"Bryan.G. Wilkinsonn" wrote:

Can I seek some advice?

I have been advised to fit a manifold pressure gauge when a variable pitch
prop. is used.

I am completing the construction of the instrument panel so now is the time
to make room for one.

Can anyone explain the possible reasoning behind this, and how the pressure
gauge is used in flight.

Also, does anyone know of a supplier for a fuel pressure transducer.

#333 is a tri-gear with a 912S.

best regards
Dennis

It comes from the "over square is bad" scenario. Too much manifold pressure and 
not enough RPM is thought to be bad for piston engines by some. That is why manifold 
pressure gages are included on airplanes with constant speed or variable pitch props.
You will be able to check and make sure you do not have too much throttle opening 
for the RPM of the engine.

A second, and perhaps more important reason is, one can calculate, or look up, the
percentage
of power one is demanding from the engine if manifold pressure and RPM is known.
Most piston aircraft engines are limited 75% peak power for continuous operation.
 
Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org