Moving Landing Light: My slow-build wings have gone slower...

Andy_RR · #1 07-15-2010, 05:06 AM

...due to my reinventing the leading edge lighting!

I've been keen on pitch-adjustable lighting to enable each lamp unit to double as landing and taxi lights (taildragger), so to this end I've designed and manufactured a new light bracket to accomodate the Planelights.com MR16 35W lamps. I've chosen to have a single lamp each side, one being fixed and the other pitch adjustable by a servo.

I spent some time CAD-ing up a nice round leading edge aperture that accomodates the appropriate pitch and beam cone angle, along with my idea of a bracket

I had fun and discovery converting it all to flat patterns for CNC cutting

Here's the bracket,

...and the aperture,

...and the whole caboodle under bench test,

...giving the following results:

I then used the aperture template to cut the vinyl off the leading edge - checking visually for symmetry...

...followed by a nerve-wracking cutting of the leading edge and a trial installation of the whole shooting match

Initially, I used the Duckworks/Van's-sourced lens cut in half, but I was less than happy with the way it fitted the profile of the leading edge, so I remanufactured my own lens in 2mm perspex, heating a 250mm x 90mm sheet to 150°C and draping it around the outside of the wing. The fit is much improved!

The bracket is located by three pull-rods (manufactured from Al welding wire, threaded each end M2.5)...

two going back to the pitch control servo (or holes in the spar for the fixed lamp)...

and a third span-wise link to give it some rigidity in that axis. This one is located by a rubber grommet, washers and adjusting nuts.

In my design I've tried to keep it light weight and to keep what weight I do put in as far inboard as I dare. I have strapped the HID igniter/ballast/controller to the spar in the next inboard bay, although I dared not move the actual lamp (and aperture) further inboard. As it is, it is as far inboard as working through the lightening holes will permit, save Mr Tickle around to help or employing dwarfs and midgets to crawl inside for repair.

The servo is an Hyperion programmable aileron servo and my intention was to have it swing between two pre-programmed positions by switching the signal line high/low. Ambition has got the better of me, so now my plan is to design a black-box that intercepts the pitch information on the (intended) Skyview data bus and convert it into a PWM signal so I can make it auto-levelling (to stop blinding on-coming aircraft on the approach path, of course!) We'll see how this bit progresses. Maybe Dynon will pre-empt me and get Skyview to have programmable PWM signal channels for "various things"?

So that's it for now!

I will get my motivation going to open the can of proseal soon...

Andrew

RV-8 (wings)

gereed75 · #2 07-15-2010, 10:07 AM

Really Nice job! I have often thought about doing this and that the easy way would be to pull the tilt mechanism out of an automobile adjustable side mirror. The servo motors, limit switches, wiring and control switch are all there, already engineered and packaged in a neat little adaptable package running on 12V. Perfect. And available at the local junk yard. Never did it though - found a pretty good compromise angle that gets the runway during approach and gives a bit of light while taxiing.

Isnt it amazing how much time these little mod/engineering projects eat up!!

Still thinking about how to use the slick little linear accuators that open and close the rear window wing vents in my 3 series BMW - rudder trim maybe. Naw, already made that with a sunroof motor out of a Mazda. Works like a champ!!