Lights on prewar British tanks

[Richard Farrant]

Does anyone know the reason why some prewar British tanks, had two rear lights, one red and the other blue? They were controlled by one switch so only one was lit at one time. It may have been some form of signal or warning, perhaps. It is mentioned in the 1939 edition of Manual of Driving and Maintenance for Mechanical vehicles (Tracked), but not why.

Richard

[Tony Smith]

Australian Carriers also have this Red/Blue taillight arrangement. The Carriers also had Blue lenses in the Head lamps, so one could speculate (from Railway practice) that the colour of the tail lamps was changed when changing direction of travel, that is when travelling forward at night blue lights would be shown at the front and red at the rear, but when reversing, the rear lamps would be blue to indicate the vehicle is coming towards you, possibly also showing more light on the ground to assist in the movement.

[Richard Farrant]

Originally posted by Tony Smith
[B but when reversing, the rear lamps would be blue to indicate the vehicle is coming towards you [/B]

Tony,

That sounds feasable, but the headlights, or in this case only side lights on the front, do not have coloured lens mentioned in the handbooks. It may well be the procedure was to switch the rears to blue if backing up. I will go along with that until another theory comes along.
Thanks.

Richard

[Dave Page]

I always wondered about the two colours, now it may make sense. However, it would be nice to know for sure.
On a similar subject, regarding blackout head and side lamps, I have noticed new old stock ones finished in matt black, and not just the masks but the entire body (inside and out) as well. Was this just the primer they were supplied in, as I know green will cover black more readily, or was this intended as a non-reflective finish?
Cheers,
Dave

[Richard Farrant]

Originally posted by Dave Page
I always wondered about the two colours, now it may make sense. However, it would be nice to know for sure.
On a similar subject, regarding blackout head and side lamps, I have noticed new old stock ones finished in matt black, and not just the masks but the entire body (inside and out) as well. Was this just the primer they were supplied in,

Dave,

I am sure this the matt black is only intended as a primer as the lamps often have stencilled inspection stamps on the outside of them in yellow paint. Those made post war are usually in Deep Bronze Green.

Richard

[Dave Page]

Hi Richard,
yes, I have noticed the inspection stamps on the lamp bodies as well. Would vehicles have left the factory or have had replacements fitted in field and still been finished in black, until the vehicle was repainted later?
The question on the masks still remains. I can see the benefit of having the masks, or doors, finished in black, were they left unpainted during the war? I have looked at lots of images but it is hard to tell as flat paint tends to almost absorb any dust about, making it all blend in together (which is the whole point of camo).
Thanks,
Dave

[Richard Farrant]

Originally posted by Dave Page
Would vehicles have left the factory or have had replacements fitted in field and still been finished in black, until the vehicle was repainted later?

Dave,

When parts were produced during the War, especially standard items such as lamps which could have been fitted to anything, the vehicle colour scheme would have been unknown. Early on it could have been Light Stone, Brown, several shades of Green. Thus, if a lamp was fitted and there was no opportunity to paint it at the time, then matt black is the most logical primer, better than red oxide or grey primer which would compromise the camouflage scheme of the vehicle.

Richard

[Dave Page]

Hi Richard,
I understand how simple it would have been to paint in matt black primer during manufacture, then to touch-up later when fitted. However, that does not explain the red primer underneath the matt black. I am not saying - all - lights were finished in this way but I have a couple of examples, which are Butler side lamps that have the smaller lens aperture with the blackout "shield" behind the glass. This "shield" has pinholes, so are really blackout side lamps. I must dig out the headlamps and check them as well.
Just another mystery to solve - it what makes this hobby interesting.
Cheers,
Dave

[Neil Ashley]

Dave

I would agree with Richard that the black is a primer. I have never observed an additional primer underneath the black.

Regarding the disc with pin holes in between the reflector and glass, this was standard on war-time production British and I believe Canadian pattern side lights. Only the slightest glow was meant to show.

On one model, either lucas or Butller, the exterior rim also wraps futher round the rim to give better shielding.

Regarding head lights, it was common early in the war to horizontaly paint the top half of the reflector to reduce light spill.

Originally posted by Richard Farrant
Does anyone know the reason why some prewar British tanks, had two rear lights, one red and the other blue? They were controlled by one switch so only one was lit at one time. It may have been some form of signal or warning, perhaps. It is mentioned in the 1939 edition of Manual of Driving and Maintenance for Mechanical vehicles (Tracked), but not why.

It would be a huge clue if there was a similarly operated green one at the front perhaps, I'm guessing here and do not recall the correct order but don't army convoys carry a green flag at the head and a blue one on the last vehicle? Or is it the other way round?

R.

[Richard Farrant]

Originally posted by FV623
It would be a huge clue if there was a similarly operated green one at the front perhaps, I'm guessing here and do not recall the correct order but don't army convoys carry a green flag at the head and a blue one on the last vehicle? Or is it the other way round?

Other way around, I always remember it as green at the rear for "all clear". Anyhow, as it explains in the D&M Manual, red or blue may be fitted to rear but no mention of coloured lens to front lights. I will go along with Tony's theory about reversing with blue light on, until more proof is found.

Richard

[Tony Smith]

From the Aust "Carrier, MG, Instruction book":

Originally posted by Richard Farrant
Does anyone know the reason why some prewar British tanks, had two rear lights, one red and the other blue?

Done a bit of digging. . . . . . . . . . . .Well, I asked my chum David F in Bovvy.

It is the early version of a convoy light, tanks not having an external, rear mounted and underslung diff casing to conveniently paint white; low vis and not visible from above.

R.

[Richard Farrant]

Originally posted by FV623
It is the early version of a convoy light, tanks not having an external, rear mounted and underslung diff casing to conveniently paint white; low vis and not visible from above.

Hmmm. not entirely convinced with that as both lights are side by side over the rear number plate and blue would be just as visible as red. But maybe that was why they turned to a white light shining on white down below.

Richard

Originally posted by Richard Farrant
Hmmm. not entirely convinced with that as both lights are side by side over the rear number plate and blue would be just as visible as red. But maybe that was why they turned to a white light shining on white down below.

Richard

Maybe, however, the eye is most sensitive in the low end of the spectrum which is red (700nm) and at its least at the high freq end which is blue (390nm). A 3W bulb behind a dark blue lens would be quite feeble and probably inconspicuous at any distance.

R.