First our static engine RPM was only 5200 RPM.

The 82 inch prop was turning  only 1730 RPM
at 5200 RPM so the prop tips are only going 415 MPH.
Normally they get closer to Mach One at static RPM.

The 82 inch diameter static prop RPM IMHO should be higher.
I suspect the exhaust manifold by pass one inch hole is too
large. Our boost was only 5 psi. IMHO that should be closer
to 20 psi.  5 psi is about the boost you get in a stock
1995, 280 HP RX7 turbo.

We have a couple of heavy duty platform scales and
if we measure the landing gear weights we can calculate
the the prop torque and hence the HP.

We can also measure the static thrust with a calibrated garage
door spring I have.

I suspect the engine was not tuned for prop load.

We know the mixture was too lean as we richened
it up and got another 1000 RPM when it was 4000 RPM.

We got it so rich there was raw fuel in the exhaust
so it caught fire after we shut it off. Fortunately no
damage to the airplane. Quick response by a
few people with fire extinguishers close by.

We also found the waste gate was beginning to open
at this modest boost level. Very very strange!!!

There are a few things we can try. IMHO make
that hole in the manifold smaller or do away
with it altogether.

Nils Castillo has been our Motec guy and he is doing
wonderful work. The Motec system is rather easy to
tune as there is a PC USB interface. Unfortunately it
needs to be tuned when the prop is not stalled.

What would be better is a manual mixture and waste
gate controls on the instrument panel complete
with LCD displays of O2, MAP and waste gate position.
Basically a cockpit PC tap into the Motec. Perhaps a tablet ap
would do the trick.

So far the water cross counter flow cooling system is working great
except I suspect we still have steam pockets. It is labeled engine
temperature in the data log attached and never got over
106 degrees F. The sensor is in the hot pipe coming
out of the engine. Obviously we still have modest HP.

The oil temperature is a little above room temperature
and we ran the engine today six times in the space
of two hours. It takes a lot to heat 4 gallons of oil.

Paul Lamar

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