egrave

I have a Cherokee airplane with a 70" wing. I have balance the plane every which way. I put it on a level plane and level the airplane. I measure the tip of the wing at both ends and they were the same I measure down both wing in increment of 3" and they were the same Checking for a twisted wing. But in order for this airplane to fly level the ailerons has to be 1/4" up on the right side and 1/4" down on the other side .What could be wrong.

jetmech05

elevators the same? if one is up the airplane would want to roll using aileron trim to stop the roll...laterail balance ok? or yaw causing a wing to fall and using aileron trim to correct...let us know what you find

egrave

Once I trim it out it flys level but in order for it to fly level one aileron has to be up 1/4" and the other one has to be down 1/4" I am trying to get it to fly level with the aileron level

red head

Disconnect the aileron servo arm, Center the servo (by turning the radio on ) then put the arm back on .Then READJUST the ailerons so they are level. It sounds like you didn't center your servo when you installed it. ENJOY !!! RED

Dorsal

My Feedback: (17)

You say you are measuring down the wing every 3 inches - Are you measuring the leading edge, the trailing edge, or both? Have you checked the wing is square to the centerline of the fuse by measuring from the tail to each wingtip? I'd still suspect a twisted wing, but another possibility is the rudder not being square and inducing some yaw at all times. You would need to offset that with aileron also. Or the horizontal stabilizer is not parallel with the wing.

Jburry

1/4" is alot of aileron. This is not a simple lateral balance problem, or it's a huge one. My vote goes elsewhere.

First, check that the rudder is straight. Out of trim rudders will cause the plane to roll due to dihedral (roll coupling).

If the rudder is straight, check that the fuse was built straight. Simply sight along it, if it's out much, you'll see it. If the fuse isn't straight, it'll have the same effect as rudder trim. You can work around it by applying opposite rudder trim, if repairing the warp is too much work.

Next, set the plane up on a table or something in a slightly nose-up attitude (5 degrees or so). Stand in front of the plane, directly in line with the fuse. Walk backwards, watching the underside of the wing. If the underside of one wing becomes visible before the other, a wing is warped.

Determine which one, and if you've covered with a heat shrink covering, you can twist the wing in the desired direction, and heat the resulting wrinkles out of the covering. The covering will correct minor warps. More extreme warps will require that the wing be uncovered, glue joints broken and remade until the wing is straight.

For sport planes, I perfer to have both wingtips warped downwards about 1 degree. This is called washout, and will help ensure stalls are straight ahead. It comes at the cost of more abrupt inverted stalls.

Hope this helps.

J