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:


In a message dated 5/12/2005 10:21:35 A.M. Central Standard Time, walter@advancedpilot.com writes:

As it turns out, this is a major effect.  You must quantify how rich
and how lean for the second statement to be accurate.  There are some
rich mixtures that burn slower than some lean mixtures.  As a matter of
fact, 40dF ROP is the fastest burn rate mixture.

The charts you posted are true for a given mixture.  As the mixture
changes, the chart values would change.  Mixture has a major effect on
the effective timing...  which is the only thing we really care about.

Walter,
 
Yeah, well I remember a GAMI chart that shows a broad range of timing with little or no effect on destruction.  I don't have any problem with self-controlling the last knob (mixture) in 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 to arrive at some non-destructive highest and best power setting for the extant environmental and operating conditions.  All I have to do is figure out what "is" is.  Maybe I need a theta-beta-zeta cylinder wall distortion sensor.
 
OK, 40F ROP is the fastest burn rate.  What is a non-destructive LOP slower rate and what is the timing spread contribution (even a rule of thumb would do) -- or do I have to deduce this by myself in the "flight experimental" mode?  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.
 
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 performance.  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.
 
I guess I am going to try things at ROP first - then LOP over a string of airports.
 
I like this stuff, it tears at my orderly life.
 
 
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 to the anchor.
In aviation, as in life, nothing fixes itself.
There ain't no tow truck when you are positive AGL.