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chassis regs / sva
oadamo - 8/3/07 at 09:06 PM

hi i am starting to build my own chassis but iam going to use the seats as part of the chassis. so the seats and chassis are fabricated as one all out of alloy and then a seat liner will be fixed to sit on . but does anyone no if this is ok. wot do i need seat belt wise. i want the belts to go in 4 holes throw the seat but wot sort of anchor points do i need for the sva. i was thinking that when i put the belt throw the hole i could put a bar throw it and fix to a reinforcement plate fixed to the back of the seat
thanks adam


flak monkey - 8/3/07 at 09:09 PM

My first question is, and its not a dig, do you know what you are doing when it comes to chassis design?

Especially if you are making what sounds like some sort of aluminium monocoque. Attachment of load bearings points is a major concern in any type of chassis construction. There is some rough guidance in the sva manual. But not too much.

Have you got any sketches/drawings/cad models/whatever?

David


oadamo - 8/3/07 at 09:17 PM

theres only one way to find lol on the load bearings points iam gonna brace them across the chassis cus how ive designed it you cant so most of it that will be braced. iam trying to keep a clean look on the out side and when you look in the car.ive got some sketches but they look like there done on a etcha sketce kid thing. iam gonna build the tub bit where you sit first then add the front end and then the back to it if you no what i mean
adam


nitram38 - 8/3/07 at 10:30 PM

Have a look in my archive.
My car has no front seat. My seating position is chassis and aluminium with 1/2" foam glued on.
Passed just fine.
Make sure that you locate your seat belt anchors (I used bushes that were welded both sides of the box section) as close as possible to points where the chassis intersects. These are the strongest points.
Remember that in an accident, your body will suddenly put forces of several tons on these mounts.
Don't be put off. I reckon that when you stand back from your creation, you will realise how over engineered that you have made it !!!!!


andyps - 8/3/07 at 10:49 PM

Nothing to do with SVA, but just ensure you consider what is between you and the ground whilst building. I seee to remember that the Arial Atom was due to have just a GRP seat on the chassis frame until they realised where something like a brick which was laying on the road might stike the driver


02GF74 - 9/3/07 at 08:25 AM

what contingency do you have for adjusting the seat should it happen to be too far forwards or too far back?

Seat belt anchorage points need to be 450 mm above the seat base.

I think there is also a figure on how far apart they must be in the SVA book.


nitram38 - 9/3/07 at 10:57 AM

quote:
Originally posted by andyps
Nothing to do with SVA, but just ensure you consider what is between you and the ground whilst building. I seee to remember that the Arial Atom was due to have just a GRP seat on the chassis frame until they realised where something like a brick which was laying on the road might stike the driver


The arial still has a fibreglass floor (high density) along with most of the newer TVR's. The seats are attached to a subframe
You can see the subframe in this upside down arial chassis:


oadamo - 9/3/07 at 11:48 AM

i think the best bet is for me to buy an sva book because i bet theres a lot of things i dont no about when i start welding it togrther and i dont want to have to start pilling it apart to put things right because it will start to look a mess.
i was gonna have the steering wheel ajustable the seat will be in a fixed position and cuz iam making it to fit me i shouldnt need to adjust it


Gav - 9/3/07 at 12:47 PM

http://rootpeg.net/SVAMarch2004.pdf