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Now here’s a gray area...
Mr Whippy - 30/7/08 at 10:20 AM

For the SVA what actually classify’s as a chassis, probably sounds a dumb question in relation to a 7 but it doesn’t seem too clearly defined. For example is a chassis a removable structure that the suspension must bolt to? If that’s the case then what happens if you then bond your GRP bodyshell to it, have you just made it unitary construction requiring a good old crash test i.e. not the SVA, I don’t think so. Even worse what if the chassis is there but it’s completely hidden inside the body shell like if it was encapsulated in a foam/GRP skin. What on earth kind of car structure would that be called, would it be an issue for the SVA?

Reason I’m asking is that’s precisely how I want to build a car so need to clarify the issue right from the start…

cheers


smart51 - 30/7/08 at 11:11 AM

You've got me thinking now. Steel tubes or bars joining the wheels and engine is obvious. DVLA / VOSA count a monocoque as being "the chassis". I guess anything welded to the monocoque is also the chassis.

If you make the structure of the vehicle out of a mixture of steel plates, tubes and foam cored GRP, then the whole thing becomes a sort of monocoque. That is unless the steel work is complete in itself and the GRP is merely bonded to it.

the old mini had a monocoque chassis with subframes mounted front and rear. I guess as they could be removed, the subframes weren't counted as "the chassis".

You could always ask the SVA section of VOSA the question. You'll get the right answer that way.

What construction are you thinking of using?


Dangle_kt - 30/7/08 at 11:15 AM

heres a grey area:





Agriv8 - 30/7/08 at 11:18 AM

not ans answer I know but a leading question How do GTM get on as that monocock and steel tube IIRC ?

regards

Agriv8


Mr Whippy - 30/7/08 at 11:31 AM

quote:
Originally posted by Dangle_kt
heres a grey area:






obvously my daftness is contagous...

GTM do have to do crash tests (they come out very well btw)

Even an alloy sheeted spaceframe like the 7 is aguably a unitary construction really as you can't unbolt the chassis can you...see what I mean about gray??

I was wanting to do a light weight roll cage affair with the engine/suspension bolted to that then encapsulate it in a streamlined GRP foam body shell.


smart51 - 30/7/08 at 11:43 AM

quote:
Originally posted by Mr Whippy
I was wanting to do a light weight roll cage affair with the engine/suspension bolted to that then encapsulate it in a streamlined GRP foam body shell.


You're just copying me aren't you?


Mr Whippy - 30/7/08 at 11:56 AM

well I'm wanting to do something like this, using an Ultima windscreen, my lambo mega wheels, a locost front end plus the back end of a 1200cc bike. Unfortunately I couldn't get that link you gave me to work so haven't seen your 3 wheeler


Mr Whippy - 30/7/08 at 12:04 PM

doodle doodle doodle....hmm Rescued attachment car3.JPG
Rescued attachment car3.JPG


smart51 - 30/7/08 at 12:16 PM

quote:
Originally posted by Mr Whippy
Unfortunately I couldn't get that link you gave me to work so haven't seen your 3 wheeler


Go to the 3 wheel section of this site, look for the thread "micro car chassis". My car won't look like the aptera. It is 3 wheeled with a foam / GRP body on a steel chassis, quite like yours.


ReMan - 30/7/08 at 12:16 PM

quote:
Originally posted by smart51

You could always ask the SVA section of VOSA the question. You'll get the right answer that way.



Are you serious?
Or is that just the DVLA?


[Edited on 30/7/08 by ReMan]


Mr Whippy - 30/7/08 at 12:47 PM

quote:
Originally posted by smart51
quote:
Originally posted by Mr Whippy
Unfortunately I couldn't get that link you gave me to work so haven't seen your 3 wheeler


Go to the 3 wheel section of this site, look for the thread "micro car chassis". My car won't look like the aptera. It is 3 wheeled with a foam / GRP body on a steel chassis, quite like yours.


oh yes I remember it now, I wait in anticipation to see its final shape got a drawing or something that your working too?

[Edited on 30/7/08 by Mr Whippy]


Dale - 30/7/08 at 04:59 PM

I was looking up an old trike from the seventies that was made using a foam/fiberglass shell and saw a new one on the site. It uses a Kubota diesel to run the front wheels and/or electric to run the rear. The body is not exactly to my taste but the idea is interesting and modular. Any idea on how much horsepower is required to cruise at 70 mph on say a 1200 lb car with a good drag coeffient.
http://www.rqriley.com/xr3.htm

there is the url.

Dale Rescued attachment xr3_headlight-3-b-m_resize.jpg
Rescued attachment xr3_headlight-3-b-m_resize.jpg


Ferg - 4/8/08 at 05:10 PM

quote:
Originally posted by Mr Whippy
GTM do have to do crash tests (they come out very well btw).

GTM have NEVER to my knowledge crash tested a car, or even a chassis.
The GRP monococque has proved very strong in the 'incidents' it has been involved in though....

For info, the chassis only has two 2" square pieces of steel in the top seatbelt mounts, otherwise it's pure GRP.


iank - 4/8/08 at 07:13 PM

You only need to crash test if you are type approving a car. SVA test is a bit suck it and see if you are making your own monocoque as RH found with the Lightweight as it's down to the testers 'opinion' of the suitability/safety unless you can prove him wrong.

Getting back to the original subject I'd classify a chassis as anything that is designed to have suspension loads fed into it. If a metal frame can be driven without a bonded on shell then then it's the chassis. If it needs the shell to be stiff enough to be driven then it's a monocoque IMO.


t.j. - 4/8/08 at 08:43 PM

quote:
Originally posted by iank
You only need to crash test if you are type approving a car. SVA test is a bit suck it and see if you are making your own monocoque as RH found with the Lightweight as it's down to the testers 'opinion' of the suitability/safety unless you can prove him wrong.

Getting back to the original subject I'd classify a chassis as anything that is designed to have suspension loads fed into it. If a metal frame can be driven without a bonded on shell then then it's the chassis. If it needs the shell to be stiff enough to be driven then it's a monocoque IMO.


I with you here!
A seven has a spaceframe which gets the loads. The alu-plating is only for the "looks"