After seeing Perry's prop, and having to wait for the funds to buy a
prop, I've been mulling over the idea of building my own prop. I could
go with a two bladed or three. I'm assuming a top speed of around 210
mph, 190 hp, 72 inch diameter prop 2.85/1 redrive turning up to 7000
rpm. I'm working out the pitch angles on the blade with 77inches pitch
at the tip. If I do this, I want to make the blades in a monolithic
pour, rather than making the blades first and then fixing them into a
hub. I have acess to a metal lathe, so I could turn inserts for prop
bolt bushings. Still in the thinking stage-

what type of planform for the blades- rectangular, or eliptical? How
wide should the cord be on the blades? Thickness?

should I go with a 2 or 3 bladed prop? I want to be able to have a nice
cruise speed, but still be able to get into reasonably short airstrips.
Emphasis on speed over stol capabliities.

Where do I get carbon fiber "yarn"? I know where to get fabric, but not
yarn.

Anyone have the exact measurements of an SAE 2 hub?

Any input about pitch?

Any and all input is welcome. I'm trying to conceptuallize a molding
device that I can build that would enable me to make a monlithic layup
and force resin uniformly throughout the mold. I like the idea of
winding carbon fiber throughout the mold and around the prop bolt
bushings to make the strongest possible prop.

Brian Trubee
RV-4/13 BREW


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