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Old 02-15-2008, 10:16 PM
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David Kirkham David Kirkham is offline
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Join Date: Mar 2001
Location: Provo, Ut
Cobra Make, Engine: Kirkham, 427
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Lew,


Bert,

Just put the hubs in the oven. They come out looking like gold...about as expensive too!

What'saCobra hits the nail right on the head! (But he cheated, he came out here and saw us sweating over it!)

BILLET ALUMINUM CHASSIS!

If you take billet far enough, you eventually just billet the chassis so you can get the suspension points where you want them.

The 90 inch wheel base presented some real challenges. The structure is very similar to a wing with longerons. We will rivet sheet aluminum over the billet rails.

Just for some fun information, we did an FEA (Finite Element Anaylsis) on the original 427 Cobra chassis and it had a stiffness of 1450 foot pounds/degree of deflection. The billet aluminum chassis we engineered has a stiffness of right at 4500 foot pounds/degree of deflection--or a 300% improvement over an original. Just for comparison, the thicker frame rails we use have a stiffness of 1650 foot pounds/degree of deflection--for an improvement of around 14% over an original chassis.

Interestingly, even so low a figure as a 14% increase in stiffness is READILY noticeable as soon as you drive down the road. I can't wait to try a 300% increase in stiffness! Another point of comparison, a "Supercar" (like a McLaren F1) typically has a stiffness of 10,000 foot pounds/degree of deflection--but remember, they have a roof which is an enormous help. We were able to get the stiffness of the billet chassis so high because we used very tall door sils that we hid under the doors and spread them WAY apart. We also made a really cool billet aluminum bulkheads and a stressed tunnel to help transfer the loads.

David


I will post a picture soon.
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David Kirkham, President Kirkham Motorsports
Manufacturer Aluminum Body Kit Cars and supplier to Shelby* for their CSX4000, CSX7000, and CSX8000 289 and 427 Cobra
*Kirkham Motorsports is not affiliated with Ford or Carroll Shelby or any of their trademarks.
"Fear is the thief of dreams."

Last edited by David Kirkham; 02-15-2008 at 10:19 PM..
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