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Section chassis
kango - 31/8/06 at 06:26 AM

What will be the conserns to build the chassis in 3 sections. The engine, the cockpit and the rear and then bolt them together.

The advantahes I see is:
1) If in an accident one can undolt the section that is damaged, built a new one and bolt it back on
2) during the manufacture process the smaller pieces are easier to handle and take up less space in the garage
3) Better welding - as the smaller pieces can be turned easier to optimise the welding position.
4) the joints can be designed to allow some adjustment after the welding process

What would be the best way to join the pieces?


SeaBass - 31/8/06 at 06:49 AM

quote:
Originally posted by kango
What would be the best way to join the pieces?


Weld them??

Seriously I doubt that a removable mechanical joint on such a small area would work. It could be prone to failing and would be nowhere near as strong as continuous tube.

Cheers

[Edited on 31/8/06 by SeaBass]


nick205 - 31/8/06 at 07:08 AM

As an example, the Jaguar E-Type (and probably other cars) uses a combination of monocoque body tub with subframes bolted to the front to form the front of the chassis. The mounting points on both the monocoque and subframe parts use large plates to space the bolts apart and spread the loads. They also bolt together over 2 different planes (horizontl and roughly 45 deg) to further spread the loading effects.

IMHO you would need to make major alterations to a locost style chassis in order to achieve a stiff and strong enough structure. Personally I wouldn't attempt this without some proven design experience. I think you'd be better to build your chassis in the "normal" way.


smart51 - 31/8/06 at 07:15 AM

Are you planning to crash it so often that removable parts are needed?


MikeR - 31/8/06 at 07:23 AM

Staniforth talks about how he made one chassis in the past with two roll bars. These where next to each other with one being from the cockpit side and one from the engine. The whole chassis spilt in two at this point and the roll bars had lots of bolts through them to hold the car together.

I've wondered in the past about designing a midi that had universal middle section with bolt on front and rear sections. Never did anything about it mind you.


ned - 31/8/06 at 07:28 AM

a lot of racecar tubs/spaceframes stop at teh bulkhead behind the driver, then subframes support the engine etc, this is even more often the case where the rear suspension hangs off a rear transaxle, it also allows different engines/subframes to be fitted to the same design tub with the same mounting points.

Ned.


JoelP - 31/8/06 at 07:28 AM

The idea has merits. You would add some weight though having plates welded in to bolt them together via.


ned - 31/8/06 at 05:07 PM

Probably didn't make it very clear but in the above thread I was referring to mid engine inline with transaxle behind.

Ned.

i vaguely recall a thread literally years ago - an idea merlin had called the magic box iirc basically a front chassis section you could produce and sell that would have all the front suspension points fully jigged onto. the idea at the time was to make fu1 & 2 easier I think.

pps found it:
http://www.locostbuilders.co.uk/viewthread.php?tid=1318

[Edited on 31/8/06 by ned]


Peteff - 31/8/06 at 06:48 PM

Whatever will they think of next? . It's just like having a front and rear subframe carrying all the engine and suspension mounts and a body to mount it all to. Of course it's a good idea, that's probably why all the big manufacturers use it. Even robots could do it.


kango - 1/9/06 at 04:07 AM

So where are the engineer types that can come up with where the joints should be and how they should look to retain the structural integrity of the LOCOST?

Another advantage is if one would start with say the rear end and realy battle to get the IRS sorted it would be a much cheeper project to can than having a whole frame.

Also upgrades/experiments would be possible.


locostv8 - 1/9/06 at 07:23 AM

quote:
Originally posted by Peteff
Whatever will they think of next? . It's just like having a front and rear subframe carrying all the engine and suspension mounts and a body to mount it all to. Of course it's a good idea, that's probably why all the big manufacturers use it. Even robots could do it.


Then the first thing that MUST be done is add a cage and subframe connectors to stiffen up the chassis enough to make it useable.


kango - 2/9/06 at 04:36 PM

So where do you split it and what does the joint look like.

Bolt and dowl and what size bolts, how many......


DIY Si - 2/9/06 at 04:42 PM

I'd suggest 3 parts. From the footwells forwards, baclwards from the rear bulkhead, and a central passenger tub. Not too sure as to what mounts would be most acceptable, but you would need plates/mounts in at least 2 planes, prefereably at the corners. You would also need some fairly accurate way of locating everything so the suspension would be accurate/car wouldn't crab etc. Lugs/dowels are one way, another is to have sleeves for the bolts to go through and hold it all together, as per bell housings and similar stuff.


goin2fast52 - 2/9/06 at 07:53 PM

Steve Graber did it on La Bala. Check out www.grabercars.com for more details.