I was running an 11x5 on my Somethin' Extra. It would just barely climb, very very slowly or sometimes not at all. Then today I switched to a APC 12.25 x 3.75. I can go from a hover to a climb. Its still slow but I love this prop. It works fine on my TT. 46. I've been getting 1 1/2 - 2 torque rolls before I would fall out. I have to cut the power when I land so as not break the prop because I only have 2.