I bought a US 40cc gas engine for a 25% 3D Cap from Top model.
I realized that engine is not suitable for that plane and I decided to go with DA50, which I think was a good decision.
Now, I am trying to find a right plane for the US 40cc.
I appreciate recommendatioins for the airplane for that engine.
Will that be too much for 25% cub?

The perfect engine for a 1/4 scale Cub is an FS 1.2, the main problem with this size engine for the Cub is not that it will overpower the airplane, a throttle takes care of that, but the size is much more than a Cub nose can handle, although some people don't care about that, to me is very important.
My Bellanca 1/4 scale Decathlon had a Quadra 35 for power (much larger nose area than a Cub), and it was just perfect (at 20 lbs ready to fly weight), I've also seen 1/4 scale Nosen Aeroncas with this engine and it fit OK too, that engine will power just about any type of airplane up to about 15-25 lbs. weight, but then again if you want a 27 % (82" wingspan) Extra or Cap that may only weigh 15 lbs but you want to do 3 D manuevers with, it would probably be not the right engine for it, it would fly them very well, but not 3 D.
Most large biplanes and high wing type airplanes would be the best aircraft for that type engine at the weight I mentioned earlier.

I've had a Quadra 42 (same engine as the US41) sitting on my self for 12 years waiting for the right plane. It's too heavy for some, not enough power for others and too heavy & not enough power for others. It's a great engine I used it back in 1991 on a 1/3 Byron Pitts ( can you say underpowered ) and it starts on the first crank every time and no ignition to worry about. I bought a Brison 2.4 and the engine is 1 lb. lighter, turns the same prop 1000 rpm more than the Q42 and doesn't shake like a AA/F dragster at idle.

I'm going to watch this thread for a while - I got lots of time - it's been 12 years already.

Try a giant scale Top Flite P-51 ARF.

As a matter of fact I have a Topflite 1/5 P-51 ARF sitting about 5 feet away from me right now waiting for it's maiden and yes I looked long and hard at putting the Q42 in it, but chickened out after reading a lot of reports that it was marginal power. I opted for the Brison 2.4, as I said 1 lb. lighter and 8000 on a 18-10 instead of 7000.

You might do a search for Memphisbelle's posts on the US 41. I bought his YA P47, which has a US41. It provides completely adequate scale flight, with great big loops, four point rolls, etc. I like it because, with the custom exhaust he built, the cowl is complete, no holes.

He had this engine in a 4-Star 120, and hovered with it. Another of his current planes is a Dynaflite Chipmunk with another US41, and it quite aerobatic. For the money, it's hard to beat this engine.

Good luck,
Dave Olson

I too have a Quadra 40 looking for a new home. What about a H9 Taylor Craft?? too much engine for it?????

PS: I'll keep watchin this post too!

I am thinking about war birds for this engine.
Since we won't do 3d or pattern flight with them, as long as weight and power match, I think that would be a good candidate.
I am watching the specs of World Model Spirfire G.S. With the wing span of 80" and 13 lb weight, looks like it's gonna work.
I think the challenge will come for fitting the engine inside the cowl.