Prop Pitch Question

[737]

I have a Rotax 582 with a 2.62:1 C type gearbox. I need to know the correct pitch for a 68" GSC 3 blade prop. It will be fitted to a Kitfox.

Many thanks,

737

[Mark 1]

Not an easy question to answer. Often it is best to take the propeller manufacturers recommendation or use the experience of someone else.

The nominal pitch is easy to calculate:
Pitch(inches) = (TAS(MPH)*63360)/(60*RPM)

where TAS is the cruise speed and RPM is the propeller RPM.

This then has to be increased by 5-10% for the 'slip factor'.

Of course the relationship between cruise speed and RPM will vary with propeller pitch.

[Pilotage]

Go to http://www.bmaa.org/tads.htm, download TIL 011, the answer will be in the graphs in there.

P