Darrel,

You shouldn't have a problem unless your line constricts. If it does, use brass tubing to route the lines back from the tank (keeping the clunk toward the rear of the plane).

NM Mark,

Yup, it sounds like your thrust line is off. Set your wing to zero on your bench and put a level on your prop shaft to check.

Stick Jammer,

Pylon racers use the Hitec 225. Go with the metal gear version for extra durability. Also remember this is a copy of a plane designed around a lot more weight than we are building into this.

Speed will be a function of drag more than engine size (given the limited availability of pusher prop sizes). If you really want to do it right, the servos should all be moved inside the plane and retracts should be fitted with doors.

I still think the best engines are the reversed Jett's, my YS 45 seems to do a good job as well. Anyone considering different engines should do a search on the pusher F16 (Combat Models if I remember correctly). This subject was hashed to death years ago. The YS was always the winner back then but now we have more engine options. The key is getting to more prop solutions.

Mark M