does any one happen to have...

[russ]

a 3 model, or 2d drawing with accurate dimensions for the lancia stratos windscreen? or at least just accurate dimensions??
i would love to just go out and buy one from omicron, but im no where near needing it and i just know it will end up in pieces!
im designing a kit car using the screen, but its only paper (well auto cad at least.) so far, and i dont even have my workshop yet, (its attatched to the house ive just bought and im waiting for my useless solicitor to do his job) so coud do with some dimensions to bung into auto cad to be able to continue with the design.



Thank you,



Russ.

[mogul_x]

Russ,

I've got a Hawk windscreen that I haven't yet installed in my car. I might be able to take some dimensions off of it if you aren't able to find them elsewhere.

I can't guarantee the accuracy of the dimensions, though - that screen is a pretty complex shape. Measurements taken by hand will be very approximate.

I might be able to use the FARO arm at work to make a 3-d surface map, but I'll have to look into it. I'd need to get the boss's permission, or at least conscript one of the technicians into operating it for me. I also need to look into whether we have any rubber tips for the arm - I don't want to risk breaking or scratching a very expensive piece of glass!

[russ]

that would be very helpfull scott, i really just need the overall width at top and bottom and the tangent offset at top and bottom + the angle and length of the front slope (probably best relative to the screen being stood upright resting on the bottom edge) everything else will probably fall together in cad, plus i think the hawk one is slightly different from the omicron one any way. but anything within an inch is fine (obviously the more accurate the better tho :) ) just so that i can rough out the frame work and get a better idea of how to locate the screen for aesthetics etc.
ive tried scaling it off of photos using dimensions from the full car with poor results, probably due to perspective and dimesions not being related to the particular photos i was using :rolleyes:



Thaks for your help,



Russ.

[chris.richard]

What part of the country are you in Russ? There are replicas dotted about, I'm sure someone near you would let you run a ruler over theirs.

[russ]

im in barnsley, south yorkshire. have never seen a stratos round here. maybe difficult getting the dims while the screen is on the car tho?



Cheers,



Russ.

[roger001]

I'm about an hour away from you in Beverley , north of Hull, if its of use, tho the windscreen is in the car.

[russ]

thanks for the offer roger, ill see if scott can sort me out first. would love to see a stratos up close tho! never seen one in person. i enquired at hawk to get at kit a while ago and nearly had a heart attack when i saw the price :eek: , bit too expensive for me :D


Cheers,


Russ.

[AndyH]

Hi Russ,

I live in Holmfirth, which is a stones throw from Barnsley.

Window is not in the car yet (in fact not much is in the car yet), so if you want to come and take some dimensions, give me a call... 01484-686417.

Re the window dimensions, I read in one of my Stratos books that the windscreen was designed around a constant radius curvature to help eliminate distortion as you look from middle to side etc... Once you've got the radius, the windscreen is then just a section from a cylinder.

Andrew

[Andrew Way]

Isn't the monarchy already in enough trouble? :D

Sorry, couldn't resist it .......

[Bernard]

Russ

I am also not too far away...i have a spare screen out of the car which you can measure

Radcliffe on Trent, Notts..........

Bernard

[mogul_x]

Russ,

It sounds like there are a couple of screens you can measure in person not too far away from you. If you'd still like me to look into making a 3-d map, let me know. I'll try to find out what would be involved in doing so on my end.

cheers,

[russ]

cheers scott, i think a 3d map would be a bit ott, i just need basic dimensions so i can rough out the frame work. would it possible for one you guys to take the measurements for me? ive just had a crap load of contracts dumped on me at work and doubt ill be able to get away, (plus im an idle git :D :D )
any thing within half an inch will be fine, (metric would be preffered tho :) ) just so ive got an idea.



Thanks,



Russ.

[russ]

Thought i would post a piccie, incase anyone was interested. the screen surround is a guess obviously.

[mogul_x]

Russ,

Just found out that the FARO arm will be unavailable for a couple of months. The "key" that fits between the cable on the arm and the computer that runs the software is currently being used on an arm at another plant. Not sure when we'll be getting it back.

If nobody else volunteers, I'll take some dimensions for you the old fashioned way, when I get the chance.

regards,

[russ]

that would be great, cheers scott.







Russ.

[rutthenut]

Originally posted by AndyH
Re the window dimensions, I read in one of my Stratos books that the windscreen was designed around a constant radius curvature to help eliminate distortion as you look from middle to side etc... Once you've got the radius, the windscreen is then just a section from a cylinder.

I thought that it was a section from a cone, not a cylinder, but for the same reasons - using constant radius curvature throughout. It could just have been my mis-interpretation of what I read though, or either of the books might be slightly incorrect???

If that is the case, you would need to know the radius of the upper and lower edges, plus the vertical distance between them, and it should work out easily enough from there. Also need the width or angular range for the upper and lower arcs, I guess.

But I don't have the figures available, I'm afraid.

[AndyH]

Well spotted John, It would be difficult for it to be from a cylinder the shape it is....
Andrew

[Andrew Way]

I don't see why it can't be cut from a cylinder............ this model is drawn using a cylinder and looks fairly close.

[edit].... but its a bullet proof version with 1" thick glass!!!

[AndyH]

Ref window dimensions.. I've measured the following:-

765mm straight across the narrow edge of the screen (across the top as the screen sits in the car.

1165mm across wide edge of screen. (across the bottom as it sits in the car)

Side edges measure 420mm long

The length of the glass (middle of bottom curvature to middle of top curvature) is 725.

With the glass sitting on the long curvature (as in the car) it measures 230mm from floor to middle of top curvature.

If you sit the glass on the edges it measure:-

100mm from floor to middle of short curvature
300mm from floor to middle of long curvature.

Ref the constant radius bit.... not sure about all that looking at the glass. It's not from a cylinder for sure... could be from a cone, but a helluva funny section. The long curvature looks to be a tighter radius than the short curvature (which is different to what I though).

There's one thing for sure... I don't want to break it, so next time it comes out it'll be going in the car !!

Andrew

[russ]

cheers for that andy, tis miles different than i guessed in width. trouble is, youve taken dimensions with the screen in 2 different positions, and their is nothing to reference them to each other. all i need is the distance from the middle of the front of the bottom radius to a line between the corners of the bottom radius at the widest point of the screen (the tangent) should be able to this with the screen in the car if anyoen could oblige.




Thanks again,



Russ

[Andrew Way]

I still think its cut from a cylinder....

Because the A posts aren't parallel its easy to see it as a cone.

[rutthenut]

Originally posted by Andrew Way
I still think its cut from a cylinder...

I agree that this may well be the case - neat graphics too - but I thought I had read something about a cone some time ago.

Whether or not that is just the visual interpretation, I have no idea. I suppose it would be slightly easier to make something up based on a plain cylinder, albeit with an 'angled section' from it, and the effect would be much the same.

Comments about the different radius at top and bottom of screen would be a clue as well. If the bottom curve is a tighter radius, that would be because it is closer to the actual radius of the cylinder, whereas the top curve is a larger radius due to the shallow angle across the cylinder.

If it were a simple section from a cone, the radius would be tighter at the top.

I guess that the curve also is not a proper circular arc section, if from a cylinder, but an ellipse of some sort. A cone would have a circular curve, but an angled cut through a cylinder would be some other shape, wouldn't it?

Anyway, it seems that there are plenty of figures measured so far - enough to answer the original question yet?

[AndyH]

Great graphics.

I had a look across the face of the windscreen last night and it does appear to have a flatter section in the middle of the screen and then curved at the outside.. (Like a "normal" windscreen)

This could be just how it ends up post manufacture rather than the theory around how it was designed I guess.

For the purposes of the design excercise (where all this started), I guess a section from a cylinder is going to be the easiest to use and be close enough to reality ??

Cheers

Andrew

[AndyH]

all i need is the distance from the middle of the front of the bottom radius to a line between the corners of the bottom radius at the widest point of the screen (the tangent)


This is 540mm

Andrew

[russ]

sorted, cheers m8!!

[chris.richard]

Nigel Trow says (p22) "..curved in a constant radius to avoid distortion."
That would have to be a bit of a sphere for 3d accuracy, or a cylinder for 2d.

Sorry, my body's off work with this Fujan flu, and my mind is getting bored...anoraks are nice and cosy though! :cool:

[David May]

As far as I can tell (using rulers and string) it is indeed a section of a cylinder, with a constant radius of almost exactly 100cms. I can only get enough length in the car by measuring from where the tunnel meets the rear bulkhead, but that makes a pretty good perpendicular towards the top of the screen. Shows how tiny the whole car is when you cannot get further away than 1 metre from the screen.

Dave May

[BAS]

I can create a 3D map of the screen surround / body tub using a laser theodolite if that would help. Are you using AutoCAD or would a DXF file be better. We should then know for sure if it's a cone or a cylinder.

[David May]

I'm not sure that my CAE's 'Velas' screen is a true replica , but if I run 2 straight edges parallel down the outer edges, they lie exactly flat on the glass (at any other angle they are on curved surfaces.) It can't be conical.

Dave May

[russ]

iam using autocad 2002. if you look straight down the screen as i have drawn it, it definately is not a section from a cylinder, but my interpretation of andy's dimensions could be dodgy as could the way ive drawn it.




Russ.

[David May]

You're only going to see a true cylindrical section if you view it from iinfinitely far away. Have you tried laying the image over that of a true cylinder?

Dave

[chris.richard]

It doesn't need to look like a cylinder to be cut from one - you could cut a star shaped windscreen and it could be part of the surface geometry of a cylinder.

[russ]

3d view in cad 2002 is isometric not perspective so it doesnt matter how far you view it from, looking down the front edge of the screen there are 2 distinctly different radi, but like i said my drwing could be out a bit.

[vojx]

Originally posted by chris.richard
Nigel Trow says (p22) "..curved in a constant radius to avoid distortion."
That would have to be a bit of a sphere for 3d accuracy, or a cylinder for 2d.


Having read my Nigel Trow bible recently (only took me 13 years): it also states, somewhere near the end, that the windscreen is a section of a cone. :D I could give chapter and verse if necessary.

Added: Chapter 9, verse 3 (page 144)

[Arthur]

Guys,

I recall some 2 years ago talking to Hennessey Racing at Birmingham show - he was quite eloquent re. the "section of a cylinder" argument, having had his decal manufacturer run a few (hundred) up for advertising based on this well-known nugget of info.
Result - he could hardly get a fit with scissors and stanley knife.
Said decal man reckoned "no way was it ever near a cylinder" - the shape was all wrong in all sorts of ways.

And I got a Finnish Strat original screen for mine. I don't know what shape the screen was, but it sure as hell wasn't the same shape as the car.

What you do is, working very quickly, so at least one dry run first to convince yourself it'll all work is :-
Get a minimum of 2 x 200 Kilo ratchet straps. Mount the wheels. They have to be 4 or 5-spoke.
Get a load of offcut timber.

Clag the screen in UV-resistant goop.
Offer the windscreen to the hole. Put more and more clag where it doesn't fit - like everywhere.
Stretch one ratchet strap from the rear wheel spoke, over the screen, to the diagonal opposite front wheel spoke, and ratchet til it just holds in place.
Do the same crosswise with the other strap. Have a third ready, rear wheel to rear wheel, just in case.
Now take loads of offcuts, and jam them under the straps where they don't fit too well, til you have even pressure around the screen, which is hopefully in the hole, as opposed to pushed into the cab, or slid down the bonnet.
Be prepared to believe that you can bend that screen into a 3/4 inch gap, and the goop will hold it there.
Now clean off all the goop you didn't need, and wonder again how anyone can sell a product so impossible to clean off.

In nautical parlance, substitute the word "dunnage" for "wood offcuts", and we have just described a stowage technique known as "Tomming Down".

Don't blame me if you break one. Just go easy til you're sure in the dry run.

The alternative is to totally re-laminate the screen aperture, and probably the front half of the tub.
This was a Corse, by the way - no idea about anything else.

Mine is still there after nearly 5 years now, and I still have trouble believing it.

Happy building, Lads.
Arthur.

[Sando]

Wow Arthur Best of luck with the screen. Sounds like a stonechip away from a large crack to me. I've heard of stressed engines and gearboxes but not a widscreen.:D

I suppose that answers the question about the corse and its relations and Genuine screens then.
A genuine screen fits the Hawk, I was lucky enough to come across one and I got a local fitter to bond it in for £40. It only took a length of sponge tape around the edge of the body and 10 mins later it was in with the trim on. Glad it was straight forward, I don't think I could have coped with doing what you had to do.

cheers
Rob:cool:

[Arthur]

Rob,

Its not so bad when you take the hyperbole out of the equation.

That screen is HUGE.
Its toughened glass, and its laminated.

The toughening - well, its so stressed anyway in the surface layer that any extra bend you put in it won't make any odds. You could lie it flat and free, and a chip would shatter the lot regardless.
The laminating layer is really a flexible polymer layer, so it will accommodate some shift in the glass planes. Bear in mind the Strat body is effectively unstressed, but these screens are normally fitted direct onto stressed monocoque structure, and still survive.

To give you an idea, Pilkington's Glass place has a demo where a 6-foot x 1/4 inch x 12 inch piece of toughened glass is twisted over its entire length by 180 degrees, (really, stupefying to watch) again and again.
Far as I know, that dem has been there, doing that, every 10 minutes, for nearly 30 years.

I was more worried that the glue would hold it, and that the fibreglass laminations would remain intact under the stress. I've already had the horrible impact at speed - no damage as far as I can find. Just like a real car, in fact.

Wateright, of course - now that's a different matter.

Never say die, there's always a way, blah blah etc.

Arthur.

[Andrew Way]

Time to start a debate on whether glass is a liquid or a solid at room temperature?