The 46FX will be a nice change for you. Don't go smaller than a 11" prop. It will makes lots of noise and not give you the benefit of the larger engine. I tried lots of different props on trainers with 46 engines and found the best choice seems to be a MAS 11-5. It will give you lots of pull to get you out of trouble if you need to and will act as a brake for easy landings. It will also give the trainer respectable speed for cruising. You won't be sorry. [8D]