---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 11/23/03: 30 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:47 AM - Re: Magneto Relpacements (James E. Clark) 2. 05:38 AM - Re: RG Battery source (LarryRobertHelming) 3. 08:03 AM - Re: Basics (Robert L. Nuckolls, III) 4. 08:14 AM - Re: Magneto Relpacements (Jim Sower) 5. 09:01 AM - Re: Magneto Relpacements (Tom Caruthers) 6. 11:52 AM - Re: Magneto Relpacements (Jim Sower) 7. 12:18 PM - EI and Prop Vib was: Magneto Replacement (Treff, Arthur) 8. 12:51 PM - Acronyms () 9. 01:04 PM - Re: Acronyms (David Swartzendruber) 10. 01:04 PM - Re: Acronyms (Ageless Wings) 11. 01:15 PM - Re: Acronyms (Neville Kilford) 12. 01:27 PM - Re: Magneto Relpacements (Robert L. Nuckolls, III) 13. 01:50 PM - Re: Acronyms (Robert L. Nuckolls, III) 14. 02:26 PM - re OBAM () 15. 04:36 PM - Re: Magneto Relpacements (George Braly) 16. 04:51 PM - Re: EI and Prop Vib was: Magneto Replacement (Jim Sower) 17. 06:01 PM - re Electronic Ignition () 18. 07:01 PM - Re: re Electronic Ignition (George Braly) 19. 07:13 PM - Re: Magneto Relpacements (Jim Sower) 20. 07:33 PM - Re: Magneto Relpacements (Dan Branstrom) 21. 07:41 PM - Re: Magneto Relpacements (James E. Clark) 22. 08:06 PM - Re: Magneto Relpacements (James E. Clark) 23. 08:11 PM - Re: Magneto Relpacements (George Braly) 24. 08:16 PM - Re: EI and Prop Vib was: Magneto Replacement (James E. Clark) 25. 08:34 PM - Re: Bob, need info on microair com/xpdr (Rick Fogerson) 26. 08:47 PM - Re: re Electronic Ignition (James E. Clark) 27. 09:47 PM - Re: Bob, need info on microair com/xpdr (Robert L. Nuckolls, III) 28. 09:47 PM - Odyssey battery (Greg Milner) 29. 10:24 PM - Re: Odyssey battery (Robert L. Nuckolls, III) 30. 10:47 PM - Re: Magneto Relpacements (George Braly) ________________________________ Message 1 _____________________________________ Time: 04:47:58 AM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "James E. Clark" Dj, It is not that they are "not okay to use" but that there are LIMITATIONS on their use. Particularly, the Hartzell Constant Speed props have RPM "do not exceed" RPMs and "do not dwell long in this zone" RPMs. Basically one must reduce RPM to under 2700 (say about 2600) after take-off and therre are some RPM/manifold pressure combinations down lower in the power cover where one is to avoid continuous operation. In reality these "limitations" are not a big deal in that they are in areas where you would not likely have the power set for very long anyway. There is a HARD STOP required for the top RPM (I don't remember the exact number at the moment but say 2750). The logic (simply put) is that the pulses you get using EI cause a DIFFERENT burn and thus a different "ping" on the engine (probably a sharper bigger bang (??) and thus the improvement in performance). This all in turn causes the prop to resonate at a DIFFERENT harmonic. Hit the right harmonic ON ANYTHING and it shakes apart!! The harmonic in this case is something like 8th order as I recall(I could be wrong) but still, if they think there is the LEAST BIT OF A CHANCE that you could break that thing swing out front, they are going to warn against and rightfully so. There are propos that are made of different material (wood, composites, etc) that don't resonate like metal and this the circumstances are different. Also, I mentioned the Hartzell but the Sensenich has a similar issue on the metal prop that goes with the O-320 I think. Summary from my view ... don't sweat it. James O-320/ElectroAir EI with wood Ed Sterba being flown O-360/Plasma II+ EI with Hatzell C/S being built O-360/Plasma II EI with Hartzell C/S ... passenger to OSH in 2002 <<>> > Hi Bob, > I've heard that some props are not okay to use > with electronic ignition due to the harmonic vibrations > being different than with mags. Know anything about this? > > -Dj > > -- > Dj Merrill Thayer School of Engineering > ThUG Sr. Unix Systems Administrator 8000 Cummings Hall > deej@thayer.dartmouth.edu - N1JOV Dartmouth College, Hanover, NH 03755 > > "On the side of the software box, in the 'System Requirements' section, > > ________________________________ Message 2 _____________________________________ Time: 05:38:19 AM PST US From: "LarryRobertHelming" Subject: Re: AeroElectric-List: RG Battery source --> AeroElectric-List message posted by: "LarryRobertHelming" Try www.digikey.com. Cost was less than $50 which included shipping and handling. Panasonic was brand name I got. Not flying yet but it works great on the bench and fits into Vans PC680 firewall mount battery box. Indiana Larry, RV7 Tip-up TMX-O-360 ACS2002 Dynon CNS430 Digitrak On Finish Kit ----- Original Message ----- From: "Dave Morris" Subject: AeroElectric-List: RG Battery source > --> AeroElectric-List message posted by: Dave Morris > > At 02:04 PM 11/16/2003 -0600, Bob wrote: > > > levels. You can buy 17 a.h. RG batteries for as low as $45 over > > the counter. In spite of weight penalty (15# battery versus 4# > > Where? > > Thanks, > Dave > > ________________________________ Message 3 _____________________________________ Time: 08:03:40 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Basics --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:52 PM 11/22/2003 -0600, you wrote: >--> AeroElectric-List message posted by: Dave Morris > >Bob, > >I know it's gotta be painful to have to keep re-hashing concepts over and >over with us newbies. Thanks so much for the time you spend teaching us! > >Dave Not at all. If I were employed by a university or other formal education institution, I'd get a new class every semester. I do multiple weekend seminars every year that all begin at the same place. If one aspires to the title there are duties that come with it. It's not a problem. Bob . . . ________________________________ Message 4 _____________________________________ Time: 08:14:51 AM PST US From: Jim Sower Subject: Re: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: Jim Sower <... have RPM "do not exceed" RPMs and "do not dwell long in this zone" RPMs ... HARD STOP required for the top RPM ...> What do these have to do with EI? <... The logic (simply put) is that the pulses you get using EI cause a DIFFERENT burn and thus a different "ping" on the engine (probably a sharper bigger bang (??) and thus the improvement in performance) ...> This statement is based on ... what?? Engineering research or brain fart? Or what? <... (probably a sharper bigger bang (??) ...> I know that EI provides MUCH more optimum spark timing for rpm than mags (around 35-40 deg as compared with mags which are bolted on at 25 deg or so) and that CD is a much higher quality and more reliable spark (and therefore better flame front) than mags produce. Advanced timing starts combustion early enough that you get full benefit of the power stroke and don't dump still-trying-to-work combustion gasses over the side (think improved fuel efficiency and exhaust valve life). <... Hit the right harmonic ON ANYTHING and it shakes apart!! ...> Agreed. Harmonics can be devastating. That said, what is the credible (key word here) evidence that replacing 1930s technology mags with a device that provides much higher quality ignition at optimum timing is going to cause these harmonics? No offense, but I'm going to need specific documentation on this one. I'm reluctant to get real shrill absent credible engineering to back up the rumors ... Jim S. "James E. Clark" wrote: > --> AeroElectric-List message posted by: "James E. Clark" > > Dj, > > It is not that they are "not okay to use" but that there are LIMITATIONS on > their use. > > Particularly, the Hartzell Constant Speed props have RPM "do not exceed" > RPMs and "do not dwell long in this zone" RPMs. Basically one must reduce > RPM to under 2700 (say about 2600) after take-off and therre are some > RPM/manifold pressure combinations down lower in the power cover where one > is to avoid continuous operation. In reality these "limitations" are not a > big deal in that they are in areas where you would not likely have the power > set for very long anyway. > > There is a HARD STOP required for the top RPM (I don't remember the exact > number at the moment but say 2750). > > The logic (simply put) is that the pulses you get using EI cause a DIFFERENT > burn and thus a different "ping" on the engine (probably a sharper bigger > bang (??) and thus the improvement in performance). This all in turn causes > the prop to resonate at a DIFFERENT harmonic. Hit the right harmonic ON > ANYTHING and it shakes apart!! The harmonic in this case is something like > 8th order as I recall(I could be wrong) but still, if they think there is > the LEAST BIT OF A CHANCE that you could break that thing swing out front, > they are going to warn against and rightfully so. > > There are propos that are made of different material (wood, composites, etc) > that don't resonate like metal and this the circumstances are different. > > Also, I mentioned the Hartzell but the Sensenich has a similar issue on the > metal prop that goes with the O-320 I think. > > Summary from my view ... don't sweat it. > > James > O-320/ElectroAir EI with wood Ed Sterba being flown > O-360/Plasma II+ EI with Hatzell C/S being built > O-360/Plasma II EI with Hartzell C/S ... passenger to OSH in 2002 > > <<>> > > Hi Bob, > > I've heard that some props are not okay to use > > with electronic ignition due to the harmonic vibrations > > being different than with mags. Know anything about this? > > ________________________________ Message 5 _____________________________________ Time: 09:01:07 AM PST US From: Tom Caruthers Subject: Re: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: Tom Caruthers Dear Jim, Hartzell Propeller wrote the following to Van's Aircraft about this subject. This is part of the letter. "Propeller vibration characteristics and stress amplitudes on a reciprocating engine installation are primarily mechanically generated by the engine. Any modification to the standard engine configuration to include high compression pistons, electronic ignition, FADEC, tuned induction and exhaust, and turbocharging or turbonormalizing have the potential to adversely effect the propeller vibration characteristics and stress amplitudes. Hartzell Propeller, therefore, does not endorse any such engine modification unless the specific engine and propeller configurations have been tested and found to be vibrationally acceptable according to FAR 23.907." As a builder of an experimental aircraft, you are free to make your own decision. I will not take the chance by ignoring the propeller manufacturer's advise. Does this mean I will not install electronic ignition? NO! What this means is that I will follow their recommendations about the operation of an engine so equipped. Just my opinion. Tom --- Jim Sower wrote: > --> AeroElectric-List message posted by: Jim Sower > > > <... have RPM "do not exceed" RPMs and "do not dwell > long in this zone" RPMs ... HARD > STOP required for the top RPM ...> > What do these have to do with EI? > > <... The logic (simply put) is that the pulses you > get using EI cause a DIFFERENT burn > and thus a different "ping" on the engine (probably > a sharper bigger bang (??) and thus > the improvement in performance) ...> > This statement is based on ... what?? Engineering > research or brain fart? Or what? > > <... (probably a sharper bigger bang (??) ...> > I know that EI provides MUCH more optimum spark > timing for rpm than mags (around 35-40 > deg as compared with mags which are bolted on at 25 > deg or so) and that CD is a much > higher quality and more reliable spark (and > therefore better flame front) than mags > produce. Advanced timing starts combustion early > enough that you get full benefit of > the power stroke and don't dump still-trying-to-work > combustion gasses over the side > (think improved fuel efficiency and exhaust valve > life). > > <... Hit the right harmonic ON ANYTHING and it > shakes apart!! ...> > Agreed. Harmonics can be devastating. That said, > what is the credible (key word here) > evidence that replacing 1930s technology mags with a > device that provides much higher > quality ignition at optimum timing is going to cause > these harmonics? No offense, but > I'm going to need specific documentation on this > one. > > I'm reluctant to get real shrill absent credible > engineering to back up the rumors ... > Jim S. > > "James E. Clark" wrote: > > > --> AeroElectric-List message posted by: "James E. > Clark" > > > > Dj, > > > > It is not that they are "not okay to use" but that > there are LIMITATIONS on > > their use. > > > > Particularly, the Hartzell Constant Speed props > have RPM "do not exceed" > > RPMs and "do not dwell long in this zone" RPMs. > Basically one must reduce > > RPM to under 2700 (say about 2600) after take-off > and therre are some > > RPM/manifold pressure combinations down lower in > the power cover where one > > is to avoid continuous operation. In reality these > "limitations" are not a > > big deal in that they are in areas where you would > not likely have the power > > set for very long anyway. > > > > There is a HARD STOP required for the top RPM (I > don't remember the exact > > number at the moment but say 2750). > > > > The logic (simply put) is that the pulses you get > using EI cause a DIFFERENT > > burn and thus a different "ping" on the engine > (probably a sharper bigger > > bang (??) and thus the improvement in > performance). This all in turn causes > > the prop to resonate at a DIFFERENT harmonic. Hit > the right harmonic ON > > ANYTHING and it shakes apart!! The harmonic in > this case is something like > > 8th order as I recall(I could be wrong) but still, > if they think there is > > the LEAST BIT OF A CHANCE that you could break > that thing swing out front, > > they are going to warn against and rightfully so. > > > > There are propos that are made of different > material (wood, composites, etc) > > that don't resonate like metal and this the > circumstances are different. > > > > Also, I mentioned the Hartzell but the Sensenich > has a similar issue on the > > metal prop that goes with the O-320 I think. > > > > Summary from my view ... don't sweat it. > > > > James > > O-320/ElectroAir EI with wood Ed Sterba being > flown > > O-360/Plasma II+ EI with Hatzell C/S being built > > O-360/Plasma II EI with Hartzell C/S ... passenger > to OSH in 2002 > > > > <<>> > > > Hi Bob, > > > I've heard that some props are not okay > to use > > > with electronic ignition due to the harmonic > vibrations > > > being different than with mags. Know anything > about this? > > > > > > > Click on the > this > generous > _-> > - > Contributions > any other > Forums. > > http://www.matronics.com/chat > > http://www.matronics.com/subscription > http://www.matronics.com/FAQ/AeroElectric-List.htm > http://www.matronics.com/archives > http://www.matronics.com/photoshare > http://www.matronics.com/emaillists > > > > > __________________________________ Free Pop-Up Blocker - Get it now http://companion.yahoo.com/ ________________________________ Message 6 _____________________________________ Time: 11:52:18 AM PST US From: Jim Sower Subject: Re: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: Jim Sower <... Any modification to the standard engine configuration to include high compression pistons, electronic ignition, FADEC, tuned induction and exhaust, and turbocharging or turbonormalizing have the potential to adversely effect the propeller vibration characteristics and stress amplitudes ...> That pretty well covers the ground. Any departure from seventy-year-old technology has the potential to adversely effect Hartzel props. <... I will follow their recommendations about the operation of an engine so equipped ...> Which might be?.... No specifics so far. Just a sweeping, unsupported generalities. For my own part, I regard that statement much less as a caution against the developments listed than a compelling reason to stay away from Hartzell props and not expose myself (or my airplane or my family) to what appears to be their singularly hidebound approach to engineering.. But that's just me ... Jim S. ________________________________ Message 7 _____________________________________ Time: 12:18:02 PM PST US Subject: AeroElectric-List: EI and Prop Vib was: Magneto Replacement From: "Treff, Arthur" --> AeroElectric-List message posted by: "Treff, Arthur" <... I've read that some props aren't a good match for an EI due to the different harmonic vibrations with the EI versus the mag ignition ...> Then Jim Wrote: News to me. I've never heard anything like that at all. Can't imagine how improved combustion would cause vibration. Of course Lycs by their nature shake and rattle so hell wouldn't have it - but to lay that problem at the door of the only technological improvement those engines have seen since 1933 is a bit of a stretch IMO. No offense, but I'll need some documentation on that one. One could argue that I'm a true believer :o) ... Jim S. All, Seems that with the advent of FADEC and Electronic Ignition, the old Lyc's are putting out more power. This has resulted in different propellor resonances which seem to have arisen due to more effective engine combustion, i.e., each cylinder's 'bang' is a tad more powerful. Hartzell and a few of the composite prop guys are re-thinking their continuous operating RPM ranges and resonant 'cautionary zones' to limit constant operation on engines equipped with EI and/or FADEC, and this is starting to gain momentum in terms of documentation. For example, go to this link on the Van's Aircraft website on engine and prop combinations, note the blue ** next to the Hartzell CS prop and all the disclaimers re: FADEC and EI in the footnotes. The prop people seem to be scrambling to limit their liability exposure until they can test these combinations on Lyc's. http://www.vansaircraft.com/cgi-bin/catalog.cgi?ident=1069617493-298-15&browse=props&product=csprop-hartzell When my mags go south, I too will be adding EI, however my prop decision today will weigh heavily on how well the manufacturer stands behind the configuration of my engine in the future. Based on what I know today, it'll probably not be a Hartzell. Not a reason to sweat, and certainly not a reason to stay away from Electronic Ignition, just something to be informed about. Remember, the props of today were designed and tested to be driven by the engines of yesterday, and EI is a (relatively) new iteration for our aircraft engines which were designed over 50 years ago. It's just the normal growing pains aviation is going thru. I'd be willing to bet that all this hoopla around eng/prop/FADEC/EI combinations will die down within a few years, once Hartzell catches up to the groundswell. Heck, they make racing props for really tricked out ships at Reno, and I believe that they've spun more than a few custom blades for guys like Bruce Bohannon, so they'll get there eventually. Art Treff ________________________________ Message 8 _____________________________________ Time: 12:51:25 PM PST US From: Subject: AeroElectric-List: Acronyms --> AeroElectric-List message posted by: Hi Bob-- At the risk of demonstrating that I'm the only dummy on the list that doesn't know the score [anyone want to go Snipe hunting?], please explain what OBAM stands for. I've thought of a couple of possibilities, none of which make sense or are appropriate for a family setting. Please get me out of the quandry. Jim ________________________________ Message 9 _____________________________________ Time: 01:04:09 PM PST US From: "David Swartzendruber" Subject: Re: AeroElectric-List: Acronyms --> AeroElectric-List message posted by: "David Swartzendruber" OBAM is Owner Built And Maintained. do not archive > > please explain what OBAM stands for. > Jim ________________________________ Message 10 ____________________________________ Time: 01:04:49 PM PST US From: "Ageless Wings" Subject: RE: AeroElectric-List: Acronyms --> AeroElectric-List message posted by: "Ageless Wings" Hi, Jim.. >>please explain what OBAM stands for<< No problem..I'm 60 years old, it was a new one to me, too, and only find out myself this year! Owner Built And Maintained! Harley >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of >> jimk36@comcast.net >> Sent: Sunday, November 23, 2003 3:51 PM >> To: aeroelectric-list@matronics.com >> Subject: AeroElectric-List: Acronyms >> >> >> --> AeroElectric-List message posted by: >> >> Hi Bob-- >> >> At the risk of demonstrating that I'm the only dummy on the list >> that doesn't know the score [anyone want to go Snipe hunting?], >> please explain what OBAM stands for. I've thought of a couple of >> possibilities, none of which make sense or are appropriate for a >> family setting. Please get me out of the quandry. >> >> Jim >> >> >> ========= >> ========= >> ========= >> ========= >> >> >> >> >> ________________________________ Message 11 ____________________________________ Time: 01:15:38 PM PST US From: "Neville Kilford" Subject: Re: AeroElectric-List: Acronyms --> AeroElectric-List message posted by: "Neville Kilford" Jim, Don't feel that way, everyone who has anything to do with aviation wanders around wondering what the latest bunch of acronyms might mean. OBAM -- owner-built and maintained. FWIW, it wasn't a term I'd heard until I joined this list. Cheers. Nev -- Jodel D150 in progress UK ----- Original Message ----- From: Subject: AeroElectric-List: Acronyms > --> AeroElectric-List message posted by: > > Hi Bob-- > > At the risk of demonstrating that I'm the only dummy on the list that doesn't know the score [anyone want to go Snipe hunting?], please explain what OBAM stands for. I've thought of a couple of possibilities, none of which make sense or are appropriate for a family setting. Please get me out of the quandry. > > Jim > > ________________________________ Message 12 ____________________________________ Time: 01:27:47 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > I've heard that some props are not okay to use > with electronic ignition due to the harmonic vibrations > being different than with mags. Know anything about this? > >It is not that they are "not okay to use" but that there are LIMITATIONS on >their use. > >Particularly, the Hartzell Constant Speed props have RPM "do not exceed" >RPMs and "do not dwell long in this zone" RPMs. Basically one must reduce >RPM to under 2700 (say about 2600) after take-off and therre are some >RPM/manifold pressure combinations down lower in the power cover where one >is to avoid continuous operation. In reality these "limitations" are not a >big deal in that they are in areas where you would not likely have the power >set for very long anyway. > >There is a HARD STOP required for the top RPM (I don't remember the exact >number at the moment but say 2750). There's a lot of bits and pieces of fact floating around getting assembled into almost useful information. Let's back off and look at the details. A power delivery system that will convert .25# of fuel into 1 h.p. at the prop tips for one hour is a VERY complex assembly of ideas. No single which they are applied are boundless in number. It's a simple-idea that materials have limitations on ultimate strength as well as service life based on number and amplitude of stress cycles. It's also a simple- (springy) connection can exhibit characteristics of resonance . . . a tuned response to the input of cyclical forces. I got some very lucid and lasting learning experiences the first time I put one of my designs on a shake table and subjected it to 10g of cyclical acceleration over the range of 30 to 2000 Hz. As the shake table's force frequency swept over the test range, there were short intervals of audible and measurable response from within my gizmo. I was told to make note of those frequencies and dwell upon each one for a period of time. This was -IN ADDITION- to the fact that my gizmo was driven with 10g sweeps over the entire range for 15 minutes on each of three orthogonal axes. The first few times I did this test, it wasn't uncommon to find that my gizmo rattled after the test. Opening the can would allow one or more pieces to fall out on the workbench. It took several years before I leaned what NOT to do in order to make my products last through the test. Explorations with accelerometers attached to the test article would often highlight spikes of acceleration levels at resonance for as much as 10 times the exciting force of 10g. Parts that existed happily on the board while subject to ordinary handling readily launched into space when forces equal to 10x the weight of the part were applied many times per second. Piston power plants have many moving parts with all kinds of cyclical forces in terms of dancing pistons, gyrating rocker arms and periods of coasting intermixed with controlled explosions. Most of the airplanes I've flown have no particular concerns over the full range of engine speeds from idle to redline. I think it was the injected 200 hp Lycoming on the Beech Sierra that called for a different color of arc painted over the range of 2000 to 2200 rpm or thereabouts. I was told that there were flyweights on the crank that caused undesirable overstress on a crankshaft over that speed range. One was advised not to dwell in that range while on the way up or down in setting power. When you think about a propeller attached to a crank that runs pistons, it's easy to see possibilities for resonances to exist. The folks who design and sell airplane parts are obligated to explore ALL the possibilities and either eliminate risky combinations or prove that they do not present stresses beyond design limits for the various parts. If you put a certified engine in your airplane with the same propeller that it drove on a production airplane, folks-who-claim-to-know-more-about-airplanes-than- we-do will bless your project after 25 hours of successful flight. Make any changes to that combination and you're expected to sign up for 40 hours of flight. Without instrumentation and carefully crafted tests, even 40 hours of flight may not reveal potential pitfalls created by altering the configuration of a proven design. Putting an electronic ignition on such an engine raises a level of doubt for those who have come to rely on policy and procedure as opposed to experience and common sense. The SAFE thing to do is discourage replacement of mags with electronic ignition systems. This should not be misconstrued as a prohibition but rather a conservative response to not knowing if the change has undesirable effects. Rumors seldom resemble the original intent and concerns after having been run through other individuals for a few years . . . But then, the OBAM aircraft community is where real advances happen every day and experience base grows more swiftly. Electronic ignition never did raise concerns among those who understood engines. I recall discussing it at length with Klaus and several other folks at OSH nearly 20 years ago. One individual who's name I can no longer recall had spent a long and rich career in testing engines of all varieties for everyone from GM and Ford to Briggs and Onan including many designs for aircraft. More than 15 years (and what must by now be millions of flight hours) experience have also laid concerns to rest. If anything, demonstrated smoothness of electronic ignition engines as opposed to their mag-fired brethren suggest that service life of such engines will be enhanced, not compromised. It's a sad commentary on the state of any systems design where operators are cautioned about ranges of operation to be avoided boxed in by ranges that are perfectly acceptable on either side. Red lines should delineate perfectly reasonable boundaries at the edges of a operating envelope. However, warning areas INSIDE the envelope put a very bright spotlight on the inadequacies the design/certification processes. If anyone has a hard data source to share for prohibiting use of electronic ignition on any power plant combination, I'd appreciate knowing about it to the end of disseminating accurate information wherever possible. Bob . . . ________________________________ Message 13 ____________________________________ Time: 01:50:00 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Acronyms --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 03:50 PM 11/23/2003 -0500, you wrote: >--> AeroElectric-List message posted by: > >Hi Bob-- > >At the risk of demonstrating that I'm the only dummy on the list that >doesn't know the score [anyone want to go Snipe hunting?], please explain >what OBAM stands for. I've thought of a couple of possibilities, none of >which make sense or are appropriate for a family setting. Please get me >out of the quandry. I confess, I did it. For years, I've watched the faces of folks reacting to my admission of working with thousands of people building "experimental" airplanes. While this was the official government description for most of what we do, the public perception of the term is unsettling . . . especially when they see how certified aviation is treated in the entertainment industry . . . "experimental" aviation can only be an order of magnitude worse. Check out a copy of "Never Cry Wolf" from the video store. It has an airborne scene that will bust-yer-gut for laughing because you know how absurd the situation is. Problem is that your mother-in-law takes the whole thing very seriously as does the majority of our fellow citizens. In an effort to more accurately describe what has become an industry thriving on tried and proven manufacturing and design concepts, I coined the phrase Owner Built And Maintained as a more accurate way to label our hobby. It's sorta like using words like "contact", "roll" and "collision" to describe a series of events in an accident as opposed to "impact", "spin" and "crash" . . . Juries react very differently to these words. If you have a better term to offer, by all means use it. Similarly, I'll suggest that both internal and external images are much enhanced by eliminating words like "emergency", "essential" and "experimental" from the lexicon of OBAM aircraft speech. Did a Google search and found numerous other phrases defined by OBAM. Also ran across a posting I did many moons ago: > OBAM is the seed of an idea that I thought I'd plant and see what > happens. For years, we've been pretty proud of "amateur built" or > "home built" as terms to describe our craft. Problem is, if you use > these terms in conversation with the average person on the street > you get a response that is less than positive. > > "You mean these airplanes are built in somebody's house?" or > "My gawd, I'd never set foot in an airplane built by an AMATEUR." > > Using the word "experimental" isn't any better. So how about > Owner Built and Maintained aircraft? When amateur built aviation > was in its infancy, each builder was pretty much on his own. Yeah, > there was Sport Aviation and yeah, an occasional mechanic > working in the certified world might drop by to help out . . . > but by-in-large, each completed airplane was a solitary effort. > > Today, with kit offerings joining with a huge and growing > infrastructure of builder communications on the 'Net, I'll suggest > that our efforts are head and shoulders taller than "amateur". > A builder may be working on his first and perhaps only construction > project but the support structure makes his endeavor anything > but amateurish. > > So how about it folks? This is a sort of pull yourself up by the > bootstraps effort. I am reminded of good advice handed down > by many who would mentor somebody up in the knowledge and > skills of their particular specialty. "Son, if you want to be a > _________," then then the FIRST thing you have to do is look, > talk, and act like you ARE a __________." In our case, we > fill in the blanks with the phrase, "builder of the world's > finest single engine airplanes." Bob . . . ________________________________ Message 14 ____________________________________ Time: 02:26:32 PM PST US From: Subject: AeroElectric-List: re OBAM --> AeroElectric-List message posted by: Bob-- Thanks to you and the others that responded. And I certainly agree with your comments. The overall results, the product of the OBAM community speaks for itself. This is where the state of the art, at least in piston aircraft, is being advanced. The next generation should be exciting. Jim ________________________________ Message 15 ____________________________________ Time: 04:36:35 PM PST US From: George Braly Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: George Braly We do crankshaft certifications - - (we are doing one now) on our test stand. Bob, as always, you are invited down to take a look for yourself. From personal face - to- face conversations with people in the OEM prop business, there is a well identified vibration problem with Lycoming 4 cylinder engines and electronic ignition systems. The same problem does not exist with magnetos. From the OEM prop people's first hand comments and from the data we see with strain gages mounted up on crank shafts during certification tests, for the purpose of determining the power combinations at which peak torsional stresses happen, I believe that the concern about the electronic ignition (as it is typically implemented) is legitimate. This judgment on my part is reached based on both observation of the data and the underlying theory. Regards, George PS. I confirm your electronic parts - rattle around in the can - scenario!!! We have our own shake table - - and it is amazing to see what comes loose and why and at what frequency! -----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: Magneto Relpacements --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > I've heard that some props are not okay to use > with electronic ignition due to the harmonic vibrations > being different than with mags. Know anything about this? > >It is not that they are "not okay to use" but that there are LIMITATIONS on >their use. > >Particularly, the Hartzell Constant Speed props have RPM "do not exceed" >RPMs and "do not dwell long in this zone" RPMs. Basically one must reduce >RPM to under 2700 (say about 2600) after take-off and therre are some >RPM/manifold pressure combinations down lower in the power cover where one >is to avoid continuous operation. In reality these "limitations" are not a >big deal in that they are in areas where you would not likely have the power >set for very long anyway. > >There is a HARD STOP required for the top RPM (I don't remember the exact >number at the moment but say 2750). There's a lot of bits and pieces of fact floating around getting assembled into almost useful information. Let's back off and look at the details. A power delivery system that will convert .25# of fuel into 1 h.p. at the prop tips for one hour is a VERY complex assembly of ideas. No single which they are applied are boundless in number. It's a simple-idea that materials have limitations on ultimate strength as well as service life based on number and amplitude of stress cycles. It's also a simple- (springy) connection can exhibit characteristics of resonance . . . a tuned response to the input of cyclical forces. I got some very lucid and lasting learning experiences the first time I put one of my designs on a shake table and subjected it to 10g of cyclical acceleration over the range of 30 to 2000 Hz. As the shake table's force frequency swept over the test range, there were short intervals of audible and measurable response from within my gizmo. I was told to make note of those frequencies and dwell upon each one for a period of time. This was -IN ADDITION- to the fact that my gizmo was driven with 10g sweeps over the entire range for 15 minutes on each of three orthogonal axes. The first few times I did this test, it wasn't uncommon to find that my gizmo rattled after the test. Opening the can would allow one or more pieces to fall out on the workbench. It took several years before I leaned what NOT to do in order to make my products last through the test. Explorations with accelerometers attached to the test article would often highlight spikes of acceleration levels at resonance for as much as 10 times the exciting force of 10g. Parts that existed happily on the board while subject to ordinary handling readily launched into space when forces equal to 10x the weight of the part were applied many times per second. Piston power plants have many moving parts with all kinds of cyclical forces in terms of dancing pistons, gyrating rocker arms and periods of coasting intermixed with controlled explosions. Most of the airplanes I've flown have no particular concerns over the full range of engine speeds from idle to redline. I think it was the injected 200 hp Lycoming on the Beech Sierra that called for a different color of arc painted over the range of 2000 to 2200 rpm or thereabouts. I was told that there were flyweights on the crank that caused undesirable overstress on a crankshaft over that speed range. One was advised not to dwell in that range while on the way up or down in setting power. When you think about a propeller attached to a crank that runs pistons, it's easy to see possibilities for resonances to exist. The folks who design and sell airplane parts are obligated to explore ALL the possibilities and either eliminate risky combinations or prove that they do not present stresses beyond design limits for the various parts. If you put a certified engine in your airplane with the same propeller that it drove on a production airplane, folks-who-claim-to-know-more-about-airplanes-than- we-do will bless your project after 25 hours of successful flight. Make any changes to that combination and you're expected to sign up for 40 hours of flight. Without instrumentation and carefully crafted tests, even 40 hours of flight may not reveal potential pitfalls created by altering the configuration of a proven design. Putting an electronic ignition on such an engine raises a level of doubt for those who have come to rely on policy and procedure as opposed to experience and common sense. The SAFE thing to do is discourage replacement of mags with electronic ignition systems. This should not be misconstrued as a prohibition but rather a conservative response to not knowing if the change has undesirable effects. Rumors seldom resemble the original intent and concerns after having been run through other individuals for a few years . . . But then, the OBAM aircraft community is where real advances happen every day and experience base grows more swiftly. Electronic ignition never did raise concerns among those who understood engines. I recall discussing it at length with Klaus and several other folks at OSH nearly 20 years ago. One individual who's name I can no longer recall had spent a long and rich career in testing engines of all varieties for everyone from GM and Ford to Briggs and Onan including many designs for aircraft. More than 15 years (and what must by now be millions of flight hours) experience have also laid concerns to rest. If anything, demonstrated smoothness of electronic ignition engines as opposed to their mag-fired brethren suggest that service life of such engines will be enhanced, not compromised. It's a sad commentary on the state of any systems design where operators are cautioned about ranges of operation to be avoided boxed in by ranges that are perfectly acceptable on either side. Red lines should delineate perfectly reasonable boundaries at the edges of a operating envelope. However, warning areas INSIDE the envelope put a very bright spotlight on the inadequacies the design/certification processes. If anyone has a hard data source to share for prohibiting use of electronic ignition on any power plant combination, I'd appreciate knowing about it to the end of disseminating accurate information wherever possible. Bob . . . --- Incoming mail is certified Virus Free. --- ________________________________ Message 16 ____________________________________ Time: 04:51:22 PM PST US From: Jim Sower Subject: Re: AeroElectric-List: EI and Prop Vib was: Magneto Replacement --> AeroElectric-List message posted by: Jim Sower <... prop people seem to be scrambling to limit their liability exposure ...> That pretty much says it all. That many disclaimers didn't sound like an engineering decision. I'll still have to stay away from Hartzell, but that's no great loss anyway. ________________________________ Message 17 ____________________________________ Time: 06:01:59 PM PST US From: Subject: AeroElectric-List: re Electronic Ignition --> AeroElectric-List message posted by: George-- In your own testing or in talking to OEMs, have you seen or heard of the same problem with 6 cyl engines as you report for 4 cyl. I'm interested in Lyc in particular. In any case, it seems to me that Hartzel, and perhaps others, have taken a PYA stance rather than test, confirm, identify and quantify a potential problem. They want to sell props to the independents like us, but have apparently not done their homework and informed us of verifiable data. They have simply passed on their questions to us. Not acceptable. Jim ________________________________ Message 18 ____________________________________ Time: 07:01:21 PM PST US From: George Braly Subject: RE: AeroElectric-List: re Electronic Ignition --> AeroElectric-List message posted by: George Braly Jim, On the contrary - - they HAVE done the tests. They have the data. They didn't dream this up. They were as surprised by the results as everybody else. Don't blame the messenger on this one. In fact, give them credit for having the presence of mind to take note of the issue when it arose. I do not know if the same issue exists with the 6 cylinder engines. But, the theory behind the "why" of this issue is the same with either 6, 4, or 8 cylinder engines. OTOH, as has been pointed out, these are such complex vibration systems that making predictions is not a reliable way to approach the issue. Regards, George -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of jimk36@comcast.net Subject: AeroElectric-List: re Electronic Ignition --> AeroElectric-List message posted by: George-- In your own testing or in talking to OEMs, have you seen or heard of the same problem with 6 cyl engines as you report for 4 cyl. I'm interested in Lyc in particular. In any case, it seems to me that Hartzel, and perhaps others, have taken a PYA stance rather than test, confirm, identify and quantify a potential problem. They want to sell props to the independents like us, but have apparently not done their homework and informed us of verifiable data. They have simply passed on their questions to us. Not acceptable. Jim --- Incoming mail is certified Virus Free. --- ________________________________ Message 19 ____________________________________ Time: 07:13:56 PM PST US From: Jim Sower Subject: Re: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: Jim Sower <... from the data we see with strain gages mounted up on crank shafts during certification tests ... the concern about the electronic ignition ... is legitimate ...> I am amazed and chagrined. It is incredible to me that something that makes the engine run so much smoother could cause/aggravate damaging vibration/harmonics. I asked for credible evidence and I got it. I stand corrected ... Jim S. George Braly wrote: > --> AeroElectric-List message posted by: George Braly > > We do crankshaft certifications - - (we are doing one now) on our test > stand. > > Bob, as always, you are invited down to take a look for yourself. > > >From personal face - to- face conversations with people in the OEM prop > business, there is a well identified vibration problem with Lycoming 4 > cylinder engines and electronic ignition systems. The same problem does not > exist with magnetos. > > >From the OEM prop people's first hand comments and from the data we see with > strain gages mounted up on crank shafts during certification tests, for the > purpose of determining the power combinations at which peak torsional > stresses happen, I believe that the concern about the electronic ignition > (as it is typically implemented) is legitimate. > > This judgment on my part is reached based on both observation of the data > and the underlying theory. ________________________________ Message 20 ____________________________________ Time: 07:33:10 PM PST US From: "Dan Branstrom" Subject: Re: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "Dan Branstrom" The solution? Wood props. ; ) Do not archive Dan Branstrom ----- Original Message ----- From: "Jim Sower" Subject: Re: AeroElectric-List: Magneto Relpacements > --> AeroElectric-List message posted by: Jim Sower > > <... from the data we see with strain gages mounted up on crank shafts during > certification tests ... the concern about the electronic ignition ... is > legitimate ...> > I am amazed and chagrined. It is incredible to me that something that makes the > engine run so much smoother could cause/aggravate damaging vibration/harmonics. > I asked for credible evidence and I got it. > I stand corrected ... Jim S. > > > George Braly wrote: > > > --> AeroElectric-List message posted by: George Braly > > > > We do crankshaft certifications - - (we are doing one now) on our test > > stand. > > > > Bob, as always, you are invited down to take a look for yourself. > > > > >From personal face - to- face conversations with people in the OEM prop > > business, there is a well identified vibration problem with Lycoming 4 > > cylinder engines and electronic ignition systems. The same problem does not > > exist with magnetos. > > > > >From the OEM prop people's first hand comments and from the data we see with > > strain gages mounted up on crank shafts during certification tests, for the > > purpose of determining the power combinations at which peak torsional > > stresses happen, I believe that the concern about the electronic ignition > > (as it is typically implemented) is legitimate. > > > > This judgment on my part is reached based on both observation of the data > > and the underlying theory. > > ________________________________ Message 21 ____________________________________ Time: 07:41:06 PM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "James E. Clark" Jim, There is a simple answer to your question. Call Hartzell or Sensenich. I suspect they have PLENTY of engineering data on this. This is not some bogus game being played. But ... if you are willing to fly YOUR Hartzell/O-360/EI at 2900 RPM due to a lack of adequate data, go right ahead. It is your plane/prop/life. :-) By the way, I do plan to have an O-360 with Lightspeed EI and a Hartzell C/S prop on my RV. And I plan to honor the "limitations" that they have (in my mind) clearly expressed. Comments below. James > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Jim > Sower > Sent: Sunday, November 23, 2003 11:15 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Magneto Relpacements > > > --> AeroElectric-List message posted by: Jim Sower > > > <... have RPM "do not exceed" RPMs and "do not dwell long in this > zone" RPMs ... HARD > STOP required for the top RPM ...> > What do these have to do with EI? You are closer to multiples of the disaster frequencies that result from the pulse of the engine WITH the EI. > > <... The logic (simply put) is that the pulses you get using EI > cause a DIFFERENT burn > and thus a different "ping" on the engine (probably a sharper > bigger bang (??) and thus > the improvement in performance) ...> > This statement is based on ... what?? Engineering research or > brain fart? Or what? > ***SIGNIFICANT*** engineering research. NOT by me but by the PROP MANUFACTURERS!! Don't take ANYBODY's word for it from this list (especially not mine :-) )... call the prop makers ... Hartzell and Sensenich. {Better yet, CALL THEIR COMPETITION) > <... (probably a sharper bigger bang (??) ...> > I know that EI provides MUCH more optimum spark timing for rpm > than mags (around 35-40 > deg as compared with mags which are bolted on at 25 deg or so) > and that CD is a much > higher quality and more reliable spark (and therefore better > flame front) than mags > produce. Advanced timing starts combustion early enough that you > get full benefit of > the power stroke and don't dump still-trying-to-work combustion > gasses over the side > (think improved fuel efficiency and exhaust valve life). > > <... Hit the right harmonic ON ANYTHING and it shakes apart!! ...> > Agreed. Harmonics can be devastating. That said, what is the > credible (key word here) > evidence that replacing 1930s technology mags with a device that > provides much higher > quality ignition at optimum timing is going to cause these > harmonics? No offense, but > I'm going to need specific documentation on this one. Call HARTZELL or SENSENICH. They will probably give you loads of information. Although if I were them, I would not give you (or anyone) proprietary data that could be abused buy the "competition". > > I'm reluctant to get real shrill absent credible engineering to > back up the rumors ... > Jim S. Do you think no credible engineering is behind these prop manufactures' STRONG LIMITAIONS? Clearly they are not putting these notices out to sell MORE props. They are doing it so we don't go run our engines in regions where the KNOW there *COULD* be a potential problem. When Van's Aircraft says if you pull more than 9-10 G's you wings will break off so stay below +6 and -3, I don't really care to see all of their engineering data and I plan to stay way below the +6/-3Gs. When H & S say that bad things will happen to THEIR props if you run them at certain RPMs on Lycoming engines with electronic ignition, I (maybe naively so) believe that they have done some engineering to make the claim. Actually, I think they will actually tell you what the "magic" frequency is. I seem to have heard it somewhere but will not guess it here in this forum. I will leave that to them to say as they choose. James > > ________________________________ Message 22 ____________________________________ Time: 08:06:51 PM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "James E. Clark" > > If anyone has a hard data source to share for > prohibiting use of electronic ignition on any > power plant combination, I'd appreciate knowing > about it to the end of disseminating accurate > information wherever possible. > > Bob . . . > Bob, This may be nitpicking but I don't think they are "prohibiting" the use of EI. I have never heard that either Sensenich or Hartzell prohibits the use of their props with EI etc. Instead it seems they are saying (for WHATEVER reason) "we have problems on *these* engines, with *these* mods, in *these* RPM ranges, using *these* props of ours". There was a LOT of stuff posted some time ago about the strain gauges and accelerometers that Sensenich (I believe) put on one of their props that was on an RV6 (A?). They eventually came up with a design that did not have the limitations for the O-360 but the one for the O-320 did (does still?) have the limitations. I for one, called Hartzell and chatted with them. I even spoke to their CEO and their engineers. They looked into this stuff and generated real data. They even did work to redesign the prop. The new model has slightly less limitations. They simply have NOT come up with a design yet that has the "comfort zone" they wish at all relevant RPMs on the engine setups of interest and thus the "warnings". Seems to me the are doing exactly what we would want them to do. Again, in real world flying, I don't think anyone is feeling really cramped by the "limitations". James ________________________________ Message 23 ____________________________________ Time: 08:11:17 PM PST US From: George Braly Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: George Braly Having done a crankshaft torsional vibration test on a 4 cylinder lycoming - - including sweeps up to 3000 RPM - - Let me strongly suggest that you do NOT operate these engines past 2700 RPM for other than momentary overspeed reasons. Regardless of the prop. This is a crankshaft and accessory case issue. I can (and did - - over and over again for 150 hours) fail the typical slick magneto in about an average of 15 to 20 hours - - when operating this engine at ~2900 RPM. Regards, George -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of James E. Clark Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: "James E. Clark" Jim, There is a simple answer to your question. Call Hartzell or Sensenich. I suspect they have PLENTY of engineering data on this. This is not some bogus game being played. But ... if you are willing to fly YOUR Hartzell/O-360/EI at 2900 RPM due to a lack of adequate data, go right ahead. It is your plane/prop/life. :-) By the way, I do plan to have an O-360 with Lightspeed EI and a Hartzell C/S prop on my RV. And I plan to honor the "limitations" that they have (in my mind) clearly expressed. Comments below. James > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com]On Behalf Of Jim > Sower > Sent: Sunday, November 23, 2003 11:15 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Magneto Relpacements > > > --> AeroElectric-List message posted by: Jim Sower > > > <... have RPM "do not exceed" RPMs and "do not dwell long in this > zone" RPMs ... HARD > STOP required for the top RPM ...> > What do these have to do with EI? You are closer to multiples of the disaster frequencies that result from the pulse of the engine WITH the EI. > > <... The logic (simply put) is that the pulses you get using EI > cause a DIFFERENT burn > and thus a different "ping" on the engine (probably a sharper > bigger bang (??) and thus > the improvement in performance) ...> > This statement is based on ... what?? Engineering research or > brain fart? Or what? > ***SIGNIFICANT*** engineering research. NOT by me but by the PROP MANUFACTURERS!! Don't take ANYBODY's word for it from this list (especially not mine :-) )... call the prop makers ... Hartzell and Sensenich. {Better yet, CALL THEIR COMPETITION) > <... (probably a sharper bigger bang (??) ...> > I know that EI provides MUCH more optimum spark timing for rpm > than mags (around 35-40 > deg as compared with mags which are bolted on at 25 deg or so) > and that CD is a much > higher quality and more reliable spark (and therefore better > flame front) than mags > produce. Advanced timing starts combustion early enough that you > get full benefit of > the power stroke and don't dump still-trying-to-work combustion > gasses over the side > (think improved fuel efficiency and exhaust valve life). > > <... Hit the right harmonic ON ANYTHING and it shakes apart!! ...> > Agreed. Harmonics can be devastating. That said, what is the > credible (key word here) > evidence that replacing 1930s technology mags with a device that > provides much higher > quality ignition at optimum timing is going to cause these > harmonics? No offense, but > I'm going to need specific documentation on this one. Call HARTZELL or SENSENICH. They will probably give you loads of information. Although if I were them, I would not give you (or anyone) proprietary data that could be abused buy the "competition". > > I'm reluctant to get real shrill absent credible engineering to > back up the rumors ... > Jim S. Do you think no credible engineering is behind these prop manufactures' STRONG LIMITAIONS? Clearly they are not putting these notices out to sell MORE props. They are doing it so we don't go run our engines in regions where the KNOW there *COULD* be a potential problem. When Van's Aircraft says if you pull more than 9-10 G's you wings will break off so stay below +6 and -3, I don't really care to see all of their engineering data and I plan to stay way below the +6/-3Gs. When H & S say that bad things will happen to THEIR props if you run them at certain RPMs on Lycoming engines with electronic ignition, I (maybe naively so) believe that they have done some engineering to make the claim. Actually, I think they will actually tell you what the "magic" frequency is. I seem to have heard it somewhere but will not guess it here in this forum. I will leave that to them to say as they choose. James > > --- Incoming mail is certified Virus Free. --- ________________________________ Message 24 ____________________________________ Time: 08:16:57 PM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: EI and Prop Vib was: Magneto Replacement --> AeroElectric-List message posted by: "James E. Clark" Jim, This is NOT the case! There is ENGINEERING behind these comments. Again, call Hartzell or Sensenich and they will fill you in. If you plan to use some other fine prop, then that is cool. Hartzell may very well NOT be the right prop for your airplane's mission profile. I was happily flying behind an Ed Sterba wood prop today and I HAVE been over 2700 RPM with it (using EI). I and others will also happily fly behind a Hartzell or Sensenich. Let's not go and blast a company on such a public forum before we have asked them directly on such an important matter. James ... a person that DID call Hartzell and DID get an answer. > > <... prop people seem to be scrambling to limit their liability > exposure ...> > That pretty much says it all. That many disclaimers didn't sound > like an engineering decision. I'll still have to stay away from > Hartzell, but that's no great loss anyway. > > > > ________________________________ Message 25 ____________________________________ Time: 08:34:20 PM PST US From: "Rick Fogerson" Subject: Re: AeroElectric-List: Bob, need info on microair com/xpdr --> AeroElectric-List message posted by: "Rick Fogerson" Do Not Archive I did not receive an operations manual with the MicroAir T2000 xpdr. Does anyone know if one is available on the internet or if a hard copy is available from someone. Thanks, Rick Fogerson RV3 wiring Boise, ID ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Bob, need info on microair com/xpdr > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > At 05:10 PM 11/17/2003 -0700, you wrote: > >--> AeroElectric-List message posted by: "Rick Fogerson" > > > >Hi Bob, > >I bought wiring harnesses from you some time back but just getting around > >to installing. I'm building an RV3 so no need for intercom or co-pilot > >stuff. No wiring diagram sent so I need to know what they connect to. > > Blue jacket shielded wire is reply beep out that can optionally be > routed to your audio distribution amplifier. I'm not sure as to the > exact function of this feature, manual should be more helpful. > > ================= > > ________________________________ Message 26 ____________________________________ Time: 08:47:34 PM PST US From: "James E. Clark" Subject: RE: AeroElectric-List: re Electronic Ignition --> AeroElectric-List message posted by: "James E. Clark" Jim, I know your comment was to George, but **NO** this is **NOT** what they are doing. This is an important matter and seems to me they have acted VERY responsibly!! They HAVE done engineering, they DID discover this as a result and they DID inform us. Next they HAVE tried (with varied success) to come up with NEW designs to "fix the problem". I would bet they are STILL working on the matter. Again, they are NOT asking us to solve THEIR problem. Now **I** would have been upset if they knew about this and did NOT tell us nor try to improve the design for fear that we would not buy their products. At OSH this year, I also spent quite a bit of time with SEVERAL prop manufacturers ... including the "competition" for Hartzell. I have even spent a bit of time talking to the people at Van's on this. I plan to go Hartzell. My point here is that there is LOTS of info available for the asking and plenty on the Van's website for instance on this matter. Let's not so quickly "dog" the "good guys". James p.s. I have been commenting on this matter so much because a) I think it IS important **and** b) I do not wish to see a potential bashing of what I think is a fine company trying to "so the right thing" with a tough problem. Especially in the case where it seems the opinions are being formed yet they have not been contacted DIRECTLY on such an important matter. I have **NO** business or otherwise connections to **ANY** prop manufacturer beyond my intentions to use a HArtzell and being a current customer of Ed Sterba. > > George-- > > > In any case, it seems to me that Hartzel, and perhaps others, > have taken a PYA stance rather than test, confirm, identify and > quantify a potential problem. They want to sell props to the > independents like us, but have apparently not done their homework > and informed us of verifiable data. They have simply passed on > their questions to us. Not acceptable. > > Jim > > ________________________________ Message 27 ____________________________________ Time: 09:47:41 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Bob, need info on microair com/xpdr --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:36 PM 11/23/2003 -0700, you wrote: >--> AeroElectric-List message posted by: "Rick Fogerson" > >Do Not Archive > >I did not receive an operations manual with the MicroAir T2000 xpdr. Does >anyone know if one is available on the internet or if a hard copy is >available from someone. >Thanks, Rick Fogerson >RV3 wiring >Boise, ID Did you get this radio from me? There's supposed to be a copy of installation and operating instructions in each shipment. You can download the POH at: http://www.microair.com.au//admin/uploads/T2000_user_manual_V27.pdf or if you have trouble with that link try my server at: http://www.aeroelectric.com/Installation_Data/T2000_user_manual_V27.pdf Bob . . . ________________________________ Message 28 ____________________________________ Time: 09:47:41 PM PST US From: "Greg Milner" Subject: AeroElectric-List: Odyssey battery --> AeroElectric-List message posted by: "Greg Milner" I`m using a dry cell Odyssey 680 battery as was recommended by an EAA T.C. who`s been using one. It`s small and kicks the engine over well. sunbattery.com is the supplier.They won`t freeze and last long time. ________________________________ Message 29 ____________________________________ Time: 10:24:03 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Odyssey battery --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 11:46 PM 11/23/2003 -0600, you wrote: >--> AeroElectric-List message posted by: "Greg Milner" > >I`m using a dry cell Odyssey 680 battery as was recommended by an EAA T.C. >who`s been using one. It`s small and kicks the engine over well. >sunbattery.com is the supplier.They won`t freeze and last long time. This is not a "dry" battery . . . but it is an excellent example of a recombinant gas and/or sealed lead acid battery. However, if discharged completely, it will freeze just like any other lead-acid battery. Given the very low water content in the almost- saturated glass mats, it may not be damaging. I'll have to check with the manufacturers on this. It shouldn't be a big issue since this battery, like all others of the type, have a very low self-discharge rate and should store nicely over the winter without special maintenance and without becoming susceptible to freezing. Bob . . . ________________________________ Message 30 ____________________________________ Time: 10:47:42 PM PST US From: George Braly Subject: RE: AeroElectric-List: Magneto Relpacements --> AeroElectric-List message posted by: George Braly <... from the data we see with strain gages mounted up on crank shafts during certification tests ... the concern about the electronic ignition ... is legitimate ...> I am amazed and chagrined. It is incredible to me that something that makes the engine run so much smoother could cause/aggravate damaging vibration/harmonics. I asked for credible evidence and I got it. I stand corrected ... Jim S. Think of the troops doing double time across the wooden bridge. If they all trot along in pure cadence - - ah... it sounds so smooth. Of course, if the cadence happens to be near the resonant frequency of the bridge - - Regards, George PS. Sometimes the enemy of good is a misguided attempt at better! ---