Headlamps and starter motors.

[Keith Clements]

I was interested to read this article about the different XK headlamps.
This supplier or this have the required PF770 headlamps. Holden also supply adapters to convert to 7 inch units.

Whilst on a search I also found this hi torque starter for a Jav/Jup.

[PJGD]

The geared starter motor looks interesting; I bet it spins up the engine rather well.

I hope that they are aware that it has to run in the opposite direction from >95% of all other motors?

For quite a while back in the late '60's, I ran my Javelin with headlamps that I believe came from a Jaguar S-Type and they were distinct because the glass was concave instead of the normal convex. I understood the theory to be that being concave, there was higher pressure there in the center of the glass which kept the headlamps cleaner by continuously scrubbing the dirt away. I always thought that it actually worked although I could never prove it.

Philip

[Keith Clements]

Ricard Gane uses one on the race car. It is much lighter than the original.

The concave glass seems counter intuitive to me. If it was such a good idea then not many other cars adopted it. Bernoulli's Principle, states that pressure decreases when air moves faster. The pressure would be greater over a concave surface than a convex one as there would be an area of static air in the bowl formed. The net effect would be to make the car go slower and increase the Coefficient of Drag.
Whether such a scheme kept dirt from accumulating on the bowl is seriously in question as any particles would be heavier than air and carry more momentum to cut through the boundary layer. There would be no scouring action of water pushed along by the moving air stream .

Perhaps the SS was conceived prior to aerodynamics being understood or perhaps the design was just cosmetic. Those lamps now retail at £795 for reproductions!


I realise that is the SS not the S type of 1963 or the S type of 2000.

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