da Rock, while I have no specific site to send you, you could try the search function on RCU. I have read on many threads here where a 3 blade will not perform like a 2 blade, and 4 blades are for static only. It has something to with the Reynolds number, which has something to do with the size of air molecules and their effect on full scale vs models (rough definition). This month's RC Report had an article explaining how to make a four blade for static.