Single Landing Light Flasher? (not wing wag)

[rzbill]

The situation of flashing a single 100 watt bulb was handled many years ago in the motorcycle industry. A handful of manufacturers made a "box" to flash the high beam. Sorry, I can't spout off any names but a web search should give some answers.

Since I am a frugal sort, I built my own (they were wanting $100 for them in 1980). It is a simple circuit using an NE555 timer chip to drive a Darlington paired transistor that can handle 10 amps (I have a 75 watt halogen bulb). The Darlington must be mounted on a heat sink. (I potted the first unit and it melted)

**EDIT** I was talking to my Dad about this e-mail (he helped me build my original MC flasher back in the 80's) and he said we probably should have used a field effect transistor (FET) instead of the darlington pair. The FET has much lower "on" resistance and will create less heat in use. **

4Hz is the fastest you can practically drive a halogen headlight. At 8Hz, the light no linger appears to blink due to persistance of vision and cooling physics of the bulb filament.

Anyway, I have more than 1000 hrs on it (70,000 road miles). Original bulb too.

Since I have no radio on the motorcycle, I cannot say how this fluctuation in current would affect radio systems in an aircraft, but I have never noticed any noise in a car radio that was in proximity.