HID Landing Light
HID has two advantages:
- It produces a great deal more light (around 10x the photons)
- It draws a great deal less electricity. (approx 3 amps)
The downsides are:
- It takes about 5 seconds from the time the switch is thrown until it reaches full brightness (a non-issue in some's estimation for some purposes)
- You have the extra weight of the ballast. Extra weight is never a good thing on an aircraft. The ballast weighs 4-5 ounces.
- HID requires high voltage (15K-20K volts) to ignite. During ignition (5-10) seconds, the high voltage can create radio noise
- Builders really want an installation that does not require modification of the current landing light. It should just “drop in”
- Current Aviation HID systems that would “drop in” run in the $300-$500 range. This page describes a project to deliver the same quality for significantly less.
Automotive HID systems are very durable and should perform well in our aircraft. Life expectancy on the bulbs is around 3000 hours (lifetime of the aircraft). They handle shock and vibration well.
The factory incandescent is a 100W PAR-36. Parabolic Aluminized Reflector, 36 eights of an inch in diameter. It is a focused beam with a dispersion somewhere in the neighborhood of 10 degrees horizontal and 10 degrees vertical. Essentially it is a spot light, not a flood light.
HID Bulbs/Systems come in a lot of flavors. A quick search of the net will turn up cheap halogen to HID conversion kits. You can get two bulbs, two ballasts, and two wiring harnesses for around $110. You will see them listed as: H1/H3/H4/H7/H11/H13/9005/9006/9007 These are bulb types. For the most part, a ballast will drive any one of the types.
One of the bulbs might look like this:
There are two flavors of conversion kits. Cheap flavor mentioned above and expensive flavor (no middle). The expensive conversion kits run in the $300-$500 range.
The cheap systems above (H1/H3/H4/H7/H11/H13/9005/9006/9007) can be produced cheaply because they build the igniter into the ballast. Lower parts count and all that. The downside is that it makes them EMI noisy.
The expensive systems used bulbs D1S/D1R/D2S/D2R/D3S/D3R/D4S/D4R. These “D” system have moved the igniter to a small module that joins directly with the bulb. It looks like this:
D1S on left, D1R on right. Notice the clip on the “R” (it looks like it could be easily removed)
The name of the bulb has some significance: Letter “D”, Number (1-4), followed by S or R.
“D” means Dual Pole. Look closely at the bulb. It has two compartments. It also has the rod coming from the base of the bulb and attaching at the top. 1-4 refers to the gas used (Mercury, Xenon, etc.). Actually, if you want to talk tech, it is called a “Capsule” "S" is Straight, or Standard, R is Reflective or Reflector. “R” type Capsules will have a metal band around the base that blocks light. It is intended to keep high beams from overlapping the low beam and causing glare. I’m not sure, but the metal band on the “R” might be a clip that can just be pulled off???
D series don’t have the high voltage line from the ballast to the bulb. This makes them is noise free and expensive.
If you look up XeVision at http://www.xevision.com/ Look for the landing light conversion kit. They use a D1S bulb and they want $499 for the 35W version. For one light.
You might also see “digital ballast” advertised. By using a computer to control the ballast, it is possible to bring the light online a little faster and shut it down in such a way as to extend the bulb life a bit. For this project, the ignite time is not an issue, and the bulb lifetime is already comparable to the airframe lifetime, so it would seem that digital balast is not a necessary expense.
If you look on the eBay, you will find complete systems with two of everything (removed from automotive) for under $200. You can probably find another builder to split the set with you.
These systems can be found on the Internet and in salvage yards. If the bulb type is not known, look to see if the igniter is attached to the bulb. If it is, you should be good-to-go.
I purchased my system on ebay. Check out this store: http://myworld.ebay.com/allstarautosalvage
They sell salvaged headlight units. Many have a broken tab or a cracked enclosure. I didn’t need the headlight, I wanted the guts. He lists the headlight by make, model and year. It is important that it is listed as “HID/Xenon components included”; they aren’t always. I found a Corvette headlight, 2001-2005 with the goodies; lower mounting tab was broken. A little more research and I confirmed the high beam for that model/year was a D1S HID.
I bought the thing and had it for $39; including shipping. Everything worked like a champ. They were quality OSRAM components
The part that is not so easy to find is the PAR-36 reflector with the focal dimension we need. I could not find a spot on XeVision’s site where you could just purchase the PAR-36.
Duckworks sells light upgrade kits for RVs. Their landing light is the same PAR-36 we use.
Don Wentz is the owner. Nice guy. He will sell you just the PAR-36, modified for the D1S HID. It was $53 delivered.
Don also has a very reasonable kit, with the D1S HID, ballast, cable and reflector for $290 (if you want to go that way)
It has a special machined fitting on the back to hold the igniter. It is a very nice piece. This is what my installation looks like.
Retract guys will need to do some extra work. I believe the nose gear comes very close to the landing light and it could interfere with the igniter. Another good reason to get fixed gear.
With a little looking and some patience, I have an HID photon cannon for around $100. The sucker is VERY bright. I fired it up and it was like Rudolph. People were shielding their eyes and telling me to “turn that thing down.” In the plane, there is so much light that the nose glows; at least until I get some paint on it.