Bill the Grump,

Between this statement, "When I was the test pilot!". and all of your
stories, you are a legend in your own right. Or is that in your own
mind?

You are a character... LOL. We do enjoy you here, even if you are the
Grump.

Bryan


(Badwater Bill) wrote in message . ..
Nice job Richard. Nice Job.

I might just add one more comment to clear something up a bit. When
you chose a prop, you design it so the tip speeds don't exceed 0.80
Mach, or 80% the speed of sound. As the propeller tips approach
speeds over that, the airflow can become super sonic even though the
prop tip is well below Mach-1. As you mentioned, that takes a lot of
energy that is wasted and is not available for thrust to create a
shock wave and sustain it.

When I was the test pilot on the OMABP RV-6A project, we used the
Chevy Vortec V-6 engine, the PSRU was specifically designed to turn
the prop at tip speed below 80% the speed of sound. Jess Meyers also
used a reduction ratio number that was about equal to the square root
of 2 to eliminate harmonics that could have resulted in reversed
torque pulses reflecting back into the engine. By using a reduction
ratio of 1.41 (or close to it) he eliminated many sympathetic
harmonics that may have occured.

BWB