I understand, I guess I'm happy because I have never had any luck with OS engines for my helis, I've had three, two of them I bought brand new and one used, none worked fine, always had some problems, then I have replaced the OS with HS engine, and it still runs great after at least 15 gallons of fuel through it, now I've installed the tt39 and it had only three flights on it, however, I've had 50 sized raptor before and it didn't perform as well as my 30 does with this engine installed. I'll let you know if I run into any problems with this engine
