Speed is relative. Speed will depend on plane setup, drag, prop, weather, fuel, piloting style and other things. For this plane, you can gain more speed by installing retracts with doors and smoothing over other draggy bits than you can by adding bigger engines. The reason I suggested the Jett engine is you can order it reversed. This will open up all of the standard pitch props for you to use. I figure you should be able to get this bird up to about 120 mph if you work at it with the Jett .50.

Personally I don't measure speed on models. If I want to go fast I pick up a plane built for speed, a quickie, pylon racer or a sport jet. This plane is more of a sport plane, closer to a pattern ship than a speed demon. I figure mine is doing 70-80 mph using a 6 pitch prop and an untuned pipe on the YS 45. Math says I should be able to get to 110 or so once the pipe is tuned and I put on a 9 pitch.

Mark