I am new to R/C airplanes, however not new to nitro engines. I have been running nitro cars for several years now. The situation I am in right now has to do with a TT Pro 61 that I recently got. It was used, for about 10 flights, when I got it. I put it in my Ultra stick 40 which made the plane scream. I was told that proper break in procedures were followed and from the performance and condition of the engine I would have no doubt about that.

The problem I am having with it is this. It primes with 1 flip of the prop, starts right up and idles great. On the ground it transitions perfectly, once warmed up that is. However the first time I went to take off it hicupped a little between 1/2 to 2/3 throttle but the took off. Then after flying for a few minutes at a constant throttle it hicupped and died when I went to quickly transition. I got it down in one piece and leaned it out about 1/4 - 1/2 turn. She ran great for a couple of flights after that. I then went to test the vertical abbilities and she hicupped towards the top. And during the same flight hicupped again on a quick transition but didn't die either time. I am used to cars and in that case it is saying that it is too rich. Is this the same concept with planes? The thing that I am not getting is that it runs and transitions great while on the ground or a buddy holding it at any attitude but when she gets in the air it starts to hicup. Am I missing something here? I am affraid to lean it out too much in fear of destroying what appears to be a great performing engine.