Headlights

[Lou]

I'm in the middle of assembling my wings on a wooden airplane, any
reason I can't use hologen car headlights in the leading edge?
Lou

[RST Engineering]

Halogens run hotter than standard incandescents. You may want to test to
see how hot they really get (after you forget to turn them off for half an
hour after departure). That's what I would concern myself with a wood
structure.

Jim


"Bryan Martin" > wrote in message
...
> No reason I can think of, go for it.
>
> in article om, Lou at
> wrote on 8/21/05 4:09 PM:
>
>> I'm in the middle of assembling my wings on a wooden airplane, any
>> reason I can't use hologen car headlights in the leading edge?
>> Lou
>>
>

[Lou]

This was also my concern, I was hoping someone has allready done this.
Thanks
lou

[Ernest Christley]

Lou wrote:
> I'm in the middle of assembling my wings on a wooden airplane, any
> reason I can't use hologen car headlights in the leading edge?
> Lou
>

That's what I'm using, Lou. Bought a set of aftermarket fog light at
Wal-Mart. I'll be attaching one to my nosewheel. If I don't see the
light at night, it'll be a clear signal that I need to extend the retracts.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

[Morgans]

"RST Engineering" > wrote in message
...
> Halogens run hotter than standard incandescents. You may want to test to
> see how hot they really get (after you forget to turn them off for half an
> hour after departure). That's what I would concern myself with a wood
> structure.

Yep, me too. Also, if you use a standard rectangle headlight, they are
heavy, and you will need to make an adjustable mount.

Think about the driving light type of halogen. They have a nice narrow
beam. Also, how about doing like some of the old-time planes, and making it
flip down out of the bottom of the wing. That would be cool, huh?
--
Jim in NC

[Dan, U.S. Air Force, retired]

Ernest Christley wrote:

> Lou wrote:
>
>> I'm in the middle of assembling my wings on a wooden airplane, any
>> reason I can't use hologen car headlights in the leading edge?
>> Lou
>>
>
> That's what I'm using, Lou. Bought a set of aftermarket fog light at
> Wal-Mart. I'll be attaching one to my nosewheel. If I don't see the
> light at night, it'll be a clear signal that I need to extend the retracts.
>


An audible warning would be the sound of the prop striking the ground.

Dan, U.S. Air Force, retired

[jerry wass]

I Would use one of the little "muffin fans" available from surplus
stores, electronic supply stores, etc. get a 2 or 3" fan and duct it
so that you get good cooling of the bulb--there are lots of light wt.
headlight assys. on the newer autos, and you can find a little peanut
sized halogens up to 100 watts--but you need good connections and
probably a glass lens (too hot for plastic in my opinion)---Jerry
Lou wrote:

> I'm in the middle of assembling my wings on a wooden airplane, any
> reason I can't use hologen car headlights in the leading edge?
> Lou
>

[Rich S.]

"Morgans" > wrote in message
...
>
> Think about the driving light type of halogen. They have a nice narrow
> beam. Also, how about doing like some of the old-time planes, and making
> it
> flip down out of the bottom of the wing. That would be cool, huh?

I have a pair of those from Harbor Freight. Gonna mount them in the aluminum
gear leg fairings with one of Jim's flashers for anti-collision.

Rich S.

[Lou]

Actually, the Harbor Freight lights are top of the list, have you
plugged them in to test for heat?

[Rich S.]

"Lou" > wrote in message
oups.com...
> Actually, the Harbor Freight lights are top of the list, have you
> plugged them in to test for heat?
>

No, they're still in the box (five years after I bought them). In my case,
they would be mounting to the landing gear leg (2½" 4130 steel tube) and be
faired with .020" aluminum, so heat wouldn't be too much of a factor. Being
in the airstream would keep them cooler than being enclosed in the wing.

I have two regular aircraft landing lights in the left wing under a
Plexiglas® cover and have not had a heat problem there. I wish I had made
two independently adjustable mounts so one could be aligned for taxi and the
other for landing. Actually, since I don't fly at night any more, I should
take them out and make an evaporative beer cooler out of the housing.

Rich S.

[Ron Natalie]

Lou wrote:
> I'm in the middle of assembling my wings on a wooden airplane, any
> reason I can't use hologen car headlights in the leading edge?
> Lou
>
Jackie Yoder had car headlights in his leading edge. The only
tricky thing was bending the lenses. We went to great lengths
describing building the oven he used to heat up the acrylic.

[RST Engineering]

And being in the airstream is going to make them popcorn during rain or snow
hitting the hot bulb.

Jim



"Rich S." > wrote in message
...

.. Being
> in the airstream would keep them cooler than being enclosed in the wing.

[ORVAL FAIRAIRN]

In article >,
Ron Natalie > wrote:

> Lou wrote:
> > I'm in the middle of assembling my wings on a wooden airplane, any
> > reason I can't use hologen car headlights in the leading edge?
> > Lou
> >
> Jackie Yoder had car headlights in his leading edge. The only
> tricky thing was bending the lenses. We went to great lengths
> describing building the oven he used to heat up the acrylic.


I made copies of both sides of the LE of the wing out of plywood, formed
an aluminum sheet between them and covered it with thin felt and used an
oven set at (350(?). -- whatever Rohm & Haas recommends. Works like a
charm!

[[email protected]]

Lou wrote:
>
> I'm in the middle of assembling my wings on a wooden airplane, any
> reason I can't use hologen car headlights in the leading edge?
>

Energy is conserved. All of the energy used by a light
becomes heat. The energy that does not become light,
becomes heat locally.

So if you can find the efficiency of the type of light you
are using, subtract that number from one and mulitply that
differance by the wattage for the light. That will tell you
how much heat is going to be dissipated by the light.

E.g:

q = (1 - e)P

That won't tell you the surface temperature of the light,
but it will give you a means of comparing different lights.

E.g. a 1000 watt light operating at 5% efficiency will
dissipate as much heat as a 500 watt light operating at
10% efficiency. If the first has about twice the surface
area of the second then as a first guess they will both
have about the same surface temperature if housed in
similar environments.

BTW, weren't halogen bulbs originally developed for aircraft
landing lights?

--

FF

[Rich S.]

"RST Engineering" > wrote in message
...
> And being in the airstream is going to make them popcorn during rain or
> snow hitting the hot bulb.

Rain? Snow?? Flying???

Bwahahahaha.

Rich S.

[Lou]

I didn't realize there was a test involved. I thought I would just make
a mock up enclosure with a thermometer probe inside.
Lou

[Morgans]

"Rich S." > wrote

> I have a pair of those from Harbor Freight. Gonna mount them in the
aluminum
> gear leg fairings with one of Jim's flashers for anti-collision.

Two thoughts, (rather questions) on the subject.

Don't they have a pretty slow heat up, cool down time? If the answer is
yes, they would not be as recognizable as something that had an instant off
(dark), instant on (bright) cycle - like LED's, would they? Or is that not
a big factor?

Is the quartz halogen evaporation, condensation cycle a problem in terms of
short burn out time, when it is cycled on and off, without time to stay hot?
I have no idea, just a question. Are they commonly used with flashers
without problem?

Putting them in gear fairings does seem like a good idea, though.
--
Jim in NC

[Morgans]

"RST Engineering" > wrote in message
...
> And being in the airstream is going to make them popcorn during rain or
snow
> hitting the hot bulb.

Kinda like how that happens all of the time while they are on cars?

Jim, Jim, Jim.... <g>

*Most* people put those kind of bulbs in front of a reflector, and behind a
lense?
--
Jim in NC

[Morgans]

"Ron Natalie" > wrote

> Jackie Yoder had car headlights in his leading edge. The only
> tricky thing was bending the lenses. We went to great lengths
> describing building the oven he used to heat up the acrylic.

Do you know if he had the area opened up to the rest of the surrounding wing
(for dissipating the heat), or had some airflow going to the area, or some
other trick to keep the wing and plexi cool?
--
Jim in NC

[Rich S.]

"Morgans" > wrote in message
...
>
> Don't they have a pretty slow heat up, cool down time? If the answer is
> yes, they would not be as recognizable as something that had an instant
> off
> (dark), instant on (bright) cycle - like LED's, would they? Or is that
> not
> a big factor?

I remember flying the Adcock (A-N) range from Yakima to Ellensburg one day
in my Dad's Cessna 120. Something made me look up and I saw a C-124 coming
straight at me about ¼ mile away. All I remember is his anti-collision light
flashing in my eyes. That light was an oscillating beam like a train
headlight of the era. It didn't have the instant off/on quality of a strobe
or an LED, but it sureintheheck got my attention RFN!

Jim has published a lot of dope on flashers for anticollision purposes.
IIRC, he not only takes the properties of the device into consideration but
also the properties of the H.U.M.A.N. interface system. If I ever get around
to putting this together, I look it up.

Than again, I might be wrong. In that case, never mind.

Rich S.

[Bruce A. Frank]

Lou wrote:

> I'm in the middle of assembling my wings on a wooden airplane, any
> reason I can't use hologen car headlights in the leading edge?
> Lou

OK, I have read several of the responses. There is a lot of difference
in halogen running lights, the kind you mount on the bumper or on a
light bar on top of your truck, and halogen headlights. The running or
off-road lights are usually small and designed to stay cool by being
mounted out in the air. They get HOT and don't work well when mounted
inside enclosures...where they may melt the insulation off their own
wires.

Halogen headlights these days are, in many cases, a plastic unit with
built in reflector and lens. The halogen bulb plugs into the rear. The
size of the reflector/lens housing dissipates the heat very well and
lights left on for hours with the vehicle sitting still have no problems
with meltdown. If you choose to use a complete headlight from a salvage
yard there will really be no problems in that leading edge position.
Leave the headlamp and housing intact and add a curved, leading edge
shaped Plexiglas lens in front of it. The draw back may be the physical
size of the headlamp will be such that it will not fit in the space
between the spar and leading edge. Mounting it out towards the tip of
the wing may put it in a position where cutting a hole in the spar to
allow for enough setback would cause no structural problems.

If you go with one of the running light/fog light types you will need to
build a metal box around it (not sealed up...just sides, top and back
plates screwed or tack welded together to reflect the heat.) and maybe
add a blast tube from a wing root air intake source. A plexi leading
lens will have no problem handling the heat if the lamp itself is kept
back a few inches (4 to 6 or so) from the lens itself.
--
Bruce A. Frank
======================
Aircraft Projects
Fuel Tank Fabrication
For Homebuilt Aircraft, Antique Fuel Tank Repair
TIG, MIG & Oxy/Acet Welding & Brazing

[Don Hammer]

Big aircraft like Gulfstreams etc route ram air to cool the enclosed
landing lights through a piccolo tube. Because you need forward speed
there is a time restriction using them on the ground. Taxi lights are
on the gear so they don't need to cool them

[Lou]

That makes sense, but I'm curious of 2 things. Do you need an exit for
the air?
Is there a screening material to keep bug from nesting while not in
use?
Lou

[[email protected]]

On 23 Aug 2005 19:17:01 -0700, "Lou" > wrote:

>That makes sense, but I'm curious of 2 things. Do you need an exit for
>the air?
>Is there a screening material to keep bug from nesting while not in
>use?
> Lou
yes and yes.

[Don Hammer]

Like he said yes and yes.

Some aircraft have a vent hole on the LE. The tube makes a turn to
get rid of the rain etc then dumps into the LE and departs eventually
where the wing de-ice hot air goes. Others get the air from the
pnumatic system of the aircraft so it is already bug and water free
and cools on the ground. Kind of hard to do that on a recip though.