Construction Details - Tail Feathers




Filing off the edges and corners of the gussets on the tail feathers. I'm holding a piece of aluminum flashing under the edges and corners of the gusset to keep the file from cutting into the tubing. The open end of the tubing that is facing you in the photo has been ground back or 'fishmouthed' to match the curvature of the intersecting tubing. I initially thought that the fabric would span the open end of the tube while following this curve when it was shrunk thus making for a smoother appearance. But this turned out not to be true; it was ugly. I should have tried it out on a test sample before doing it to every open tube end on the tail feathers. Arghh... More on this later.







Marking the centerline of the elevator frame in preparation for drilling for the hinges. Frame flat on the bench, carpenter's chalk rubbed on the frame, combination square scraped along the frame. Subsequently, I realized the chalk was superfluous as the square would scrape a bright line on the oxidized surface of the tubing.







Kuntzleman strobes will be installed on the tail fin and belly. The Kuntzlemans were chosen for their low current draw. The mounting plate shown in the photo is pre-formed to fit a smaller diameter tubing than the Challenger tail fin frame. Warming the plate gently with a heat gun makes it pliable. It's then pressed against the frame tubing and forms to the larger radius. You may be able to see that the top surface distorts as a result of this operation and needs to be flattened after forming. I did this by carefully holding the top of the fitting against an inverted belt sander. I decided to fasten the strobe mounting plate to the frame before covering so that the fabric would fair around it with no gaps or open joints. Here, the frame is being drilled prior to fastening the mounting plate.






Placing a rubber grommet in the hole in the frame through which the wiring will pass. The wiring was then run through the frame and the mounting plate before fastening the plate to the frame with epoxy and sheet metal screws. The wire was routed down the leading edge tube of the tail fin frame and was brought out through a hole drilled in the side of the mounting tube on the fuselage.










Back To The Index