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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
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
<<<SNIP>>>
> 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
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| Subject: | Re: RG Battery source |
--> AeroElectric-List message posted by: "LarryRobertHelming" <lhelming@sigecom.net>
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" <dave@davemorris.com>
Subject: AeroElectric-List: RG Battery source
> --> AeroElectric-List message posted by: Dave Morris <dave@davemorris.com>
>
> 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
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 10:52 PM 11/22/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: Dave Morris <dave@davemorris.com>
>
>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
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| Subject: | Re: Magneto Relpacements |
--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
<... 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" <james@nextupventures.com>
>
> 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
>
> <<<SNIP>>>
> > 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
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| Subject: | Re: Magneto Relpacements |
--> AeroElectric-List message posted by: Tom Caruthers <tomcaruthers@yahoo.com>
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 <canarder@frontiernet.net> wrote:
> --> AeroElectric-List message posted by: Jim Sower
> <canarder@frontiernet.net>
>
> <... 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" <james@nextupventures.com>
> >
> > 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
> >
> > <<<SNIP>>>
> > > 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
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>
>
>
>
>
__________________________________
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Message 6
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| Subject: | Re: Magneto Relpacements |
--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
<... 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
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| Subject: | EI and Prop Vib was: Magneto Replacement |
--> AeroElectric-List message posted by: "Treff, Arthur" <Arthur.Treff@Smartm.com>
<... 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
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--> AeroElectric-List message posted by: <jimk36@comcast.net>
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
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--> AeroElectric-List message posted by: "David Swartzendruber" <dswartzendruber@earthlink.net>
OBAM is Owner Built And Maintained.
do not archive
>
> please explain what OBAM stands for.
> Jim
Message 10
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--> AeroElectric-List message posted by: "Ageless Wings" <harley@agelesswings.com>
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: <jimk36@comcast.net>
>>
>> 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
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--> AeroElectric-List message posted by: "Neville Kilford" <nkilford@etravel.org>
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: <jimk36@comcast.net>
Subject: AeroElectric-List: Acronyms
> --> AeroElectric-List message posted by: <jimk36@comcast.net>
>
> 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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
> 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).
<snip>
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
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--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 03:50 PM 11/23/2003 -0500, you wrote:
>--> AeroElectric-List message posted by: <jimk36@comcast.net>
>
>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
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--> AeroElectric-List message posted by: <jimk36@comcast.net>
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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: George Braly <gwbraly@gami.com>
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"
<bob.nuckolls@cox.net>
> 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).
<snip>
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
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| Subject: | Re: EI and Prop Vib was: Magneto Replacement |
--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
<... 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
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| Subject: | re Electronic Ignition |
--> AeroElectric-List message posted by: <jimk36@comcast.net>
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
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| Subject: | re Electronic Ignition |
--> AeroElectric-List message posted by: George Braly <gwbraly@gami.com>
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: <jimk36@comcast.net>
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
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| Subject: | Re: Magneto Relpacements |
--> AeroElectric-List message posted by: Jim Sower <canarder@frontiernet.net>
<... 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 <gwbraly@gami.com>
>
> 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
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| Subject: | Re: Magneto Relpacements |
--> AeroElectric-List message posted by: "Dan Branstrom" <danbranstrom@verizon.net>
The solution? Wood props. ;
)
Do not archive
Dan Branstrom
----- Original Message -----
From: "Jim Sower" <canarder@frontiernet.net>
Subject: Re: AeroElectric-List: Magneto Relpacements
> --> AeroElectric-List message posted by: Jim Sower
<canarder@frontiernet.net>
>
> <... 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 <gwbraly@gami.com>
> >
> > 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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
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
> <canarder@frontiernet.net>
>
> <... 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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
>
> 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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: George Braly <gwbraly@gami.com>
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"
<james@nextupventures.com>
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
> <canarder@frontiernet.net>
>
> <... 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
>
>
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Message 24
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| Subject: | EI and Prop Vib was: Magneto Replacement |
--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
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
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| Subject: | Re: Bob, need info on microair com/xpdr |
--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
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" <bob.nuckolls@cox.net>
Subject: Re: AeroElectric-List: Bob, need info on microair com/xpdr
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
<bob.nuckolls@cox.net>
>
> At 05:10 PM 11/17/2003 -0700, you wrote:
> >--> AeroElectric-List message posted by: "Rick Fogerson"
<rickf@cableone.net>
> >
> >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
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| Subject: | re Electronic Ignition |
--> AeroElectric-List message posted by: "James E. Clark" <james@nextupventures.com>
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.
<SNIP>
>
> George--
>
<SNIP>
>
> 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
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| Subject: | Re: Bob, need info on microair com/xpdr |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 09:36 PM 11/23/2003 -0700, you wrote:
>--> AeroElectric-List message posted by: "Rick Fogerson" <rickf@cableone.net>
>
>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
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--> AeroElectric-List message posted by: "Greg Milner" <tldrgred@execpc.com>
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
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| Subject: | Re: Odyssey battery |
--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" <bob.nuckolls@cox.net>
At 11:46 PM 11/23/2003 -0600, you wrote:
>--> AeroElectric-List message posted by: "Greg Milner" <tldrgred@execpc.com>
>
>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
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| Subject: | Magneto Relpacements |
--> AeroElectric-List message posted by: George Braly <gwbraly@gami.com>
<... 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!
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