Trim trouble

Try giving it a little right thrust (the prop shaft ponting 2 degree right), that should make it better.

Or right rudder.

You need to check the incidence of each wing half. If the ailerons are not the same when trimmed for level flight, they are warped. The side with the up trim has what is called wash-in. The wing is warped with the leading edge higher at the tip than the root.

Also, did you balance the plane laterally (through the thrust line) to make sure one side isn't heavier than the other? Many planes with side mounted engines need this balance.

What Paul and others have said.

I would check for left thrust in the engine, or a warp toward the left in the fuselage that is pulling the model to the left in the yaw axis. Right thrust is the cure for both, if present.

Ed Cregger

In full scale Citabria it is normal, at full throtle right rudder at idle for landing left rudder. P factor has lot to do with it. Some left thrust on engine might help some. Also as the airspeed increases rudder input is less or none. John Altoona R/C Club in Pennsylvania.

Are you sure you don't want to rethink adding in LEFT thrust on the engine?

MJC

On 1/6/2004 4:48 PM Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

What everyone is saying about the right thrust is correct. The EASIEST WAY to put right thrust (or left, down etc. thrust) is go to your local hardware store. In the fastener section you will find washers. They come in a variety of thicknesses (brass, steel, fiber, nylon). Get several of each thickness so you have a variety of "angles" to choose from. Make sure you bring a bolt of the correct size with you to "size" the hole.

Sory for the mistake in typing. Left thrust should read right thrust lookin from tail forward. John Altoona R/C club in Pensylvania.

Yawing left when adding power is perfectly normal and is controlled by using right rudder. Get used to it. Adding right thrust might make things easier at first, but then you have to deal with a right-yawing tendency in cruise, and screwed-up aerobatic behavior. As I've said before, there are four forces that yaw the airplane left. P-factor, or the higher angle of attack of the downgoing blade when the nose is well up at low speed, will pull the nose left since the centre of thrust is off to the right a bit. The rotating slipstream off the prop will strike the fin on the left and push tail right, nose left. Gyroscopic propeller forces will pull the nose left as the tail comes up on takeoff, and the torque reaction on the fuselage will put more weight on the left wheel on takeoff and increase drag on that side. The first two forces are strong and are what the original poster is dealing with.

Dan