source but have now repeated the information without checking it. I can't find any reference to it on any of the FAA web sites I can get to but I have found references to capacity testing at the following sites: http://www.concordebattery.com/products/technical_info/servicealert_RF80-K.htm http://www.jfmeng.com/serv03.htm I will continue to try to find the original reference. -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 15 ____________________________________ Time: 01:03:47 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: engine hot starting --> AeroElectric-List message posted by: Brian Lloyd Paul Messinger wrote: > I do know 99% of owners have a heck of a time with hot starts and most say > they are using the acft manual procedure. Well I had problems with my Beech > hot starting until I forgot the manual and was told how to start just about > any brand or injected engine works every time and seldom more than a few > seconds. I agree that the hot-start technique usually provided in the pilot's handbook doesn't work very well. With Lycoming or Continental engines I find that the flooded start technique works quite well although it does require a bit of cranking. The technique I use is as follows: 1. Throttle and mixture full forward, i.e. full throttle and rich mixture. 2. Boost pump on until you see a stable fuel-flow indication. This means the vapor is purged from the system. 3. Mixture to idle-cut-off (ICO) and boost pump off. 4. Crank the engine. 5. When the engine fires, retard the throttle and advance the mixture. This technique works very reliably as the fuel lines and other components are cooled with fresh fuel and fuel vapor is purged from the lines. The problem now is that the engine is just about guaranteed to be flooded. Cranking with the throttle wide open admits the maximum amount of air and the mixture at ICO precludes any more fuel being admitted to the engine. As the engine cranks the mixture, which was initially too rich to fire, becomes progressively leaner until the engine fires. At that point the throttle is retarded and the mixture advanced to allow the engine to operate normally. >> It doesn't matter whether you think that the Lycoming injection system >> (actually Bendix RSA) is better or worse than Continental's (I happen to >> think it is better because it is a closed-loop servo system based on mass >> airflow measurement), the key point is that the problem I described CAN and >> DOES happen on a regular basis. > > I agree it happens on a regular basis but I disagree it needs to happen > nearly as often. I have yet to see the fool proof hot start procedure in any > manual. I agree with both of your statements. > The best system in my opinion is the one on the S35 and its so unique its > got a special section in the A&P manual. One simple dual spool rotary valve > and easy to use and dirt simple. Works all the time! It does have the advantage of being simpler than the Bendix RSA system but it has no mechanism to prevent the engine from getting too rich to operate. Leaving the boost pump in the high position can flood even a running engine. > The Cont systems I have personal experience have a fuel pump return line > back to the tank and the Lyc's have no return line. Thus not only is the > fuel in the low pressure injecton lines boiled off but the engine driven > pump heats its fuel and in the LYC case you cannot flush the hot fuel out so > those designs are designed to be harder to start. The "flooded start" procedure I outlined above works quite well but you may have to crank for 15 seconds or so depending on how much fuel you had to push through the injection system to purge the fuel vapor. I also like the fact that the Bendix fuel servo compensates for changes in fuel pressure and adjusts the flow accordingly. Also the mass airflow sensing causes the mixture to be more consistent as the aircraft changes altitude thus reducing cockpit workload for the pilot during climb and descent. Both systems work pretty well but they are very different. I do find it interesting to note that the popular modern aftermarket continuous-flow injection systems from Airflow Performance are based on the principles in the Bendix RSA system. The Bendix RSA fuel injection system is pretty old now and could use some updating but we all know how likely that is given the regulatory nature of the FAA. Bendix has no motivation to improve their system. >> In a perfect world, maybe. If you feed the engine the proper mixture, it >> will fire and run. In a hot start that can be difficult and many OBAM >> aircraft have very tight cowls that retain heat on the ground causing the >> entire fuel system to become heat-soaked. Ensuring the proper mixture then >> becomes a crap shoot. They can be a real bitch to hot-start even if you >> hold your tongue right and the airplane gods are on your side. > > See above My experience appears to differ Great! I am eager to learn. What is your technique? My technique works but I would much rather save the wear and tear on the starter and battery if possible. >> So perhaps you knew the magic incantation to make your engine start in three >> blades at all times but I think that the experience of the run-of-the-mill >> pilot will be different. I accept that it is possible that the pilot may >> have a period of extended cranking which will heat up and discharge the >> battery. That is the safest assumption and I prefer to design for that. > > So what and what is your point as the number of deep cycles in the battery > is small compared to the battery design if you choose the proper battery. If you recall, I was pointing out how a thermal runaway event in a battery could be initiated on a hot day with a prolonged cranking event and how a high initial charge rate could exacerbate the problem. Temperature sensing on the battery would reduce the voltage and hence the charge rate thus saving the battery. I wasn't talking about deep cycles at all. I think that we got off on the wrong foot when I pointed out that AGMs have shorter lifetimes in deep cycle service than do gell-cells. I agree that deep cycle service is unusual in an aircraft except where there is a failure and that is not normal operation. But I did want to emphasize that there is confusion in people's minds between gell-cell batteries and AGM batteries and that you need to adjust the charging system to accommodate the type of battery you have installed in your aircraft and the temperature at which that battery is operating. One thing that *is* worth considering is that the difference between charge and float voltages in gell-cell batteries are much closer together than are the charge and float voltages for flooded-cell and AGM batteries. If you are going to have a charging system with only a single set-point, I think you may find that the gell-cell lives longer than the AGM in that environment. In my RV-4 I installed an over-sized gell-cell that would power my e-buss for 4 hours, the normal fuel duration of the aircraft. I knew that if I got to the end of the battery capacity, I probably had other, more pressing problems to deal with. The point is that the bigger gell-cell was able to crank the O-320 very happily thus validating the "bigger battery means more current" philosophy. And you may be right that the Odyssey battery is the be-all and end-all of batteries. It may be so robustly constructed that it takes the abuse without damage so all this may be a moot point. But I still believe that one should operate all the devices in an aircraft as conservatively as possible. It won't hurt your Odyssey battery to perform a proper three-stage charge cutting off to the proper float voltage, will it? Pax? -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 16 ____________________________________ Time: 01:05:15 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: New FAA requirement???? --> AeroElectric-List message posted by: Brian Lloyd Dan Morrow wrote: > --> AeroElectric-List message posted by: "Dan Morrow" > > The December 2003 and January 2004 issues of "The Aviation Consumer" > contain interesting articles on batteries. They quote FAR 43.16 and 91.203 > as recently amended to require the manufacturer's ICA's (Instructions for > Continued Airworthiness) to be followed. Several of the battery > manufacturers are now shipping new batteries with ICA's. Thank you Dan. That is where I remember seeing the requirement for capacity testing. -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 17 ____________________________________ Time: 01:14:16 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: Characterization of Westach 720-4a sensor --> AeroElectric-List message posted by: Brian Lloyd irampil@notes.cc.sunysb.edu wrote: > I'd like to know the expected output voltage and impedance so I can > compute the > input resistor for a 4n25. I need to divide the output pulse rate by 4 > with a little TTL to > get it into the frequency range for my tachometer system. > > Any advice? Well, you can look at it with a scope. That takes all the guesswork out of the problem. You can amplify the signal with an op-amp and use some small-signal or a pair of back-to-back zener diodes in the feedback loop to square the peaks. The op-amp will operate more-or-less open-loop until the diodes or the zeners conduct. With an appropriate offset you should get a nice pulse that will make TTL or CMOS happy. A fast-recovery, no-latch-up op-amp running from a single-ended supply should work just peachy. This is an old technique for applying an analog pulse to digital circuitry. -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 18 ____________________________________ Time: 05:23:47 PM PST US Subject: RE: AeroElectric-List: engine hot starting From: "George Braly" --> AeroElectric-List message posted by: "George Braly" Brian, Your technique is common for hot starts. It is not the technique that makes use of knowledge as to what the real problem is. And it is a technique that can be very dangerous and cause a fire that can and has consumed an airplane. Getting fuel flow indications may indicate that "vapor is purged" - - but is not at all an indication that you are not going to vapor lock about 3-5 seconds after the engine fires up - - and then promptly stops. The reasons these engines are hard to start when HOT is very simple. The fuel pump core is HOT - - so hot that when new fuel hits the core of the engine driven fuel pump it flashes to vapor and vapor locks the inlet to the fuel pump. Until you sufficiently cool off the core of the fuel pump it will ALWAYS - - ALWAYS vapor lock. You either have to: 1) cool off the core of the engine driven fuel pump (easy with a TCM fuel system); or, 2) You have to use the electric boost pump to keep the engine running until the core of the engine driven pump does cool off enough to quit flashing the incoming fuel to vapor (typical Lycoming and some twin Cessna techniques). After the fuel pump core components are cooled off, the engine will actually start better than when cold. Regards, George -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Brian Lloyd Subject: Re: AeroElectric-List: engine hot starting --> AeroElectric-List message posted by: Brian Lloyd Paul Messinger wrote: > I do know 99% of owners have a heck of a time with hot starts and most say > they are using the acft manual procedure. Well I had problems with my Beech > hot starting until I forgot the manual and was told how to start just about > any brand or injected engine works every time and seldom more than a few > seconds. I agree that the hot-start technique usually provided in the pilot's handbook doesn't work very well. With Lycoming or Continental engines I find that the flooded start technique works quite well although it does require a bit of cranking. The technique I use is as follows: 1. Throttle and mixture full forward, i.e. full throttle and rich mixture. 2. Boost pump on until you see a stable fuel-flow indication. This means the vapor is purged from the system. 3. Mixture to idle-cut-off (ICO) and boost pump off. 4. Crank the engine. 5. When the engine fires, retard the throttle and advance the mixture. This technique works very reliably as the fuel lines and other components are cooled with fresh fuel and fuel vapor is purged from the lines. The problem now is that the engine is just about guaranteed to be flooded. Cranking with the throttle wide open admits the maximum amount of air and the mixture at ICO precludes any more fuel being admitted to the engine. As the engine cranks the mixture, which was initially too rich to fire, becomes progressively leaner until the engine fires. At that point the throttle is retarded and the mixture advanced to allow the engine to operate normally. >> It doesn't matter whether you think that the Lycoming injection system >> (actually Bendix RSA) is better or worse than Continental's (I happen to >> think it is better because it is a closed-loop servo system based on mass >> airflow measurement), the key point is that the problem I described CAN and >> DOES happen on a regular basis. > > I agree it happens on a regular basis but I disagree it needs to happen > nearly as often. I have yet to see the fool proof hot start procedure in any > manual. I agree with both of your statements. > The best system in my opinion is the one on the S35 and its so unique its > got a special section in the A&P manual. One simple dual spool rotary valve > and easy to use and dirt simple. Works all the time! It does have the advantage of being simpler than the Bendix RSA system but it has no mechanism to prevent the engine from getting too rich to operate. Leaving the boost pump in the high position can flood even a running engine. > The Cont systems I have personal experience have a fuel pump return line > back to the tank and the Lyc's have no return line. Thus not only is the > fuel in the low pressure injecton lines boiled off but the engine driven > pump heats its fuel and in the LYC case you cannot flush the hot fuel out so > those designs are designed to be harder to start. The "flooded start" procedure I outlined above works quite well but you may have to crank for 15 seconds or so depending on how much fuel you had to push through the injection system to purge the fuel vapor. I also like the fact that the Bendix fuel servo compensates for changes in fuel pressure and adjusts the flow accordingly. Also the mass airflow sensing causes the mixture to be more consistent as the aircraft changes altitude thus reducing cockpit workload for the pilot during climb and descent. Both systems work pretty well but they are very different. I do find it interesting to note that the popular modern aftermarket continuous-flow injection systems from Airflow Performance are based on the principles in the Bendix RSA system. The Bendix RSA fuel injection system is pretty old now and could use some updating but we all know how likely that is given the regulatory nature of the FAA. Bendix has no motivation to improve their system. >> In a perfect world, maybe. If you feed the engine the proper mixture, it >> will fire and run. In a hot start that can be difficult and many OBAM >> aircraft have very tight cowls that retain heat on the ground causing the >> entire fuel system to become heat-soaked. Ensuring the proper mixture then >> becomes a crap shoot. They can be a real bitch to hot-start even if you >> hold your tongue right and the airplane gods are on your side. > > See above My experience appears to differ Great! I am eager to learn. What is your technique? My technique works but I would much rather save the wear and tear on the starter and battery if possible. >> So perhaps you knew the magic incantation to make your engine start in three >> blades at all times but I think that the experience of the run-of-the-mill >> pilot will be different. I accept that it is possible that the pilot may >> have a period of extended cranking which will heat up and discharge the >> battery. That is the safest assumption and I prefer to design for that. > > So what and what is your point as the number of deep cycles in the battery > is small compared to the battery design if you choose the proper battery. If you recall, I was pointing out how a thermal runaway event in a battery could be initiated on a hot day with a prolonged cranking event and how a high initial charge rate could exacerbate the problem. Temperature sensing on the battery would reduce the voltage and hence the charge rate thus saving the battery. I wasn't talking about deep cycles at all. I think that we got off on the wrong foot when I pointed out that AGMs have shorter lifetimes in deep cycle service than do gell-cells. I agree that deep cycle service is unusual in an aircraft except where there is a failure and that is not normal operation. But I did want to emphasize that there is confusion in people's minds between gell-cell batteries and AGM batteries and that you need to adjust the charging system to accommodate the type of battery you have installed in your aircraft and the temperature at which that battery is operating. One thing that *is* worth considering is that the difference between charge and float voltages in gell-cell batteries are much closer together than are the charge and float voltages for flooded-cell and AGM batteries. If you are going to have a charging system with only a single set-point, I think you may find that the gell-cell lives longer than the AGM in that environment. In my RV-4 I installed an over-sized gell-cell that would power my e-buss for 4 hours, the normal fuel duration of the aircraft. I knew that if I got to the end of the battery capacity, I probably had other, more pressing problems to deal with. The point is that the bigger gell-cell was able to crank the O-320 very happily thus validating the "bigger battery means more current" philosophy. And you may be right that the Odyssey battery is the be-all and end-all of batteries. It may be so robustly constructed that it takes the abuse without damage so all this may be a moot point. But I still believe that one should operate all the devices in an aircraft as conservatively as possible. It won't hurt your Odyssey battery to perform a proper three-stage charge cutting off to the proper float voltage, will it? Pax? -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. == == == == ________________________________ Message 19 ____________________________________ Time: 08:55:50 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: engine hot starting --> AeroElectric-List message posted by: Brian Lloyd George Braly wrote: > Your technique is common for hot starts. > > It is not the technique that makes use of knowledge as to what the real > problem is. And it is a technique that can be very dangerous and cause > a fire that can and has consumed an airplane. As for the technique: 1. it has been recommended by a number of respected sources; 2. it works. OTOH, I defer to you. Certainly if anyone knows aircraft fuel injection systems, you do. > Until you sufficiently cool off the core of the fuel pump it will ALWAYS > - - ALWAYS vapor lock. Good point. This is a common problem with the O-540 in my carburated Comanche. No reason the problem wouldn't also exist with the engine-driven fuel pump in the IO-540. > You either have to: > > 1) cool off the core of the engine driven fuel pump (easy with a TCM > fuel system); or, > > 2) You have to use the electric boost pump to keep the engine running > until the core of the engine driven pump does cool off enough to quit > flashing the incoming fuel to vapor (typical Lycoming and some twin > Cessna techniques). Good point. I will leave the boost pump on in the flooded start procedure instead of turning it off. > After the fuel pump core components are cooled off, the engine will > actually start better than when cold. Unfortunately there is no good way to cool off the fuel pump in the Bendix RSA injection system short of pouring fuel into the induction system. So I am interested in a better way to start the engine. What suggestions do you have? -- Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 http://www.lloyd.com St. Thomas, VI 00802 +1.340.998.9447 (voice) +1.360.838.9669 (fax) There is a time to laud one's country and a time to protest. A good citizen is prepared to do either as the need arises. ________________________________ Message 20 ____________________________________ Time: 09:56:27 PM PST US Subject: AeroElectric-List: Alternator Failure From: "David Chalmers" --> AeroElectric-List message posted by: "David Chalmers" Well today I had an alternator failure on a cross country. Luckily I had installed Bob's low voltage warning light and it started flashing in front of me as soon as the alternator failed. After landing and assessing the options I was able to fly back to home base using just the battery and minimal equipment. Only reason I felt confident doing this was because I have subscribed to Bob's advice and change the battery every year so I knew what it was close to rated capacity. Thanks Bob for your advice over the years - it paid off for me today. Without the low voltage warning or the known-healthy battery I would have been stranded in the middle of nowhere. Dave Chalmers Redmond, WA ________________________________ Message 21 ____________________________________ Time: 10:23:35 PM PST US Subject: AeroElectric-List: 3 stage voltage regulator From: Christopher J Fortin --> AeroElectric-List message posted by: Christopher J Fortin Hi Brian, I was wondering if this regulator -Cruzpro SAR20- might be suitable for use in a plane. You can get it for less than $140 here in the states. http://www.cruzpro.com/sar20.html Chris Fortin N813CJ reserved ________________________________ Message 22 ____________________________________ Time: 11:52:04 PM PST US From: "James Foerster" Subject: AeroElectric-List: Re: Characterization of Westach 720-4a sensor --> AeroElectric-List message posted by: "James Foerster" Ira, Why do you want to use a 4n25? This is a gallium-arsenide infrared diode driving transistor in a six pin package, usually used as a signal isolator. This one is good for 2500 volts. Since the coil of your transducer is already isolated, I don't see why you took this path. I suspect that I am missing some information about this problem that led you in this direction. Brian Lloyd is right, of course, that an oscilloscope would directly measure your voltage. I suspect that the impedance is about equal to the DC resistance of the coil in the device. You could measure voltage open circuit with the scope, then put a non-inductive resistor across the input and calculate the resistance of the source knowing the reduced voltage with load. Don't try to calculate your voltage. The change in reluctance in this circuit, which gives the change in magnetic field (B field) is not linear ,as in your calculation that the maximum velocity is 1000 inches per second. It is also not sinusoidal, and thus not practical to calculate. Just use an amplifier which has high gain, and it will make no difference. I'd try to use a comparator--op amp designed to run open loop and output to the supply rails--but Bryan had a more elegant solution. At the frequencies involved, either way would work. I just searched the Westach site, and I can't find this particular unit. I had hoped that they would have some suggested circuits for the sensor. Jim Foerster