Construction Details - Rib Sheeting and Aileron Hinges




Spring clamps work really well to hold the top and bottom sheeting to the ribs and to the leading and trailing edge tubes while lining everything up prior to drilling and fastening. Small adjustments in the position of the sheet makes a big difference in how flat it lies on the ribs and these clamps make those small adjustments quick and easy to make. A couple of big ones also make quick work of fastening the ribs to the spars. A debate raged on the list a while back about the necessity of a pneumatic rivit gun. My opinion is that if you're building a basic kit with the sailcloth wings and few other add ons, you probably don't need the gun. But with the Stits process wings, fuggedaboudit. Buy the tool. Get both, though; there are lots of times and places the hand tool is the one you want to use - like when you want to apply slow controlled pressure to drawing the rivit or when working in a tight spot.







On Don Zank's advice, I cut the rootend top and bottom sheeting in half to a width of three inches to save some weight and material. Even so I had to order a couple of extra pieces of sheeting when I mistakenly cut too many pieces to the shorter bottom length; this stuff doesn't stretch too easily... But I've since found that it's really useful to have this sheet stock around for other aspects of the project. I've used it for additional bracing for the fuel tank box, the nav light mounts, all sorts of things. Mistakes often seem to have a way of being useful in some other way. Of course it's easy to keep that perspective as long as the part I've ruined isn't too expensive. Education is seldom cheap.







Here's a jig I made up to hold the aileron in it's correct position relative to the wing frame while drilling holes for the aileron hinges. Both the wing and the aileron frames are on a flat surface. Hinge positions have been marked on the wing rear spar per the drawings and the hinges have been temporarily fastened to the wing spar with two aluminum rivits. I did find that the hinge spacing in the manual will land one of the middle hinges on top of an aileron rib. Apparently with the changes in aileron design over the years, the manual hasn't gotten updated. Just move the hinge a bit. I then placed a length of 1" square steel tube (at 'A' in the photo) across the front and rear wing spars beside each of the four hinges. 'B' in the photo is a scrap of 1/8" thick aluminum stock clamped between the square tube and the aileron leading edge tube. The trailing edge tube of the aileron is flat on the work surface (this will position the aileron in a slightly downwardly deflected position). The aileron is then positioned against the hinges on the wing spar; it can still be moved because the square tubes are not clamped to the wing - they're just lying across the spars. When everything is lined up accurately, the aileron centerline should line up with the hinge pin as specified on the drawing and the surface of the aileron will be 1/8" below the surface of the wing. Clamp the aileron to the hinge with a couple of big spring clamps as at 'C'. With a marker, outline the hinge position on the aileron leading edge tube so you can check for any movement of the pieces in the following steps. Release the clamps holding the square tube to the aileron and remove the the tubes and spacers. Next you need to deflect the aileron downward to open the hinges enough to be able to drill for the hinge rivits. You can do this by blocking up the trailing edge of the wing. Check to make sure the hinges havn't shifted out of position, drill and fasten temporarily with two aluminum rivits as on the wing. Remove all clamps and check aileron deflection. Using this method I got more than 30 degrees both up and down. Finish drilling all the rest of the holes then drill out the rivits to proceed with covering. This is a lot of words; doing it takes less time than writing it.








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