It's been a while since I asked the questions. Now I'm a little older by experience of using these hinges. After I got some experience and learned how to install them, they are my favorite hinges ever

I uses poliurethane with great success and I had no problem with hinges pushed out or leaking the foam while curing. That's how I do it now:

1. I mark the center line on the TE of the hinged wing. I don't use any jig as it doesn't work well [:'(], Just measure the center point on bothe ends and use metal ruler to draw the straight line.

2. Then I mark the places where the hinge should be on thet line (I know that before because I have already prepared balsa blocks on the TE for the hinge support[8D]).

3. I drill holes for hinges. Now the tricky part is to drill them straight, means square to the TE. Because I don't have a press drill big enough to put a wing in there I start with small 1/16 drill mounted on Dremell, then I go to bigger and bigger. The last dril size I use on slow speed drill so the hinge goes there very tight

4. I made a sharp tip nylon screw that has diameter of the hinge. The sharp tip shows very precise the center of the hole and marks a spot on the LE of the control surface. So I insert this screw into the first hinge hole exposing a sharp tip just a bit. Then I fit the control surface to the wing and when it is where it shoud be, I press it to the TE of the wing, so sharp point of the screw marks the spot on the LE of the control surface.

5. Now I drill the hole in that spot for the first hinge. Again I use step up drill sizes and the final drill is used on very low speed, so the fit is very tight.

6. I remove the sharp point screw from the first hole and move it to the last hole in the wing's TE. Then I insert Robart hinge in the first hole (in the wing and control surface) and try fit the control surface. Of course it is perfect aligned

7. I align the other end of the contro surface with the wing and when everything is OK I press it to mark the spot by exposed sharp tip of the nylon screw.

8. Remove the surface from the wing (the first hinge) and drill the hole in the marked spot for the last hinge.

9. Now I replace the screw with the second Robart hinge and move the screw to other holes in the wing.

10 Again assembly the wing-control surface and press to mark the next hinge spot. Repeat it for all hinges in the surface every time adding one hinge at the time to new drilled hole.

It looks like a lot of work, but in fact it is not, and with all the tools already on hand and a little experience with drilling holes square to the LE/TE I put 4 hinges in the wing in less than 15 minutes. No binding at all.

Because my holes are very precise and hinges fit very tight in there there is no way the expanding foam glue would push the hinge out. BTW all holes are through the LE/TE (no "dead-end" holes). So the expanding foam has easier way to go inside the wing rather than trying to squeeze out be the hinge.


You are absolutely right here. The glue works much better when it has contact with loose wet fibers rather than hard sealed CA. And it is easy to press in tight fit hinge when the hole is "soft".