Pine Pienaar wrote:

Hi

Does anyone have a copy of Prop Optimizer by Bates that can run me a

couple

of design's.
I'm trying to model a 2 and 3 blade prop through Rhino 3D firstly to

learn

it and secondly because I heard that the most difficult part of

modeling a

prop is to get the hub area right.

I would like to use correct figures as I'm going to make a sample

prop to

run on a test stand.

Please let me know what is needed for input data.

Many Thanks

Pine Pienaar
pine@cpro.co.za
Lancair 360 #664

vjaqua wrote:

Pine - The center 20 percent radius portion of the propeller has almost

no impact

on performance, and in many cases is almost, if not completely,

encompassed by

the spinner. My programs essentially ignore this area, especially since

true

helical pitch would usually result in very steep angles for these

points. I can

give you a starting point prop configuration with data on engine shaft
horsepower, prop shaft rpm at that power,and a realistic value for

airplane top

speed at that power. If you have some diameter limitations based on gear
clearance, that can be considered also. in most cases optimum

performance is

realized with the maximum diameter allowed by tip speed and clearance.
Vance

I agree that prop performance itself is almost unrelated to the inboard
portion of the blade but this is NOT the same thing as saying it is not
important.   The IVO prop test results that I did awhile back showed that
the center 23 inches diameter (about 30% of radius) can generate a lot of
drag.  This portion does not produce a lot (or any) thrust but make sure it
doesn't produce drag.

Tracy Crook
rws@altavista.net
www.rotaryaviation.com

vjaqua wrote:

Tracy - With a fast plane like yours, I think that well over half the prop
diameter on an Ivo prop is at a disastrously wrong pitch - Vance

Sounds like a drag GENERATOR :-)

Paul Lamar
 
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