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Propellors

Category: 2 Stroke Technical Questions one month ago

Greetings all.

First post with a technical question.

kitfox 3 with 582 engine, recently replaced prop due to corrosion in the hub and blade roots of the old prop (Arblast helice)

new prop is different in that it has wide chord at the roots and narrows words the tip. It also has considerable washout from root to tip. ( I shall withhold the manufacturer name for the moment)

To get max static RPM 6200, the pitch at the tip is set to 9 degrees. Sounds small I know but don't forget the washout.!

Fantastic takeoff and climb but lost about 20mph in cruise, repitching coarser improves things slightly, static rpm is lower of course and while the aircraft is slightly faster in cruise, it's nowhere near what it was.. however coarsening prop pushes egt up to limits and at one point in the Rev band 5200rpm I encountered the dreaded tinkling of detonation.

my own impression is that this prop would be better suited to a faster aircraft, where the tips would be more efficient. Also the  wide part of the blade chord is just in front of the round cowling which hinders its efficiency. (I think?).

I would appreciate any opinions on offer,   Thanks

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