View Full Version : I have a prop problem

08-21-2011, 06:47 PM
I bought a prop for my UL-1, Grimracer recommends that I use a L40 x 57 AQUB9760. I put it on and my speed drop from 45 mph to about 10 mph any ideas as to what the problem maybe my batteries are 2s 40c 7.4. The prop has been sharpen and balance. :flame42: