I fabricated .063 2024-T3 doublers to mount the Aeroflash Nav/Strobe lights with the same dimensions as the base of the units. Only two front screw holes were usable on the Aeroflash units, so I drilled an additional aft screw hole for greater fastening security. I attached the doublers provisionally using sheet metal screws to the wingtips at the wingtips widest point (slighly aft of the front spar), and used a plumb line with the tips installed on the aircraft to make the doublers perpendicular to the ground. I then caulked the edges with RTV in order to have both a base for the doublers as well as provide a backstop for the fiberglass, and allowed the RTV to dry. I then trimmed the RTV and drilled the holes. I then epoxied two ply's of fiberglass and allowed that to harden. I then sanded the edges of the fiberglass smooth, and then followed 4 iterations of microballooning/sanding I also fabricated nutplated backing plates which will be glassed into place on the inside of the wingtips, and they will be seen in the Nav Light Fixture Wiring log.
Nav light bracket retained with #6 sheet metal screws over RTV base.
Holes drilled, fiberglass build up around bracket and RTV.
After contouring and smoothing with microballoons.
