Volvorsport
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| posted on 10/12/04 at 06:46 PM |
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POll : monocoque or steel
alright , since i completely missed the poll button , ill delete the other thread and you can re vote :
Now for ever who said it wont be too cheap : dont count yer chickens before they hatch . ill leave the price out - i want people to vote on wether
they would buy one and have no misconceptions about driving a GRP/kevlar/carbon tub about .
www.dbsmotorsport.co.uk
getting dirty under a bus
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Staple balls
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| posted on 10/12/04 at 07:00 PM |
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Bugger, just finished typing a reply.
I think a monocoque setup could work very well indeed. However i would have concerns about the resistance to damage, it's a few years since i
looked at this stuff in any detail (and then it was in push-bike frames)
My worry would be that if you did get a nasty gouge in the tub that it could affect the overall structure massively, also it would be very difficult
to add/remove parts or to make customisations.
The beauty of a steel spaceframe is that any muppet can pick up a welder and add bits, change stuff around and even make the whole lot themselves, you
can't do that with CF.
I think it's almost like comparing C4 to gunpowder.
C4, you can do what the hell you like with, even burn it and cook over it safely.
Gunpowder is safe in the right conditions, but can get very dangerous very quickly.
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Volvorsport
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| posted on 10/12/04 at 07:15 PM |
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if it gets damaged , send it back to the factory for repair !!
it wont be completely carbon - a mixture so that its cost /strength all lay within acceptable parameters for the home builder . Although you wouldnt
be able to change the physical dimensions so much, i believe its easier to adapt than you might think .
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 . like i said in the other thread
http://www.locostbuilders.co.uk/viewthread.php?tid=19993 there will some steel in the shape of a roll cage and front an rear chassis sections that
will be the same as book dimensions or +4
www.dbsmotorsport.co.uk
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Dale
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| posted on 10/12/04 at 07:48 PM |
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I would not be too concerned as long as the design has some modular design to it. It would be nice to have a bolt together chassis that can have the
major components replaced instead of having the entire tub ect replaced.
Dale
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undecided
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| posted on 10/12/04 at 11:56 PM |
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Extreme is a stainless steel tub and been around for a good few years now so nowt new there.
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Volvorsport
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| posted on 11/12/04 at 12:29 AM |
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well , the point is , its a composite monocoque , im well aware its been done before , and shall be done again .
www.dbsmotorsport.co.uk
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gazza285
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| posted on 11/12/04 at 12:48 AM |
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Who voted for Steel performs better? Dark ages of motoring history.
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Aloupol
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| posted on 11/12/04 at 01:29 AM |
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At least me...
As "performs beter" I don't mean steel is lighter or stronger  but I think in the case of a Locost or related it gives some
advantages: easy to built, repair or mod, cheap, afordable calculation if you want to optimize etc.
How much will carbon be lighter and stiffer?
For my car I will probably use a mid way solution: a steel frame with aly sandwich paneling around the cockpit cell.
Square tubes of 25 with inside and outside 1.6 (or even 1.2) paneling, with a 25 thick honneycomb core between both panel.
The honneycomb weights nothing and it can make even a thin sheet become structural.
As anyone used this solution?
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andylancaster3000
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| posted on 12/12/04 at 03:06 PM |
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Nobody has mentioned an aly monocoque. There aren't many about and I don't think Robin Hoods' idea has really proved that its a good
concept very well!
Mr. Chapmans monocoque F1 cars were constructed in aluminium and these proved rather affective.
In my archive are a few pictures of an aly chassis. Other than a small front and rear subframe and suspension pick-up points made from steel it is all
constructed with sections of folded sheet aly. The sections are then riveted together with Araldite on all joints. In my opinion this method is a lot
easier to get true than a spaceframe. Construction is also very quick to build, unlike a composite chassis and above all, VERY light!
I admit that for the purposes of a locost if in regular use on the road could, be susceptible to problems with fatigue. There aren't many front
engined monocoques around either. They are generally mid engined cars with the engine as a stressed member or engine/box/rear suspension on a seperate
subframe. But with some thinking a front engine design could be achieved.
Andy
[Edited on 12/12/04 by andylancaster3000]
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Volvorsport
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| posted on 12/12/04 at 05:21 PM |
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well , its true that it may be easier , but a composite chassis can be just as easy to build - i shall attempt to prove that . I dont think an all
ally monocoque is any lighter though - to a comparable strength , my intention is still to have a full roll cage anyway .
www.dbsmotorsport.co.uk
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andylancaster3000
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| posted on 12/12/04 at 05:27 PM |
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Sorry, i didn't mean for it to say that it was very much lighter then a composite chassis but for its weight, I think it would be considerably
stiffer then a spaceframe 
Andy.
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Volvorsport
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| posted on 12/12/04 at 05:47 PM |
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id agree with that , although im a little apprehensive about driving a pop riveted bit of ally about , that really does suit racing cars more -
imagine all the deburring youd have to do aswell . of course ally is safer than steel for the same strength since it has a higher yield strength .
Once a mold is made , you build it without a single seam or join , which also contributes to strength .
www.dbsmotorsport.co.uk
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andylancaster3000
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| posted on 12/12/04 at 07:17 PM |
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That composite chassis idea sounds interesting. Would you bond in steel lugs for the major components then or would you try something fancy with the
mould?
I would agree with your concerns about driving the riveted chassis on the road. However the car in my archieve raced many seasons without a hint of
rivet failure, but that was with high quality rivets (about 2000 of um!)
Andy
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Volvorsport
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| posted on 12/12/04 at 08:38 PM |
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yeah , i shall be bonding in attatchment threads/lugs where necessary , some will be dowelled to allow removal/replacement etc .
At the momnet still designing/sketching wether it would be possible to have the whole chassis as composite without the need for the front suspension
subframe .
www.dbsmotorsport.co.uk
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krlthms
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| posted on 12/12/04 at 10:28 PM |
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quote:
Originally posted by andylancaster3000
There aren't many front engined monocoques around either. They are generally mid engined cars with the engine as a stressed member or
engine/box/rear suspension on a seperate subframe. But with some thinking a front engine design could be achieved.
Andy
[Edited on 12/12/04 by andylancaster3000]
McLaren Mercedes SLR?
KT
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Volvorsport
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| posted on 12/12/04 at 11:09 PM |
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What about Lister Storm ?- could you consider a marcos for mocoque , not truely 'composite' , but a monocoque chassis of sorts.Maybe i
shouldnt define it as monocoque - merely composite chassis ?
www.dbsmotorsport.co.uk
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andylancaster3000
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| posted on 13/12/04 at 11:17 PM |
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What is the exact definition of monocoque? From my understanding nearly every road car chassis falls under the definition of monocoque!
One of the best, most developed, composite chassis I have come across is the GTM chassis. I was quite suprised with how little metal is the the
chassis but they assured us of its strength with 20 years of development in it!
Andy
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Alan B
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| posted on 14/12/04 at 04:02 AM |
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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?
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Staple balls
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| posted on 14/12/04 at 05:04 AM |
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mon·o·coque n.
A metal structure, such as an aircraft, in which the skin absorbs all or most of the stresses to which the body is subjected.
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Volvorsport
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| posted on 14/12/04 at 01:04 PM |
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higher yield strength - if ive got this correct is when the material has gone beyond its plastic range (deformation) , ally take a lot more energy to
"yield" , therefore in an accident it absorbs more energy from the crash ,protecting the occupants better than say something of the same
structure in steel . Thats why those deformable structures ( ie ally radiators) at the front of such speciall vehicles do there job admirably .
After the locost club meeting last night im getting some really supportive comments - so keep em coming .
www.dbsmotorsport.co.uk
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andylancaster3000
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| posted on 14/12/04 at 05:02 PM |
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quote:
Originally posted by Staple balls
mon·o·coque n.
A metal structure, such as an aircraft, in which the skin absorbs all or most of the stresses to which the body is subjected.
Does it have to be metal?
Andy
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Volvorsport
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| posted on 14/12/04 at 05:11 PM |
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i dont think it has to be , of course when that description was about - it probably only applied to metal structures
www.dbsmotorsport.co.uk
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krlthms
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| posted on 14/12/04 at 05:38 PM |
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quote:
Originally posted by Volvorsport
i dont think it has to be , of course when that description was about - it probably only applied to metal structures
Most likely spruce, canvas, and shilac (e.g., spitfire wings).
Another name used for car is unibody. First to use in the Citroen Traction Avant (~1930).
I still think that what you are talking about is semi-monocoque, since you are going to be using metal subframes fore and aft. A true monocoque would
not have subframes.
Very exciting though.
Cheers
KT
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Volvorsport
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| posted on 14/12/04 at 05:42 PM |
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well , i know the citreon was early , but the lancia in1924 was the first of any monocoque design .
www.dbsmotorsport.co.uk
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krlthms
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| posted on 14/12/04 at 08:53 PM |
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quote:
Originally posted by Volvorsport
well , i know the citreon was early , but the lancia in1924 was the first of any monocoque design .
I, sir, bow to your superior historical knowledge.
Now, get off the f...ing computer, and start sketching.
Cheers
KT
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