I have a couple of OS .40s kicking around, and I would like to purchase a capable 3D aircraft. So, what are your suggestions for an ARF, build, or flatout? Thanks !</p>

Really depends on which OS .40 you have laying around. If you got something with a little more power then you might consider a OMP proyak ARF or a Mojo kit. I think the profiles are the best bang for the buck in the 3D category. I have never been a fan of profiles till I got one for myself. They are tons of fun and cheap to replace when you get too couragous and make campfire kindling out of them.

I have an Os 46la on a mojo .25 it is a great combo.

Yeah, a 40 would do well in a Mojo .25! I might need one in my hangar (if only money would allow another plane ).

I have an OS 40FP. It is 15-20 years old, but still runs well. Thoughts? Thanks!

Dave

Would the OS 40 FP hover a Mojo 40? Thanks!

A 40FP with the stock muffler will hover a 3 1/2 pound plane, but just barely. Replacing the stock muffler with a mousse can muffler will boost the power to hover a 4 pound plane, but again just barely.

The Mojo 40 usually comes out around 4 to 4 1/2 pounds, so the 40FP would not be a good match.

very good answer MCDDD I agree

Looks like it would be the Mojo 25 with the .40.  Thanks for the detailed response!!

Dave</p>

What prop would you use with the 40fp?

Usually 11x4 for 3D flying. Sometimes a 10x4, such as on a PBF.