i wouldn't put a 13x4 prop on a 46fx. you will overload the engine and overheat easily. the biggest i put on my 46fx was a 12x5, which was on my funtana. now i have a os .70 surpass with a 13x4w on it, good combo. I had good results with the 11x5 on my 46fx also. anything above a 12x5 on the 46fx is just going to give problems. the engine wont run in the correct RPM range. If your going to get another plane, you may want to try a different engine, it sounds like from the posts you guys put the .46 just ain't enough. good luck and happy flying!

sean