If you want to come up with some kind of prop aspect ratio, you must
come up with an artificial area based on Q times element area to divide
into span-squared; with a rectangular plan form prop, that area
distribution would look like a very narrow hub expanding exponentially
to a very wide tip. You're wasting your time chasing this elusive
"induced drag" based on aspect ratio. You can solve for this ID by
looking at the inclination of the 2D lift when induced AOA is solved.
When you solve for IAOA, you don't have to come up with an AR-modified
lift slope. You only do that when you don't know the IAOA! Don't forget
to apply some form of lift roll-off as you near the tip. I have found
the Shrenck method works well.
   Since you seem to question my approach, don't forget that my prop
design equations give prop performance to much better than 1%! My
estimates of a prop's performance on a plane it was designed for get
within 1 mph at a given rpm and dalt. Ask Tom Aberle! I'm just trying to
get you back on track and save you some time with what I have found
through my chase of prop info; if you are not interested in what I've
learned, let me know and I'll cease and desist!

Paul Lipps.

I am not questioning your approach Paul. I think highly of the
results. What ever method you use for  designing the prop
obviously must work. My main concern is finding a simple
mathematical spread sheet that will accurately predict
the twist, pitch and plan form so we can use it to recommend
a particular prop design given the wide disparity
in rotary engine powered aircraft types. This has been an
on going proplem for us for the past seven years.

Perhaps you have one that you can share.

Paul Lamar ...No rotor no motor.

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