X-Mozilla-Keys:                                                                                 

For Jeff Spitzer,
Jeff, are you planning to use a hollow shaft for the Prop drive shaft?  One
of my interests is for a cockpit controllable prop, operated mechanically
through a hollow drive shaft for either a belt, chain, or gear PSRU.

I'm building a Bearhawk so want the prop at the top of the cowling for
maximum prop ground clearance.  I want to turn a big prop slowly (relatively)
so could use a pitch change feature to advantage.

Rob Gaddy

The rotary is rather deceptive in that it is only about 12 inches in 
diameter. Most sprockets are at least ten inches in dia. and if you
raise
it enough to get something through a hollow prop shaft you will
not save that much on prop height. The worst part as far as 
the cowl shape is concerned is the sprocket is right behind
the prop whereas with a Ross type planetary the PSRU has a better
shape for streamling. You could of course use a long prop extension
but that has its drawbacks as well. (No bearing out where it counts.)
For that inch or two you save in prop height you are left with little
room under the engine for a single rad as you must lower the engine
about five or six inches.

Paul Lamar
 
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