Headlights

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.

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.

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!

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

"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.

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

"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

"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

"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

"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.