Does the motor on the Curtiss Junior need to be re-timed to run backwards?

From : Don Stackhouse

Excellent question, and no, it doesn't, it is neutral-timed and runs equally well in both directions. It's just as well, since its timing isn't adjustable anyway!

For that matter, the direction it turns in the Junior is actually the "normal" direction in the first place. The gearbox makes the prop turn the opposite direction from the motor, so in the tractor airplanes (the vast majority of the RK models), you have to connect the motor with "reverse" polarity (i.e.: you connect the negative lead from the speed controller to the "+" terminal on the motor).

However, because the Junior uses the same right-handed prop but as a pusher, the positive lead from the Junior's speed controller goes to the "+" terminal on the motor.

Life sure is confusing sometimes. Just follow the directions in the instructions for each model, and double check that the air blows aft towards the tail when you advance the throttle, and everything will be fine. Still, you'd be surprised how many questions we get about that!

Don Stackhouse
DJ Aerotech