I don't know if anyone can help on this - I'm looking for someone practical who also knows the theory (Genghis??).
I am looking for a (relatively) simple formula that gives the relationship between RPM, Power and Altitude for a fixed pitch propellor - but have had no luck so far
The aim of the exercise is to be able to produce a table giving RPM required for various power settings at various altitudes. The input data being a full throttle run at a know density altitude - giving a reference power (100%), altitude (from the altimeter) and RPM (from tacho).
I have so far managed to find a formula giving the relationship between Power and RPM (assuming the same altitude) at:
How To Determine The Part-Throttle RPM of a Fixed Pitch Propeller At a Given Horsepower
HP2 = HP1 (RPM2 /RPM1 )^3
where
HP2 = part-throttle hp
HP1 = full throttle hp
RPM2= part-throttle rpm
RPM1 = full throttle rpm
- though I'm prepared to be convinced that this is not correct (it doesn't seem to accurately fit a POH I've tried to test it against).
Any help on this one would be appreciated
OC619
P.S. I do have a maths/engineering based degree - but it's a couple of decades since I really had to use it (so please be gentle with me)
