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Re: Headlight Adjustment

To: <hjillson@argohouston.com>
Subject: Re: Headlight Adjustment
From: Barney Gaylord <barneymg@ntsource.com>
Date: Fri, 20 Nov 1998 12:08:38
At 08:44 AM 11/20/98 CST, Harlan Jillson wrote:
>    Dipped beam with 24" to center of the headlight and a 15 degree dip
angle should hit the ground approx. 25.5 feet in front of the car on level
ground ( if I figured it right).
>
>    I used :
>          Adj. side = 2'
>          Dip Angle = 15 deg., Leaving 75 deg.
>
>                  Adj. side
>          Hyp = ------------
>                   1 - Sin 75 deg.
>
>          then  hyp = 2/ (1-0.9238) = 26.274 '
>
>          then from the other end useing
>           adj = hyp * cos 15 deg.
>           adj = 26.274 * 0.9723 = 25.54'
>
>   So I ended up with the center of the beam hitting about 25.5 feet in
front of the car, which seems a little better than 7 feet.
>....

Uh, nope, wrong answer.  And it's easier than that, just height times
tangent of the big angle.
   2' x tan(75)    =  7.5'
   2' x tan(85.43) = 25.0'
So the small angle is 4.57 degrees for a drop of 2' in 25' distance.  And I
think that makes the lights a little too low for the high beams to work well.

Barnay Gaylord
1958 MGA with an attitude


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