I have an RCV SP90 destined for my Top Flite P-51 temporarily mounted in a Goldberg Chipmunk. It has run exactly as described by the manufacturer. I have less than a gallon of fuel through mine and have been running an 18x12 prop. The idle is nice but very sensitive to adjust especially when the engine is new. Top end is 5500 rpm with the 18x12. I intend on trying some different props once I've got the first gallon through it. I have not experienced any overheating though it is not enclosed in a cowl yet.

There is a brief video of it running during break in on my P-51 page http://home.comcast.net/~keblair/P51D.htm

Kent