The PT-40 has two options for wing dihedral or angle. One has about 2 1/2 inches of angle total and the other has almost 8 inches. Make sure you build the low dihedral (2 1/2 inches) option. The manual suggests that beginners build the 8 inch wing - DON'T DO IT! The 8 inch wing is only for 3 channel (rudder control not ailerons) flying and will fly like crud if you try to fly it with ailerons. I'm so passionate about this because I spent a lot of time last summer butchering a students wing to change the angle so the plane would fly right.