)So, doing a little research came up with the following idea: Instead of spending $1K on an alternator I could spend it on Whelen L.E.D. Nav/Strobe system. http://www.aircraftspruce.com/catalog/e ... 105648.php
(Hint-Hint for you guys about to put on wingtip strobes....the LED system is only a couple bucks more than the standard and you'll save the difference the first time you don't have to buy a replacement nav-lamp at $18 each.) L.E.D.'s will last almost as long as the pyramids of Giza and use 1/10th the electricity of ordinary nav lamps.
As an EXPERIMENT ONLY (heh-heh...you guys who wonder if I'd ever do anything slightly illegal are gonna love this) I ordered some automotive 1156 L.E.D. replacement bulbs. They are advertised as direct replacements for 1156 incandescent lamps and have 39 LED's in them, 18 forward-firing and 21 side-firing. I made a comparison in the darkened hangar. The LED's are actually much brighter when viewed directly than incandescent bulbs. (I didn't have a LUX meter but I'll bet any photographer could measure it with his meter.) The savings is slightly more than 5-Amps when replacing all three std nav lamps, for a 15% reduction in generator-load using a 35 Amp gen. It's like converting my 35 Amp to a 40 Amp generator for the price of bulbs. (Poor analogy, actually it's my 35A gen having 5 Amps less work to do.)
The individual LED bulbs cost about the same as std Whelen nav lamps, but generate virtually NO HEAT, consume only 2.4 watts (.173 Amps @ 13.8 volts) for a savings of 23.6 watts per bulb. (5.5 Amps total)
I came back into the house from looking at the LEDs and it took almost 20 minutes before my eyes recovered from the burn-out spots sufficiently so I could read again in normal light.
Now, to be accurate, ... being automotive, they are not certified to meet FAA requirements for candlepower or color. But my eyes can't tell the difference in overall effect except that the LED's, when viewed straight-on, are somewhat brighter, in my opinion.* (And the white, tail-nav-lite is a brighter/crisper...(cooler?) white...as opposed to the "warm" white of an incandescent bulb.) <SUBSEQUENT EDIT> Advisory Circular AC 23-27 allows the use of automotive equivalent parts on aircraft mfr'd prior to January 1971. LED lamps seemingly identical to these I installed are also offered by Spruce as "Standard Parts", meaning they may be used on certificated airplanes as direct replacement parts. Since the source I mention in this article is half the price of the Spruce 1156/1157-type LEDs... I have retained the ones described in this thread on my airplane. It is now 2 yrs later and they still work just perfectly.)
* Addendum: (Later, when my eyes recovered, I realized that the "super"-white LED bulbs, when filtered thru the red and green lenses of the nav light fixtures actually had a slightly orange-ish and blue-ish color-shift to them. This is corrected by installing red and green LEDs which are color-corrected automatically, and have the added advantage of not losing as much brilliance by having so much of the white spectrum removed by the colored lens of the nav light fixture.) Possibly workable red/green substitutes are: http://www.ledlight.com/s25-36-super-br ... light.aspx and/or http://www.ledlight.com/s25-32-led-light.aspx
http://www.ledlight.com/s25-39-led-light.aspx
PS- One must grind one of the tabs off the bulb-base so it'll fit a standard nav-light base, due to the 1156 base, but otherwise it's a perfect fit. It fits the tail-nav light fixture without modification because an automotive 1156 bulb will fit back there just fine, also.
Now,... don't go waste your time and money for bulbs and shipping if you think you're gonna replace your interior #67 lamps (the std C-170 instrument lamp) in those original Grimes "torpedo" fixtures because that won't work. The #67/89 LED replacements (shown below) are forward-firing only and the lamps in those Grimes torpedos utilize the side-illumination capability of standard incandescent bulbs. So the LED versions won't do "squat" in those applications, even tho' when viewed directly you'll think the sheriff has pulled you over and decided to spot-light your eyes and burn-out your retinas. (I was hoping different, but they just don't work well in that particular Grimes fixture.)
Addendum #2: Keep reading, Dear Reader, where on pg 2 of this thread you will see how the interior lights were dealt with and how I was successful at replacing all the #67 lamps as well with LEDs.
May there always be and Angel flying with you.
Respectfully, Doug
