I have 2 McCoy 40's that I have been running for awhile, and they both run about the same. Just wondering what you all use for props. I started out with a 10-5 APC and my Magician was to fast where the engine wanted to run. If I don't set it lean enough, it burps pretty bad on transitions to outsides, this still in a steady 4 stroke run. Next I went to a 11-5 APC and it was better but still to fast. I finally went to a 12-6 APC cut down to 11", and this prop is working better than anything I have tried so far. It loads the engine enough that I can set the needle fairly rich, but the engine doesn't burp, and the speed is very managable. The engine seems to really like this prop and just breaks a little in manuevers, but does most of the pattern in a solid 4 stroke. If I had the prop clearance I think I would try a full 12-6 or maybe a 12-5. I just did not think these old tech. motors would pull props this big. I even tried a Rev-Up 11-7&1/2 cut down to 10, and that is when I found that it liked to be loaded with a big prop. Anybody else have this experiance with McCoy 40's?

Lou; These are both old stock Red Head 40's. Sorry I forgot to mention that. Magician weighs about 37 OZ. and is built stock with moveable flaps. Fuel is Sig 5% nitro, 25% all castor, with added castor to bring it up to 28%. Also running a uniflow tank, but with both vents open to make it standard vent. It seems to run best that way with just a little speedup at the end.

I should have had a clue when John Wright mentioned he was flying his Magician with a McCoy 40 with a 10-8 Rev-up prop so as to quiet it down for a park flyer. He related that it worked just fine, was much quieter, and the engine did not seem to care one bit. These McCoy's are luggers.