Large Model Association Forum

Can anyone give me some advice. I want to fit 4 blade props to two 25 cc petrol engines, The engines are advised to be run in on 17/8 props when run in 18/8or10.
I would like advice on the diameter and pitch I should use. I have been told that 1" per extra blade is correct but I do not want to buy the wrong props.
I will be grateful for any information. thanks TERRY.

The Windsor propeller website gives useful info about changing from two to three blade props but they don't cover 4 blades.

http://www.zingerpropeller.com/_2_blade_.htm


The answers you need are here,

thanks for the information. I am now in a position to make the right choice of props. thanks very much TERRY.