ORIGINAL: T28RON
No. The engine can handle a larger prop. Accoding to the specs it will handle up to a 20" prop. I don't want to have it maxed out. I am thinking a Zinger 18 X 8. I have an APC 17 X 8. That will probably work but like the looks of the Wooden props. I am running 25%. I tried to locate cubman but can only find his profile and the email. I tried to email him but it comes back "not deliverable". I am not to good at surfing this site. There is nothing easy about it unless you live on it and I don't have the time to surf for hours. Why can't these people make it easy for the lay person. Maybe it's just me. !!!!!
Ron
Since you have it, I'd give the APC 17-8 a try and see if that is closer to the performance you want. You stated you were looking to increase climb rate and speed in your earlier post. The usual rule is to increase pitch to gain speed and diameter to gain climb ability. A Cub is a high drag airframe and best climb performance will probably occur with a larger diameter, lower pitch prop. The 18-8 prop you mentioned, has the same pitch as the smaller diameter props, so while it may produce more static thrust, it probably won't increase speed much, if at all. You stated the engine is rated for up to 20" props. If a 20 x 8 is ok for the engine, then a 18 x 10 should also be close to the same load on the engine. The 18 x 10 should produce higher speed than the 18 x 8, but with a high drag airframe like a cub, any changes will be slight. If the 18 x 10 is too much, a 17 x 10 just might do the trick. Since all these props are expensive to try, I'd attempt to locate users of that particular engine in the online forums to compare performance figures. They may provide the answer for you, so you don't have to waste money on props you don't need.
Good Luck!
DT56