29 Oct 00 first draft Panel End Rib Installation -------------------------- The panel end ribs require great care in installation. The four end-rib/spar joints transfer all torsion loads between panels. Failure of any of these joints during hard winching or a high-speed dive will likely result in destruction of the glider. Rough up the Kevlar wrap all around the spar where the end rib and its gusset is attached. Glue these on with a good slow epoxy. Fill any gaps with thickened epoxy. See "Glassing End Ribs" for further work on this joint. Trailing Edge Installation -------------------------- Notch the TE strips with a ~6 in piece of ~1 x 3/32 hard balsa, with 150 grit sandpaper glued to one edge. Cut the sandpaper edge strip to an accurate 3/32 width with a straightedge and razor blade. Sand the side of this sanding block until the notches it produces give a light friction fit with the ribs. Glue on a hard 1/16 depth-gauge strip to the block, about 3/32 from the sandpaper edge (i.e. the notches are about 3/32 deep). Position the notched TE strip on the plan and trim all the ribs to the exact length to fit the notches. Put a healthy blob of Titebond in each notch, and work the strip onto the ends of the ribs. Make absolutely sure each rib is seated flush with the bottom surface (lift the panel to check). An unseated rib will put an unsightly glitch in the bottom covering. Wipe off oozed out Titebond, but leave some as generous fillets in all corners. Leading Edge Installation ------------------------- The bottom edge of the inner LE strip must be bevelled before it is glued to the ribs. The "Accurate Shaping..." info sheet shows how to sand the edge at the correct slope. See the wing_plan.pdf drawing for the required bevel slopes. Bevel the edge of a 3/32 sheet first, and then cut the strip off with a straightedge and razor or X-acto. Bevel the front tip of each rib to match the LE sweep. Glue the LE strip onto the ribs, making absolutely sure it is flush with the bottom of each rib. Turn the wing over if that helps. Using Titebond allows the strip position to be adjusted before it sets. It is not necessary to bevel the bottom of the outer LE strip before installation, but it considerably simplifies accurate final shaping of the LE. Glassing End Ribs ----------------- Bevel the side of each end rib to the required 6 degree angle. Apply 2 layers of 1.5oz or 2.0oz glass to the top and bottom of the end ribs. Carry the glass over the spar as shown on spar_plan.pdf. Put microballoons/epoxy on the spar if necessary to get the glass to lie smoothly and without any voids under it. This glass is crucial to prevent the joint from peeling apart under load. Rear Support Strip Installation (can be done after sheeting D-tube) ------------------------------- For each panel, cut a tapering strip from 3/32 sheet, with widths shown on the wing_plan.pdf drawing. Cut each segment by placing one end of the long strip against a rib, and nicking it at the other rib. Cut at the nick or very slightly outside, and sand the end of the strip segment to a perfect friction fit between the ribs. Leave it in position and continue with the next strip segment. Glue all the segments by removing each one, applying Titebond to the strip and rib, and replacing. Sight down the panel to align them perfectly (a wavy strip line is unsightly). Raise them all slightly above the ribs, and push them back down flush with the ribs using a straightedge. Wipe off all Titebond beads, leaving generous fillets. Use this same nick-and-cut method to install the spoiler well strips in the center panel. The triangle strip at the spoiler hinge is installed beforehand.