Ferg
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| posted on 3/1/05 at 06:53 PM |
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Sorry to be a bit late, but I voted for the monococque.....
But then I would I suppose.
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There are only two pieces of steel in the monococque, the upper seat belt mounts and they are about 2" square.
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imull
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| posted on 3/1/05 at 09:00 PM |
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The Clan Crusader was a GRP monocoque that only had 2 sections (upper/lower) as opposed to the commonly used 3 section manufacture.
Very easy to do and was far and away more torsionally rigid than any other sports car of its era.
The yield point is the point at which the material will go into plastic (permanent) deformation. Up until then it is considered elastic. After
reaching the yield point, a materials properties radically change and its ability to withstand an impact force decreases.
Cant explain it properly except to say that deformation increases up to fracture with a reduced force after the yield point is exceeded. So, you put a
load on and get to the yiepd point(graph gradient over 45degrees on Load vs Extension graph). Increase the load by a small amount and the extension
goes up by a large amount (graph grad very low)
Monocoques also tend to be more forgiving in a crash as they have a tendancy to fracture/ tear rather than buckle like a spaceframe does. On the
Circuit of Ireland years ago an Irish Clan pushed the B pillar of a sunbeam talbot to the tranny tunnel and had hardly any damage to teh corner that
hit it...
By contrast, a Lotus elise chassis is considered a writeoff if any part of the chassis is buckled!
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Hugh Paterson
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| posted on 3/1/05 at 10:49 PM |
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Ah the plot thickens, so what u intend for the composite, 1. Carbon and Carbon/kevlar, or 2. Carbon/kevlar and cross strand uni directional Cloth oh
wise one. Wanna hand?
Shug.
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Volvorsport
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| posted on 3/1/05 at 11:58 PM |
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hmm , what materials have you got spare from a big contractors job ?
Id like to know if you think a darrian is stronger than a clan - since ive seen clans after accidents and ive also seen plenty of darrians / repaired
em.
www.dbsmotorsport.co.uk
getting dirty under a bus
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imull
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| posted on 4/1/05 at 12:51 AM |
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couldnt honestly tell you. Though I have a Clan that was rolled/cartwheeled when flat out and suffice to say that it is still square and my spare
screen fits in the hole still... 300 hours of body repairs amd (mainly sanding) ~ never again will I rebuild the front corner on one from a Tesco
bag 
then went and bought another shell lol...
What would you say volvorsport? I would guess a modern T90 is tougher but probably only due to its size,integral steel cage and loadsa carbon/kevlar.
Were Clan about today, I reckon that they would be further ahead imho.
What sort of monocoque are you planning. Would be very interested in discussing it further if you want as its my field of interest anyway
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Rorty
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| posted on 4/1/05 at 02:35 AM |
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quote:
Originally posted by Volvorsport
as an example , the lanes Darrian had an off at about 90 mph , took most corners off the car , we stook it back in the mold and repaired it , a week
later he was running again , and that was extensive damage .
As you describe it, it's quite simple to repair damage, but what did that particular repair job cost in total?
I bet it wouldn't cost as much to repair similar damage to a Book Locost.
Your original post isn't clear about what sort of vehicle you're talking about. If you're thinking along the lines of a semi-coque
Locost, then my big question has got to be, why?
If you're talking monocoque generically, then I would probably vote "Yes, if I could afford it", but I doubt if I would own one. It
stands to reason, if something is well made, well proven and safe, then most people wouldn't have any qualms about driving one at least.
The crux is what sort of car are you talking about and how well would it be designed and built.
Until that would be established, I would have to vote "No, the concept is unproven."
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Volvorsport
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| posted on 4/1/05 at 01:39 PM |
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well , it will be 90% composite with a subframe at the front for the suspension , the rear will have a cradle for suspension .
My crux at the moment is designing where the subframe/ tub meet to be stiff . Im only going this route since a full monocoque will take space away
from engine bay - and thus reducing potential donors . Anyway , its being designed as we speak .
I know the darrian has been tested for stiffness , and i can say that its quite stiff - and that only had one layer of kevlar (450g) - to say that its
full of carbon kevlar is wrong since they have quite a thick laminate and a full FIA cage .
A TUB (e) version has subframes front and rear .
And after hearing about clans that used paper rope for a roll cage , and then the windscreen would pop out , tearing the roof back , i know which one
i prefer .
I dont think a book chassis would survive well enough to merit repair , if it had an off like the lanes did .
www.dbsmotorsport.co.uk
getting dirty under a bus
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Alan B
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| posted on 4/1/05 at 04:18 PM |
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quote:
Originally posted by Alan B
quote:
Originally posted by Volvorsport
...... . of course ally is safer than steel for the same strength since it has a higher yield strength .
Erm...?
What does that mean?
Sorry bad wording on my part...of course I know what yield strength is...I was just a little confused by your wording...
Did you mean that Ally of the same UTS as steel has greater yield strength?
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Volvorsport
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| posted on 4/1/05 at 04:32 PM |
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well , if im explaining it correctly , the point at which ally becomes plastic -ie above the elastic range (deformation) is a lot higher than steel .
i did say strength for strength basis so that would probably mean more thickness /weight . Thats why ally chassis arent as popular since they need to
be heavier to be as strong as the steel variant .
The upshot is tho that ally will protect you more in an accident .
www.dbsmotorsport.co.uk
getting dirty under a bus
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imull
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| posted on 4/1/05 at 07:54 PM |
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If using Ally, there are other aspects to cosider too. How do you go about creating your monocoque? The Yield point in the welded area of Alumium
drops to less than 50% meaning that you may as well use steel. Glueing/bolting/riveting are the only practical methods and even those have their
limitations ~ how many rivets would you ahve to use:
The paper cage was a rush job for teh Manx in 1972. They needed a cage and it met the rules of the day. It was tested by putting the car on its roof,
then putting a skip on its floor and filing with water to the required weight...
From what I have been told the screens really only pop out when people have not prepared/built their cars properly and this has caused problems.
I have 2 clan shells, both of which have been sucessful on rough surfaces (forrest stage and rallycross) back in the 70's/80's and in both
cases have yet to loose a screen!
Interesting to hear that they only have one layer of Carbon. I thought that Tim Duffee had mainly used it on them. Learn something every day.
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