When I went from the 13x4(3D) from apc, it made the pull out unbelivable! Raideron, I think that when you went from the apc to wood, you also reduced the rotaing mass of the prop and its letting the YS hit the revs alot quicker. The wood props have their good points and bad points. I wonder if they make a carbon fiber prop that can be used by the smaller engines?