Healsight bulb filament orientation

[david_dewey]

It's been a while since I messed with T headlights, and I searched but haven't found anything on this--I must have missed something! Helping a friend put his headlights together, new sockets, new bulbs. But we ended up with the filaments in a side-by-side orientation (vertical) instead of Hi-Low (horizontal).ff Checked his old ones to see if maybe we got the pre-17 sockets by accident, but they are the same orientation. Is this a flaw in the reproductions, or was Lo beam originally just aimed to the side of the road?
Thanks!!
David Dewey

[KWTownsend]

David
It's not so much as a high and low situation, but more of a "bright" and dim situation.

Depending upon the bulbs you use, your mileage may vary...

: ^ )

[Allan]

I understand from previous posts that the repop bulbs were made incorrectly
They need to be rotated 90 degrees to orient the filaments correctly.
High and low beams are a product of the correct alignment of the filaments in relation to the parabolic reflector in the lights. They do have different light intensities but it is the focus which gives the hi/low.

Allan from down under.

[Kaiser]

I always understood there was difference in orientation of the filaments (and thus the sockets) between magneto bulbs and bulbs for generator cars, possibly done to make it easy to see when you put in the wrong bulbs, as generator bulbs will quickly burn out in a magneto car because of the higher voltage a magneto can put out at higher revs.
From this follows that if you should put the right bulb in the right headlight, the filaments should be oriented horizontaly
Correct me if i am wrong, i start to question myself more and more these days, not getting any younger

[Jerry VanOoteghem]

Who can really believe that the beam will be appreciably higher or lower due to the tiny distance between the two filaments? Or, is that distance not so tiny?

[Allan]

Jerry, it has everything to do with the parabolic reflector. Shift the light source even a little bit, and that light will be reflected differently. More modern sealed beams were the same, two filaments with slightly different alignments.

It's also the reason multi LED could not be focused in T lights, because there were multi points of light being reflected. They may finally have fixed this by building globes with one LED and that one has its own built in reflector.

Allan from down under.

[TRDxB2]

The orientation of the filaments in the bulb being when at the focal point of a parabolic reflector have little or no practical relevance. The "focal point" or sweet spot of the reflector is actually very small. So when adjusting the headlights on Bright both filaments are illuminated and the brightest point is determined by the filament's light relationship to the sweet spot not their physical relationships.
Given the two bulbs below the filaments of the one on the left are tight together and almost form a square at the wire ends & bright and dim filaments are at the same height. If there is an argument on bulb orientation it would apply to this design of the bulb on the right with its filaments spread out and at different levels. Not much within the sweet spot.

bulb r.png (132.08 KiB) Viewed 1712 times

A two filament bulb which shines light onto a parabolic reflector and then through the lens into the area in front of the car. The parabolic reflector takes the light from the bulb and directs it parallel to the bulb’s axis in straight lines which means that the light is therefore organized (like a flashlight) and more useful than the scattered light of say a candle flame. The filament of the bulb will be positioned at the focus of the parabola making full use of the reflector to give the greatest light quantity. The parabola makes all the light waves nice and straight and organized and the lens can do its work to direct the light. The reason why these early cars had round headlamps was that it is the resulting shape for a parabolic reflector. The ribs on these headlamps’ lens’ aren’t for your pleasure they are called flutes, and it is their job to direct the light into the required direction. Nominally downward away from an oncoming driver’s eyes and to the off driver’s side direction.

[TRDxB2]

It's been a while since I messed with T headlights, and I searched but haven't found anything on this--I must have missed something! Helping a friend put his headlights together, new sockets, new bulbs. But we ended up with the filaments in a side-by-side orientation (vertical) instead of Hi-Low (horizontal).ff Checked his old ones to see if maybe we got the pre-17 sockets by accident, but they are the same orientation. Is this a flaw in the reproductions, or was Lo beam originally just aimed to the side of the road?
Thanks!!
David Dewey

It would help to see what headlight buckets you have as well as the sockets.
There are two variations of headlight buckets based on the focus screw position, twelve o'clock and 9 o'clock.

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Then there are variations of the original sockets to keep the bulb aligned (The original two filament bulbs as shown in my previous response are so close I can't see how orientation would cause a difference)
If you very close to these pictures you'll notice #1 is for the 9 o'clock bucket #1 and #2 socket is for the #2 bucket at 12 o'clock
An even closer look shows that the contacts are 90 degrees off but the cuts for the plug & bulb are in exactly the same position.

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Now there are some differences in the 90 degree plugs, but not the straight on. The one on the left is for the #2 socket & bucket.

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So if the "supplier" 90 degree plug was used in the #2 Headlight & socket its end would point to the left. However If a #1 socket is used in the #2 headlight bucket the supplier plug end would be pointed down but the filament position would be changed. Same is true for that combination for a straight through plug.

If this is the style bulb you are using there is no orientation affecting light focusing issues (right is rotated)

[Greg Griffin]

Original Ford-specified dual-filament headlight bulbs had one 21 candlepower (cp) filament for "on", and one 2 cp filament for "dim" (later 3 cp). The dim was a parking light, not "low beam" headlight. While 21 cp is not very bright by tod ay's standards, that's what they used. Adequate for the speeds they drove at night with night-adapted vision (not possible in brightly lit conditions which predominate today). I run original 21-3 headlight bulbs and drive over 40% of the time in darkness; if I had to watch for potholes &tc. I would drive no faster than about 20mph, but at normal nighttime speeds my headlights make me visible to other traffic more than light the road ahead for me. Streetlights and other car's headlights do that.
The 6v, 21-3 headlight bulb (with inverted-V filaments) was #1158. These later morphed into the tail light/brake light bulb for 6v cars that is still available today (with "clothesline" filament).
You can certainly run any dual-filament bulbs you like, but the notion that the headlights were designed for "hi-beam" and "low-beam" is false.