I just got a used Saito 50 and want to use it for funfly plane what prop can a Saito 50 swing.
Thank you for your help

http://www.horizonhobby.com should have the manual. There should be a matrix in there for various prop sizes and their applications.

This site has some good info:

http://www.saito-engines.info/

BGW45 thanks alot, that site has some very good info.

I like the APC 12 X 5 on the Saito 50 but it seems to pull the 12 X 6 just fine

If you are going for 3D the plane had better be light weight

For 3D run a APC 12.75 X 3.75 or a APC 13 X 4