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Date: Wed, 21 Dec 2011 15:33:49 -0500
From: Ernest Christley <echristley@att.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: off topic, propeller carving and paint
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Bill Bradburry wrote:
> That is true, but if I was going to go with something else, I would try to
> find something that will turn my prop close to the 2700 that most props are
> designed for.  That means that I would look for something in the 2.2-2.4
> ratio range, not 3.17.  That ratio will mean your prop will never get more
> than 2000 rpm with the rotary.
> 

I'm not planning to switch my gearbox, and I hear those rotaries will turn faster than 6400rpm 8*)  I'm also not
particularly concerned with what other props are designed for, other than as object lessons, as the chances of me
switching out to a prop that I haven't built are exceedingly small.

We're talking a clean slate here, Bill.  Carefully consider this question.

Everything is a compromise.  Mainstream propellers are not designed to be as efficient as possible.  They are designed
to make the entire system as efficient as possible.  Generally, that prop is going to be bolted to the crank of a
4-cylinder piston engine that needs to spin >2000rpm to smooth out torque reversals.  If you could alter the Laws of
Physics to change how the engine operates, how would you change it, and how would that affect the design of your prop?