Wayne,
I found just the opposite when I first started flying my Tipo with the Speed 13, I used a 11X71/4 Rev Up and the airplane was a bullet.
We have a Radar gun and checked my plane with it. on a down wind pass coming out of a split S we got 143 mph and 136 up wind.
I then changed to the 11X10 APC and the speed dropped to 106 along with the RPM. the Rossi still had enough torque to do the vertical maneuver's and was very smooth. ( sounds like a YS)
I have since dropped back to an 11X8 prop which seems to do better all around.
We will have the Radar gun with us if any want to check the speed of your plane..
See ya Friday.

Dave.