For a profile 3D (Yak), the best engine is a Moki 61 LS.
Or, maybe, a Moki 210?
I am not sure. But I like Moki, so I will suggest Moki. Hey, Webras are also pretty good.
But the more I think on it, the more I am sure that THIS engine is best for your purpose:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBY98
Nothing beats this engine on a 3D plane!
NOTHING!
The plane will fly like nothing you have ever imagined with it.
Marc