hey guys, it looks like you want to get more out of those trainers and I don't blame ya. I have a tower hobbies .40 size trainer and it was a blast. It had the tower hobbies .46. The engine is powerful but overall ran crappy. The plane had no problems doing loop after loop. The best thing I have done so far is spend 69.99 bucks on my World models "Skyraider Mach-2", which is a 40 size low wing aerobatic trainer. I put the OS .46AX on there and love it. I also now have a computer radio w/exponenial that makes landing so much easier. This plane has got to be perfect as a 2nd plane. So here is my 2 cents. Quite killing yourself on $4.00 props and running your engines lean and spend 69.99 on a new lighter ARF that will introduce you to a whole bunch more fun. HAPPY FLY'IN