GE Q4681 Bulb Overview
Have a client that is getting really tired of GE Q4681 28 Vdc sealed beam headlamps. Would prefer a longer life bulb, was thinking of changing out the whole assembly. Need the same lumins, but as measured in the visual bandpass. Need 28 Vdc (+3/-10) operational capability (though does not need to maintain intensity outside 28 Vdc). Ergo likely need some type of electronic power supply to go with the LED bulb. Specs on the bulb would be same diameter, OK to go deeper, OK to have eifferent connector, needs accompanying schematic and suggested parts list for any power supply required.
The GE Q4681 appears to have a very short life expectancy rating, of only 50 hours. Another huge disadvantage of this light is the tremendous current draw, which can be hard on the alternator and other aspects of the electrical system. It also means significant heat generation as well. The light does appear to have a very powerful photometric beam, rated at 310,000 candelas. With most of these GE PAR bulbs, the maximum candela rating refers only to the inner beam. You would probably not see this maximum candela rating over the full beam angle of 15 degrees, but rather from a smaller portion near the center of the beam. It is the narrow center beam, close to 3 degrees, that really provides 310,000 cd. One of the common known problems with this bulb technology is the filament is very prone to damage from repetitive vibrations. Further more, the integrated mounting tab forces the bulb to be mounted in such a position that the filament sits parallel to the horizon. This position can lead to additional induced stress due to a droop affect. Each aircraft landing will stretch the filament creating additional stress, and eventually failure.
LED Replacement for GE Bulb
Lunar Accents Design is currently in the final stages of development on a GE PAR replacement bulb. Our bulb will be FAA approved for use on any aircraft listed on our approved model list. The integrated power supply will provide the required current and voltage to each LED, thus no external power supply would be required. LEDs offer a lifespan much greater than that of the original GE bulb, and do not contain vibration sensitive components. Due to the nature of this project, we cannot provide specifications prior to the scheduled release date of the product. However, we can guarantee the performance will match or surpass that of certain GE aircraft landing lights, and will offer a life expectancy much greater than any aircraft landing light currently on the market. We firmly believe our LED aircraft landing light will set the standard for many LED landing lights to follow.