Guys, thanks for the replies. Firstly I don't have a manifold pressure guage,
but
only an old car economy guage to give warning of carburettor ice build-up.
Permission was given for this and it works very well, although the needle moves
in the opposite sense. Because my 912 ULS engine isn't turbo boosted, there's
no chance of "overboosting".
Now to my puzzlement about the consequence of using a constant speed Airmaster
propeller and changes in horsepower without changing rpm. In my simple brain,
if I have 5000 rpm selected for cruise and move the throttle within the governed
range, then the horsepower MUST increase as I move the throttle from lowest
position at which 5000 rpm can be maintained to the fully forward position.
Therefore the tables provided in the engine manual become nonsensical regarding
RPM vs horsepower. It's more likely to me that the only remaining approximation
to horsepower being produced must be manifold pressure.
So assuming I generally cruise at 4700 RPM for aural comfort, indicating 115 to
120 KIAS and at a fixed throttle position, what remains for me to have an idea
of what % power I'm using is fuel consumption. Somehow I've acquired the idea
that 18.5 litres/hour indicates about 75% power.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=457721#457721
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