RE: Monocote Hinges?????????????
Another approach is to make rolling hinges from strips of covering material. These are practically frictionless and if done for the full length of the ailerons will seal the gap. And they will hold onto the ailerons more strongly than any other method. Hard to describe in words, but here goes.
The aileron is held by adjacent strips of covering material (matching that on the wing and aileron) which are placed close alongside each other from one end of the aileron to the other. A strip will start on the top of the wing, go down through the gap and then adhere to the underside of the aileron. The next strip starts on the bottom of the wing and goes up through the gap to the top of the aileron. And just keep going.
The trick is how to get the adhesive to switch sides as it goes from top to bottom. This requires each strip to be made up of two pieces of covering joined, adhesive to adhesive, where they touch. The width of the overlap is critical and should be worked out by sample tests. The overlap must be great enough so that no adhesive touches the LE of the aileron or the TE of the wing. This is critical- you do not want the strips glued to the hinge area so the strips can just bend gently or "roll" as the aileron moves. But if the overlap is too great they will tend to stick up from the wing surface. Easy to work out in a few minutes.
The good news is that the strips can be made in batches. (I will make up some dimensions for this example.) Cut two pieces of covering 1" x 10". Overlap them on the long edge by 1/4" with the adhesive sides face to face. Place on a glass sheet and use a trim iron along the overlap to join them. You now have something that is 10" long by 1.75" wide. This is the stock from which you will slice off 1/2" strips. The strips are your hinges and they are ready to install. Actually not hard to do as there are no critical steps like cutting hinge slots. Just spend a mindless evening with the radio on and your iron hot and it goes quickly. I hope this makes some sense to you.
BTW, this is originally intended to work with mating surfaces that are rounded to best give the rolling effect. But I have salvaged a plane which had a square wing TE and only a rounded aileron LE. It should work OK on the common V-bevelled aileron LE. But it is not the way to go if the aileron LE has a slant bevel. .