Hey again,
Yea, thanks for the info. I tried an APC 11x5.5 prop and when i was flying last week and gave off a weird sound. You know when you fly vertical until the plane slows down and starts falling back down but still with the nose pointing vertical, it makes a sound as if its cutting the air. Well, thats what the 11x5.5 sounded like, but all the way through.

Cheers