27 replies to this topic

[vale61]

HI everybody,

I'm trying to understand if the plexi windscreen used on old formula one cars (1960-1970) was clear or not.

Did it became yellowish during the sunlight exposure? Or was it really yellow?

I got a doubt seeing this picture : http://www.influx.co...c.KHnZIAbc.dpbs

 

Thanks.

Vale.

[arttidesco]

This selection of photo's show's that the 72 screens were by and large yellow.

[kayemod]

This selection of photo's show's that the 72 screens were by and large yellow.

 

A couple of guys in a building out the back at Specialised Mouldings used to make screens while we did the bodies for many F1 teams. They were all moulded clear and most were then tinted, as far as I can remember they were nearly all done in various shades of amber. I think McLaren preferred green on their CanAm cars, so that must have been an option.

Edited by kayemod, 21 October 2014 - 09:14.

[Joe Bosworth]

The polycarbonate (plexigtlass) of choice in the period that interests you was Lexan by GE.  Lexan was relatively expensive compared to competitors but in the greater scheme of things the cost difference made little differnce.

 

Lexan was the material of choice because it was highly formable and practically unaffected by things that would cause breakages and/or scratches.

 

Best of all it was the clearest product of the day.  Yellowness and haziness factors were lower than 1%.  It also did not yellow with age as cheaper products did.  I used Lexan on my BT15 rebuild in 1971.  I recently sold the car and the windscreen was as clear as the day installed.

 

Lexan was even more widely used in aircraft than in race cars due to freedom from breakiage and scratching.

 

If one digs back into old copies of Autocmobile Year from the period you can get a good idea as to who was using Lexan and who was using cheaper substitutes.  The beauty of Automobile Year is that they used the highest quality of photos and printing and paper quality so what we see today is at it was.  Other documents of the day give poor visuals by comparison due to ink and paper deterioration; all assuming that they were of accurate quality on the day they were printed.

 

Referring to several copies of Automobile Year I am surprised how many cars had hazy screens compared to competitors in the same frame of photos.  I can't tell whether the haze is poor quality product or tinting.  I don't see any that are particulalrly yellow.

 

Regards

[Doug Nye]

Kayemod is correct - the screen transparencies did have an amber or yellow tint, beginning with the 1967 green-and-yellow Lotus 49s. The car with which I was closely involved, 'R3' still had its original yellow-tinted screen when it came back from South Africa, and I believe there was a spare with it, which we used in the restoration, because the original (which I still have) had an aluminium-framed insert riveted to it. This ex-Lotus yellowed screen was then smashed in the unfortunate NMM crash which the car suffered. It was then rebuilt by Hall & Hall, but they could find no modern replacement for the original amber/yellow material and so the car survives today with a clear screen. Which is wrong. Note - the screens were NOT yellowed with age as was assumed by both the NMM and the re-restorers. They were yellow from new.

DCN

[2F-001]

Plexiglas (strictly speaking a trade name) is actually acrylic (like Perspex), rather than a polycarbonate like Lexan.

[kayemod]

Note - the screens were NOT yellowed with age as was assumed by both the NMM and the re-restorers. They were yellow from new.

DCN

 

True.

[vale61]

Many thanks to all!!!!!!!!

 

Does anybody know the reason of using a colored screen? Could it be to avoid unwanted reflections?

 

Vale.

[Rudernst]

just to clear this up

 

Plexiglass (Acrylics) are tough but shatter to dangerous shards under shock load

that takes some doing, yes but at some point it happens

 

Polycarbonate is more flexible, does break but does not shatter into dangerous bits

 

Plexiglass is perfect for coffee tables

it is dangerous for certain other uses

 

helmet visors and screens are made from PC for this reason

 

just to save some homebuilder from trouble

 

R.E.

[kayemod]

A little more on McLaren screens. The M5 was clear, the M7 green, as were the M6 and earlier M8s. Later McLaren F1 & CanAms sometimes had clear screens, and sometimes green. The yellow/amber colour didn't really go well with McLaren orange, but I recall working on Peter Revson's M16 that had an amber screen, so maybe some of this was down to driver preference, but orange/green always looked best to my eyes. The pic below is a Michael Turner painting of three M8Bs dominating at Michigan International Speedway in 1969, the scene of a Bruce/Denny/Dan Gurney 1-2-3. Orange and green just looks so right doesn't it?

 

 

This pic appears in Phil Kerr's excellent book To Finish First, in my opinion one of the very best books on motor racing up to the mid-70s or so ever written, a true down to earth insider story, everyone with an interest in how racing used to be before money dominated everything and you-know-who took over should read it.

Edited by kayemod, 21 October 2014 - 15:45.

[D-Type]

I still don't understand people tinted the screens.

[kayemod]

I still don't understand people tinted the screens.

 

I suspect mainly because they thought it looked good, though there was probably some thought of anti-glare protection as well. At McLaren Denny was quite safety conscious, in the days of old-fashioned fibreglass, we used to stiffen flat panels with a grid pattern of carbon fibre tows laid on the inside of panels, this was before the stuff was economically viable in sheet form. I think it was Denny who got SM to stop this after he or some other driver got stabbed through the hand in a minor crunch after the tows separated to form a spear. The saga of tinted screens might also be a Denny driver safety influenced move too, as Rudernst said, Plexiglass can shatter, while polycarbonates like Lexan don't. I don't know as I've never been involved in screen manufacture, but maybe it isn't easy to tint Lexan, hence the later predominance of clear screens.

[PCC]

I suspect mainly because they thought it looked good, though there was probably some thought of anti-glare protection as well.

Does simply tinting a screen reduce its glare? I wouldn't have thought so. I do recall some drivers using amber visors on cloudy days, the theory being that an amber 'filter' increased contrast in overcast conditions (there's one for The Photographers' Thread!). But how much did they look through, rather than over, the screens (as you can tell, I've never sat in one...)?

[Bloggsworth]

Most British F1 cars had screens of toughened Perspex (White Ellerton in Barnet were experts in the field) - NEVER polycarbonate, as it crazes when it comes into long-term contact with hydrocarbons. IIRC, they tried to make motorcyclists crash helmets from polycarbonate, but the stickers, which used hydrocarbon based adhesives, caused the helmets to shatter when they shouldn't have.

Edited by Bloggsworth, 21 October 2014 - 17:24.

[Doug Nye]

Since drivers commonly looked at the world over these screens rather than through them I suspect tinted screens were chosen more for the way they looked than with any great concern for the view once a driver looked through them. In the Lotus 49 the amber/yellow tint certainly simply matched the green-and-yellow Team Lotus livery. The screens survived the change into GLTL fag packet livery of red, white and gold. In the later JPS series their colouring picked up the gold - or faux-gold - pin striping and lettering in the brand livery.

DCN

Edited by Doug Nye, 21 October 2014 - 17:30.

[BRG]

I do recall some drivers using amber visors on cloudy days, the theory being that an amber 'filter' increased contrast in overcast conditions (there's one for The Photographers' Thread!). 

It certainly does, as any skier will confirm.  But as DCN points out, you didn't look through these screens.

 

Anyone remember those little fly deflectors that they had on the front of cars many years ago?  They were usually yellow perspex.  Wonder why?

[PCC]

But as DCN points out, you didn't look through these screens.

That's what I figured, thank you both.

 

Of course, that raises the question: if the driver isn't loking through it, why make it out of lexan? Why not just make it part of the bodywork, and paint it whatever colour you like? Thinking of the early '70s, I recall that the lexan windscreen on the Lotus 72 got progressively narrower, and it disappeared on the Tyrrells altogether by 1972.

 

Sorry if this is all a bit pedantic...

[arttidesco]

SOT I used to have a pair of yellow tinted shades for mountain biking, great when going through woods with overhanging trees and lots of shadows but like having head phones turned up to 50, on a scale of 1 to 10, in normal day light, i.e. rather than reduce glare they amplified it in normal day light to a quite painful degree.

 

BOT in the light of that experience I can only imagine wearing a yellow visor in the kind of conditions Denny Hulme frequently did would have inflicted a lot of pain on my eyes, which makes me wonder if he had some sort of contrast sensitivity impairment ?

[kayemod]

Of course, that raises the question: if the driver isn't loking through it, why make it out of lexan? Why not just make it part of the bodywork, and paint it whatever colour you like? Thinking of the early '70s, I recall that the lexan windscreen on the Lotus 72 got progressively narrower, and it disappeared on the Tyrrells altogether by 1972.

 

Sorry if this is all a bit pedantic...

 

The fact that all cars had clear screens makes me wonder if the F1 rules required them, though I've never seen anything of the kind in print. It puzzles me somewhat that current F1 monstrosities all seem to have tiny clear "screens" that are barely an inch high, and only right in front of the driver. I've known drivers say that spots on the screen were their first indication of rain, but surely there's more to it than that? I think that even those "screen-less" Tyrrells had tiny screens, I assumed at the time it was to satisfy some regulation or other.

 

Wasn't that Denny Hulme amber visor just a short-lived experiment, which presumably didn't improve things, there was nothing wrong with his eyesight as far as I know.Back in the days when I spent a lot of time flying model planes, some others wore amber tinted visors, allegedly they improved vision when trying to track a small fast moving object against a dull sky, though they didn't work for me. Anyone remember that entire upper body section made from Plexiglass or some such material, that Graham McRae had on one of his F500 cars?

Edited by kayemod, 21 October 2014 - 22:13.

[PCC]

Anyone remember that entire upper body section made from Plexiglass or some such material, that Graham McRae had on one of his F500 cars?

Wow, I did not remember that, but a quick Google reveals a Marc Sproule photo of it!

[2F-001]

There was (and still is?) the Lotus 'Exposé': essentially a 340R with transparent bodywork (I have pictures somewhere) - supposedly inspired by an unpainted radio controlled model; last seen (by me) at a Lotus-themed event at Prescott.

That - and Bloggsworth's comments above - lead me to another (somewhat O/T) though. After the transparent vacuum-moulded bodies for slot cars and r/c cars began to made from polycarbonate (rather than some kind of styrene?) it was found if you painted them with the typical modelling enamels some property of the polycarbonate which made it tough and resilient would be leeched out by the paint and at some point later when you'd cartwheeled your pride and joy off the banking at a commercial raceway at 40mph or your r/c car into a concrete post, the body could, indeed, shatter.

The answer seemed to be painting the car with emulsion paint; you'd have to roughen the surface slightly first, but since the norm was to paint them on the inside you could still get a decent finish.

I remember Denny Hulme using a yellow visor, but I'd assumed he only used it in dull conditions.

Edited by 2F-001, 22 October 2014 - 05:57.

[2F-001]

Nice pic of the McRae… (GM3??)
I think it lost some of that elegance (but gained in performance) in later developments, didn't it?

[lanciaman]

Windscreens were tinted for the same reason my goggles came with tinted spare lenses: to reduce glare.  I never found the amber or smoked lenses to be particularly effective and did what most other drivers did by using electricians tape to narrow the eye slit on the clear lens.  (I have a personal photo that my friend Yogi Behr took of Jimmy moments before he went on track at Hockenheim, and the windscreen of his Lotus F2 car is decidedly yellow.)

[BRG]

In the current World Rally Championship, I notice that both Latvala and Neuville seem to wear amber glasses when in action.

[arttidesco]

 

 

Wasn't that Denny Hulme amber visor just a short-lived experiment, which presumably didn't improve things, there was nothing wrong with his eyesight as far as I know.

 

Denny used yellow tints pretty consistently, though by no means exclusively from at least 1967 to 1974

[ray b]

the plastic is normal clear but is factory made in many colors

 

when I made hatches for my boat I went to a plastic's shop

they had every color in many shades in 4'x8' sheets

when cut the color was all thru the piece

 

I donot think they used films or dye/tints back then

just bought the sheets in whatever color or shade

[antonvrs]

Pegaso built an entirely clear plastic(Plexi?) bodied show car in the early '50s.

[arttidesco]

Pegaso built an entirely clear plastic(Plexi?) bodied show car in the early '50s.

 

Pontiac did something similar... in 1939