A tinkerers Toys

[HighWing]

Post Number 5.
When I began this project, there was an article in Kitplanes by the electronics guru, Jim Weir. In it he explained the electrical needs of LED bulbs and explained that for constant light output they needed constant current rather than a set voltage. He then offered a power supply in schematic form. I was hooked. When I finished my first one, I was surprised how large it was. Later experience with DC to DC voltage converters proved the concept. To change from 12 V. to the voltage needed for a typical LED required first conversion to AC to feed a transformer, then back to DC at the new voltage. Without adequate filtering, these can be really noisy. Flying under Sport Pilot, I really didn’t need the lights, but wanted them just in case.
The first pictures will show how I mounted the aft position lights. To avoid complexity, at least so I thought, I decided to position them on both sides of the rudder so there wouldn’t be a possibility of rudder shadowing. For that I needed some custom lenses. The lenses were made using a vacuum forming technique I learned in the dental office – Mouth guards and bleaching trays. No longer having the equipment, but knowing how it worked meant searching for components and building my own.

The lights on the wing tips used the same mounting method that I used on 96KL, but using the LEDs rather than the big bulbs. While working at United Airlines as a fueler, I noticed on the B-727s they had an interesting wing tip design that I adapted to the Kitfox. A “door” was cut out of the fiberglass. Then a lip was added to provide positive positioning with screws into nut plates for attachment. A lens was fabricated using heated Lexan forced over a plug made from the wing tip for shape. This was then glued to the “door”. A note on heat forming Lexan (Polycarbonate). A quirk of the material is that it is extremely hydrophilic – it absorbs significant quantities of water. To heat form it successfully, it needs to be dried in an oven for a time determined by its thickness. Otherwise it will look really interesting after forming - lots of steam bubbles within the plastic - large and small.