Thanks Buck for your answer that helps alot. I would have never thought of multiplying the 2 numbers i was looking for a 15X8 but tower didnt have that size and i got the closest i could to it. I looked on the internet through several different forums on this. and visited many links to differnt types of 3 bladed props that were 15X8 but there pretty pricey.

There is a zinger Site that has a 3 bladed wooden prop that size. But considering that i might damage the prop and i'm experimenting i didnt want to spend to much on the prop.

http://www.zingerpropeller.com/3_bladed_Propeller.htm

Appriciate the input[sm=thumbup.gif]