Pine Pienaar wrote:

Hi Paul

Using the basic prop design programs and some excel pages I created using
the math taken from "Light Aircraft Design", and reverenced to "The design
of the Aeroplane, by Darrol Stinton" I'm still very confused :(

I don't have either book. Theory of Flight R. Von Mises is a classic
published by Dover. 
Quite a lot on props. 

Also Modern Prop and Duct Design by M. Hollmann has some QB Basic programs.
Available from AC Spruce.

I get various conflicting parameters.

Can I ask that "someone" run these numbers for me and let me have it so I
figure out what I doing wrong.
I use the following input data
BHP 180    RPM 2700    Sea level speed 240

That is a very clean airplane. What kind of airplane are we talking about
here.

Max blade length 72 although I use 70 in my calculations. Blade width, again
I'm guessing (according to the one book they use the average chord times
1.28 for blade station 1 and taper it down to 0.65 at station 10)
Surly the blade profile (planform) would have a impact on its efficiency.

So far I know of no program that takes plan form into account. Cord yes
plan form no.

I'm using 5.63" at station 1 (Ave 4.4")
Airplane frontal surface 1.05 ft^2    Cd 0.2 (I think)
Design altitude 8000 ft
I would like to use the Clark-Y blade profile as I think it would be more
robust and take possible stone damage better than the proposed NACA 16106

You would be giving up some eff. to use the Clark Y.

MANY, MANY
Thanks

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

The attached zip has some programs from Vance that work quite well.
There is a bunch of other stuff in there. Some works some does not.

Paul Lamar
 
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