Hi, after installing the ailerons to my herr P-51 I noticed that there is a gap between them and trailing edges (about 1/16" or a bit more). It doesn't look right to me and I think the culprits are the hinges I used. Is this gap normal or should I reinstall them? Thanks!

You want to get the gap as small as possible. Although 1/16" isn't too much either. You could try to get the gap smaller, or you could just seal the gap with monokote when you cover the plane.

Ken

Depending on where you are in the evolution of a kit builder (or ARFer, for that matter), a 1/16" gap is about par for the course. I've flown lots of planes with that much gap, and most planes I see at the fields have that much gap or more. However, best practice is to seal the gap with monokote or ultracote strips. Doing so will give you better effectiveness of ailerons, smoother flying. Not doing so is no disaster, but as your flying gets better you'll have more incentive to do it.

There needs to be some gap just to allow the control surfaces to move their full range. Just seal it as stated above.

Actually, there does not need to be a gap for control surface movement. If you have a wedge shape on the front of the movable surface it can be tight against the vertical trailing edge of the fixed surface. You will need to recess the hinge pivot point (hinge pin) into the control surface 'wedge' to accomplish this.