Aluminium AC Cobra Chassis

[WKB]

Came across these photos which looks like an aluminium chassis for an AC Cobra



Warren

[stephen low]

Hmmm.....that would be nice............and light!!!

[sambo]

And brittle with age?

[albanycobra]

Wow that looks good.....

[Aussie Mike]

Looks like he's welding it with a MIG. I reckon there must be a lot more to it to stiffen up the front end. It'll be interesting to see how it develops.

Looks like it's right hand drive. Is it someone in Aus? There's a Falcon ute in the street.

Cheers

[400TT]

Originally Posted by sambo

And brittle with age?

Your kidding right? If they know what they are doing, they won't have any problems. It's all about using the right design, right materials and right manufacturing/production techniques.

Not a Cobra chassis, but I'm happy to share the aluminium love.

[albanycobra]

I guess if / when one of these alloy chassis cars gets registered and does a few years on our rough roads we will all know if they will do the job.

[sambo]

Originally Posted by 400TT

Your kidding right?

Craig, we're not all coach builders!

[400TT]

Fatigue testing is a good idea.

Then for good measure produce an incredibly stiff chassis. The chassis I posted above(without roll cage) is many multiples stiffer than registration requirements, even here in QLD.

[Jac Mac]

Originally Posted by 400TT

Fatigue testing is a good idea.

Then for good measure produce an incredibly stiff chassis. The chassis I posted above(without roll cage) is many multiples stiffer than registration requirements, even here in QLD.

Not that any kit car is probably a good thing to have a major prang in, but I often look at chassis like this and try to visualise which way the panels would deflect in a serious head-on type road prang, the Cobra chassis in the first post has inner guards that could fold back like a guillotine if hit in the right spot, although it appears that the front X-member is going to be bolted in at multiple points. The GT40 chassis I would hope might deflect up & back into the dash area to act as an energy absorbing area rather than retaining its shape & giving the occupants a serious jolt. Might have some sore toes afterwards though.

[cdnus]

Looks like they are real serious about it, there is another sitting on the trailer in front of the one being welded.
Just like Kirkham---you can't build just one.

Craig

[stephen low]

Dave

A curiosity question from one that know's little on the science but isn't the suspension operation a variable you can't factor for, hence why a chassis's twist is measured?

Can understand the leverage starting at the wheels but you have a moveable linkage to the chassis to allow for, so can you really measure at the hubs with fixed suspension and replicate actual twist reality?

I'm keen for a little enlightenment.

Cheers

[Hemo84]

G’day all, new to this forum and looking for some help.
Did anyone find out who was building the Alloy chassis in these pics? I would like to get in contact with them as im wanting to get one built.

Thanks in advance
Dan.

[400TT]

Dan, that chassis is manufactured by BDM (ByDesign Motorsports). Gary Hall runs the show and is a great guy.

We also manufacture aluminium chassis units for our kits, but take a totally different approach to BDM on our Cobra replica chassis.

So plenty of variety on offer.

[Hemo84]

[quote=400TT;1247810]Dan, that chassis is manufactured by BDM (ByDesign Motorsports). Gary Hall runs the show and is a great guy.

We also manufacture aluminium chassis units for our kits, but take a totally different approach to BDM on our Cobra replica chassis.

Hi Craig thanks for your input, I also have looked at you design, and am very impressed. I also find it refreshing to hear your comments about your opposition as I work in an industry where people aren’t so kind toward one another.
Can anyone tell me if the alloy bodies are available in Australia? Im not a huge fan of fiberglass as I work with aluminium for a living.

Cheers Dan.

[Aussie Mike]

I think it makes sense to do it that way. All the twisting loads the car will experience on the road are transmitted through the suspension.

Nice jig setup Dave. Well designed and though out.

Cheers

[LoBelly]

I think that plate aluminium is an excellent choice for a chassis.

I helped my brother put together an ally boat - very light and strong - and a great material to work with (pity I can't weld really )



Having used (or helped with) this material I am not surprised to find it being used for Cobra Kits - the chassis will look a little different but I anticipate they'll turn out very rigid and light.

LoBelly

[Hoofa]

Albanycobra,

That's a pretty cool test rig. Here is mine, I invested $4 into it for the lag bolts to fasten it to the floor. Everything else was kicking around the shop. It's not on the lift, it is sitting on angle iron placed under the shock mounts. Bouncing the weights was a great tool to see where the chassis was flexing.

[stephen low]

So the real question is that with all these specified torsional test parameters is there a standard rig specified?

I work in an industry with NATA test result requirements, ie standard specified testing parameters, which means that within fine limits, tests should be reproducable by any lab, is there the same standard of expectation for torsional twist testing?

Sounds like there is not or am I wrong?

[albanycobra]

I would question your test rig in that the pivot point is below the chassis at front and therefore as you apply load that you are not going to get a true torsion only result. If you were to break down the chassis to simple form the lower plane of the chassis is simply being twisted as its at close to the pivot height, but the upper plane of the chassis is being subjected to a parallelogram type load. If you were to raise the front pivot point you might find you get even higher test results than your current readings as many chassis simply have heavier material in the lower frame rails which would now be subjected to the parallelogrm effect as well..

JACMAC you need to read the NCOP12.LT (National code of pratice) test procedures.. There you will find that the machine in question is set up and tests the chassis exactly as per Government guidelines. Yes they have pictures.

http://www.infrastructure.gov.au/roa...s_3Feb2006.pdf

Maybe the machine does not make sense but that is how they want the chassis tested. My guess is they started like that and now keep it the same so apples can be compared with apples.