This is wrong use of the shim.Creationist127 wrote: ↑February 3rd, 2020, 8:45 amAs far as I know, the shim works best. To use one, you put it between the wing mount and the motor stick, behind one of the wing posts, so that it warps the wing, making one side of the wing tilted higher than the other. To my knowledge, this makes one side rise more than the other in the air, making the plane turn. To change direction, put the shim under the other wing post and tilt the rudder in the other direction.
The plane is turned with rudder (primarily rudder on the kits this year, though thrust line and stab tilt may help on a self-design). If the plane rolls in and does not climb (either races in a circle with the inboard wing low, or even spirals into the ground), you need the shim to raise the LE of the inboard wing a mm or two to level the plane and convert the racing into climb. Again, a variable to keep track of!
I team I helped via text and video in Southern NM also won their regional this weekend. They had a plane that they could get trimmed for low power flight, but it would not climb. After many exchanged videos, last Thursday they added shim, and the plane climbed to the ceiling in Regionals. They were the only plane to climb reasonably at all, and they won hands down.
Last year at Nationals our plane nearly hit the wall. After half a lap, it rolled in and side-skidded for about 30 feet, then righted itself. A small touch of left wing wash in would have solved that issue. It only presented at the highest torque levels.
So don't use shim to turn the plane. Use rudder. get it turning and flying level on low power. Then if it rolls inward at higher power, add inboard wing shim to the LE.
This is caused because rudder yaws the plane, causing the outer wind to present to the oncoming air, and lifts the outer wing more than the inner wing. This gets worse at higher speed.
Coach Chuck
