On Sat, 14 Dec 2019 19:57:20 -0500, wrote:

On Sat, 14 Dec 2019 16:50:03 -0500, Clare Snyder
wrote:

On Sat, 14 Dec 2019 13:58:52 -0500, wrote:

On Sat, 14 Dec 2019 08:50:03 -0800 (PST), trader_4
wrote:



The contradiction is that the US had sealed beams because the govt claimed
the design with separate lens, bulb and reflector were prone to degradation,
dirt, misalignment, which would reduce visibility.

That is all still true and to say they can't enhance the ability of an
industry standard sealed beam instead of that plastic piece of ****
that is model proprietary even among similar cars from the same
manufacturer in the same year is ludicrous. There may be some small
aerodynamic advantage to the new style lights but it is mostly just
"style". I also disagree that they would cost more than $5 if it was
a commodity part that spanned several hundred million cars. The
Chinese would be pounding them out for pennies a unit.


The aerodynamics are significant

Define significant. 0.5% difference in MPG on the interstate? Most
driving is 30-40 MPH around town and aerodynamics are insignificant at
that speed.

and if the Chinese pound them out
for pennies a unit they will have the same problems the aero
headlights do.

If they used a common, simple shape, they could be Pyrex again. Tough,
scratch resistant and UV immune.

Then you go on and make that case.

The problem is the plastics they are using, not the design. It needs
to be UV resistant, chemical resistant, ozone resistant, high impact
resistant, optically clear and reasonably priced. Oh yes - one more
thing - it needs to be economical and easily molded and fabricated.
Polycorbonate hits every base except UV resistence.
Lucite (acrylic) solves the UV problem but is brittle and gets soft
with heat - high output headlights have melted lucite lens.
Coextruded plastics with acrylic top surface over polycarbonate are an
option - not sure how they would stand up if the acrylic doesn't
filter out the UV.

Boric glass or lead crystal hit all the bases except price (and weight
which I did not mention).

Not much else out there.
They could be pyrex today too - it would just add a few lbs and a
couple hundred bucks to the MSRP