Rough sanded the second wing half today including the leading and trailing edges and the wing tip. Then I worked on them to join them - for a Kougar as with any airframe this is an important step in the build process. If the wing has a twist built into it it simply won't loop straight and I have known many Kougar owners who have this issue. I believe it is because of the rough sanding done prior to joining the wings. This gives a rough shape to the leading and trailing edge which may not match perfectly on each half. My solution is to measure the centerline of the wing based on the thickness of the foam and make sure that both halves line up based on that centerline. Then once they are aligned and glued together one can shape them finally to the desired complementary shape of the foam airfoil.

The picture shows this centerline and it looks off but I think that is just an optical illusion - I measured carefully and even compared the top and bottom halves on each wing panel to ensure that they were as close to right on as I could get reasonably.