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From: Walter Atkinson <walter@advancedpilot.com>
Subject: Re: [LML] Re: Electronic Ignition Timing Charts


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Scott:

Since the issue where destruction is concerned is the peak pressure,=20
why not just MEASURE that rather than use a batch of sensors to=20
calculate it?

If you also measure thetaPP, you have all of the information you need=20
to get max torque AND stay under the destruction point.

Walter


On May 12, 2005, at 8:18 PM, Sky2high@aol.com wrote:


In a message dated 5/12/2005 10:21:35 A.M. Central Standard Time,=20
walter@advancedpilot.com writes:
> As it turns out, this is a major effect.=A0 You must quantify how rich
> and how lean for the second statement to be accurate.=A0 There are =
some
> rich mixtures that burn slower than some lean mixtures.=A0 As a matter =
of
> fact, 40dF ROP is the fastest burn rate mixture.
>
> The charts you posted are true for a given mixture.=A0 As the mixture
> changes, the chart values would change.=A0 Mixture has a major effect =
on
> the effective timing...=A0 which is the only thing we really care =
about.
Walter,
=A0
Yeah, well I remember a GAMI chart that shows a broad range of timing=20
with little or no effect on destruction.=A0 I don't have any problem =
with=20
self-controlling the last knob (mixture)=A0in the "best power" combo=20
although I would prefer some useful info from something like an exhaust=20=

O2 sensor, mass airflow sensor, temperature sensor - all helping with=20
data=A0to arrive at some non-destructive highest and best=A0power =
setting=20
for the extant=A0environmental and operating conditions.=A0 All I have =
to=20
do is figure out what "is" is.=A0 Maybe I need a theta-beta-zeta =
cylinder=20
wall distortion sensor.
=A0
OK, 40F ROP is the fastest burn rate.=A0 What is a non-destructive LOP=20=

slower rate and what is the timing spread contribution (even a rule of=20=

thumb would do)=A0-- or do I have to deduce this by myself in the =
"flight=20
experimental" mode?=A0 Half the EI folk don't want to reveal the timing=20=

curves while, at least in one case, with enough work one can discover=20
it.
=A0
BTW, Some of us are still waiting for something like a real FADEC,=20
PRISM, EPIC, OPUS, ERATO, CROSSWORD PUZZLE or whatever - - (kinda like=20=

a useful diesel), but they never seem to quite arrive and deliver the=20
desired=A0performance.=A0 Of course, one would expect these things to be=20=

developed in the "experimental" field before someone tries to jam=20
another fix-up on a Bonanza.
=A0
I guess I am going to try things at ROP first - then LOP over a string=20=

of airports.
=A0
I like this stuff, it tears at my orderly life.
=A0
=A0
Scott Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

Training is no substitute for fear,risk analysis and judgement.
Recognize the links in the chain of errors before the last link joins=20
to the anchor.
In aviation, as in life, nothing fixes itself.
There ain't no tow truck when you are positive AGL.


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Scott:


Since the issue where destruction is concerned is the peak pressure,
why not just MEASURE that rather than use a batch of sensors to
calculate it?


If you also measure thetaPP, you have all of the information you need
to get max torque AND stay under the destruction point.


Walter


On May 12, 2005, at 8:18 PM, Sky2high@aol.com wrote:


<fontfamily><param>Arial</param><smaller>In a message dated 5/12/2005
10:21:35 A.M. Central Standard Time, walter@advancedpilot.com =
writes:</smaller></fontfamily>

<excerpt><fontfamily><param>Arial</param><smaller>As it turns out,
this is a major effect.=A0 You must quantify how =
rich</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>and how lean for the second
statement to be accurate.=A0 There are some</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>rich mixtures that burn
slower than some lean mixtures.=A0 As a matter of =
</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>fact, 40dF ROP is the fastest
burn rate mixture.</smaller></fontfamily>


<fontfamily><param>Arial</param><smaller>The charts you posted are
true for a given mixture.=A0 As the mixture</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>changes, the chart values
would change.=A0 Mixture has a major effect on </smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>the effective timing...=A0
which is the only thing we really care about.</smaller></fontfamily>

=
</excerpt><fontfamily><param>Arial</param><smaller>Walter,</smaller></font=
family>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Yeah, well I remember a GAMI
chart that shows a broad range of timing with little or no effect on
destruction.=A0 I don't have any problem with self-controlling the last
knob (mixture)=A0in the "best power" combo although I would prefer some
useful info from something like an exhaust O2 sensor, mass airflow
sensor, temperature sensor - all helping with data=A0to arrive at some
non-destructive highest and best=A0power setting for the
extant=A0environmental and operating conditions.=A0 All I have to do is
figure out what "is" is.=A0 Maybe I need a theta-beta-zeta cylinder wall
distortion sensor.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>OK, 40F ROP is the fastest
burn rate.=A0 What is a non-destructive LOP slower rate and what is the
timing spread contribution (even a rule of thumb would do)=A0-- or do I
have to deduce this by myself in the "flight experimental" mode?=A0 Half
the EI folk don't want to reveal the timing curves while, at least in
one case, with enough work one can discover it.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>BTW, Some of us are still
waiting for something like a real FADEC, PRISM, EPIC, OPUS, ERATO,
CROSSWORD PUZZLE or whatever - - (kinda like a useful diesel), but
they never seem to quite arrive and deliver the desired=A0performance.=A0
Of course, one would expect these things to be developed in the
"experimental" field before someone tries to jam another fix-up on a
Bonanza.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>I guess I am going to try
things at ROP first - then LOP over a string of =
airports.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>I like this stuff, it tears
at my orderly life.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>=A0</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Scott Krueger AKA =
Grayhawk</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Lancair N92EX IO320 SB =
89/96</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Aurora, IL =
(KARR)</smaller></fontfamily>


<fontfamily><param>Arial</param><smaller>Training is no substitute for
fear,risk analysis and judgement.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>Recognize the links in the
chain of errors before the last link joins to the =
anchor.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>In aviation, as in life,
nothing fixes itself.</smaller></fontfamily>

<fontfamily><param>Arial</param><smaller>There ain't no tow truck when
you are positive AGL.</smaller></fontfamily>


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