An OS .46 AX can't turn a 12-6 or 12-7 to save its life. Even an 11-7 is reallya bit too much for best performance, unless the model is small & clean. The AX is barely (if at all) more powerfull than a .46 FX or TT .46 Pro. An APC (or even MAS) 11-6 is a really good all-around prop for that engine, & a 12-4 APC is right on the money for 3D.