Yes see my previous message. I fixed that problem above.
Scenario: Pilot forgets to change the mixture.
Start Operation. Power ...... Fuel Air...... Mixture .. EGT
---------------------------------------------------------------
LOP ..climb .... Reducing ....Same decreasing leaner lower
LOP ..descend .. Increasing ..Same increasing richer higher
ROP ..climb .... Reducing ....Same decreasing leaner maybe the same due to reduced power.
ROP ..descend .. increasing ..Same increasing Richer lower
The combination of increased power with richer mixture and higher EGT
while descending is the valve killer while operating lean of peak.
Paul Lamar
Paul, I think I must be missing something in this discussion. If you lean at altitude to max EGT and then continue lean-of-peak the egt drops. If you decend into more oxygen rich air at lower
altitude your mixture goes even leaner. I would believe the engine would stumble or fail to maintain a combustable mixture and stop.
If you run rich-of-peak you lean to max EGT and then richen the mixture + 50°. If you then decend into more oxygen rich air the EGT should rise, it may or may not pass through max EGT. I would
think that would be your point of maximum EGT. I have never liked running lean-of-peak in piston engines. It doesn't seem to hurt the rotary, especially considering the fact that Tracy does it even
for takeoff. The operation lean-of-peak would probably cause high oxides of nitrogen emissions even if it didn't cause damage. I think that I spent to much time tuning 2-strokes. A minor excursion
into lean of peak could cause seizure.
Bill Jepson
No you are not. I was :) I historically get them reversed with the same result.
Here is the latest.
This chart is still a work in progress.
Start Operation. Power ...... Fuel Air...... Mixture .. EGT
---------------------------------------------------------------
LOP ..climb .... full ........Same decreasing richer higher
LOP ..descend .. reduced .....Same increasing leaner lower load on engine decreasing
ROP ..climb .... full ... ....Same decreasing richer lower
ROP ..descend .. reduced .. ..Same increasing leaner higher load on engine decreasing
The combination of increased power with richer mixture and higher EGT
while climbing is the valve killer while operating lean of peak.
I would like to make a further point now that I am thinking about it again.
We are trained to richen the mixture when we climb. If you start LOP
and go to rich you may increase the EGT. As you can see starting
with LOP peak is opposite to what we are taught.
There are some secondary effects here.
Pull back the throttle when descending.
Keep the throttle the same.
Increase the prop pitch when descending.
Leave the prop pitch the same.
Decrease the prop pitch.
Perhaps a few others. My point is one must fly all these scenarios
to see what happens to the EGT. A computer controlling the mixture based
on the EGT is the answer.
We in the rotary world don't need it.
Paul Lamar
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