PPRuNe Forums - prop question

PPRuNe Forums (https://www.pprune.org/)

- Private Flying (https://www.pprune.org/private-flying-63/)

- - prop question (https://www.pprune.org/private-flying/135405-prop-question.html)

I've been sent a question:

Quote:

Propellers here [USA] are specified by diameter and pitch (travel per rev). I have a prop for a small plane in my posession made in France that is specified as 695-200-103. I know that the 695 is the diameter in mm but what do the other two numbers represent? I would expect the pitch to be about 600 mm as well.

any ideas?

The French usually specify diameter and pitch in centimetres. But,

A typical light aircraft prop is around 55-65" in diameter, with 40-60" pitch.

That would mean we should see one number in the region 140-165, and another in the region 100-150.

Based upon that, my best guess would be that the 695 is actually the radius (not diameter) in millimetres, the 200 probably signifies a 2-blade prop, and the 103 is proabably the pitch in centimetres.

So in inches, it's probably 54" x 40½", which would be about typical of the sort of prop fitted on something around C150 sized.

This is however educated guesswork having worked on quite a few French aeroplanes, and I don't actually know.

G

Thanks, Genghis - I think that 695 really is the diameter; a bit of educated guesswork makes me think that the propeller is from a Cri-Cri, which would presumably make it a rather unusual propeller. This is backed up by Google - a search for the numbers in question comes up with "Two-bladed composite MC 695 - 200 - 103" on a page called "Caractéristiques du CRICRI".

Going by Genghis's guessed at UK equivelent it seems a bit big to be from a Cri-Cri surely?

SS