I am a clutz at the computer and could not figure out how to make the photos larger and still get the site to accept them. I will keep trying. My web site has larger ones
www.dragonmotorcars.com. Click on C5 Cobra to see everything.
Good question about aluminum fatigue cyle. I honestly don't know. I based my design and material specs on Herb Adams aluminum chassis that was available in the 90's. He was a pretty famous chassis engineer at Pontiac and wrote a book on chassis engineering. I have a GM chassis engineer that is finishing up one of my Dragons. I will ask him direct me in how to have the chassis evaluated for this and will report my findings. My frame is constructed of 100% T6-6061 material. It consists of a space frame that is constructed of 2X2 3/16 and 2X4 1/4 tubing. All of the shear panels and trans tunnel is from 1/8 sheet. The suspension pickups, lower are from 1/2 and is machined so that the stock Vette concentric alignment system is maintained. The upper control arm mounts are 3/8 in front, 1/4 in the rear. The front and rear clips are 1X1 and bolt on. They are designed to give before the main chassis. There will be 1X4 side impact beams with frame mounted stops that mount to the inside of the door. These will double as arm rests.
I do not use spot welds. Except for the floor which is MIG welded, the entire car is TIG welded. All of the panels are continously welded on both sides.