My Model Tech Calypso came set up for retracts. I put Hobbicos in it and they work fine. With the 91 FX I'm using a 13/8 3 blade master and have plenty of ground clearance. I originally used a 13/10 APC but I couldn't keep the airplane slow on down lines and had to set up for landing starting in the next county. The 3 blade fixed that. The plane is smallish (for pattern) and very clean. The wing is also not thick.