Hi Paul-

 I took some time to massage the data from the final run.  I added a column
 averaging the two rotor pressures, I added a column which identifies the
 time of the most recent CAS pulse, and I computed last known RPM.

 Mark

 Mark sent the whole 9.2 megabyte spread sheet so I cut just the relevant
 stuff and plotted it. 9.2 megs is too big to publish.

 The difference in the amplitude of the front and rear rotor waves is
 somewhat of
 a mystery at the moment. It could be the way the pressure tap hole was
 machined
 in the runner tube. They were hand drilled. If it is not perpendicular you
 could get some strange effects.

 This RPM is roughly where the tubes were tuned for so you can see the
 pressure
 waves peaks happen around bottom dead center and front (car blue) and rear
 (red)
 rotors are roughly in phase and they add. Mark averaged them (yellow
line).
 The green line is the CAS signal.

 Mark, please redo do it and just add the rotor pressures  together.
 That will give us a better idea of how much total air the engine is
 getting.
 Do not divide by two.

 The result should be well over 1.5 volts and well over atmospheric
 pressure.
 Atmospheric pressure is 1.8 volts at sea level and Mark's air port is
 6800 feet. At 6600 RPM the prop tips were near supersonic so that
 was the max static RPM of this engine at what ever power it could
 make at 6600 RPM and 6800 feet. Once the airplane picks up speed the
 engine RPM will increase and so too will the engine HP.

 BTW we are at the response limit of the pressure sensors. These are the
 same type Tracy is using. The data acq could sample data tens times as
fast
 but for the fact the pressure sensors are not up to it.

 Right now the engine is under propped. Mark will rerun some of the data
 when he gets the right prop on there. Never the less we had to
 weigh the tail down with a steel beam to keep the airplane from
 nosing over.

 Paul Lamar

Hi Paul-

Do you want me to create the same additional fields (pressure1+pressure2;
rpm, etc) on any of the earlier data runs?

mrs

Would not hurt if you have the time.

Paul Lamar

Here's file 11.

All data prior to junk11 does not have the CAS pulses in it.  Doesn't seem
like there is a lot of point in massaging it when I won't be able to derive
RPM.

mrs

You are right. You will need some more data when you get the final prop
anyway. Here is a plot of 11 with the two pressure curves added together.

Paul Lamar