18 May 2008

I had a professional Mechanical Engineer look over Midlana’s CAD drawings who gave it a thumbs up. He made a couple of good observations which I’ll incorporate. He shares my irritation with the SCCA rule that allows using 1.375″ x 0.080″ rollcage tubing – which can be neitherĀ found norĀ bent!

7 May 2008

A generous reader, Matt, volunteered to run my CAD chassis through FEA (finite element analysis). The chassis has already changed since last week and will probably change more, but knowing its approximate stiffness is helpful. The center tunnel has already changed, too, now a 4″ wide x 12″ tall affair with about 5000 ft-lbs torsional rigidity.

The pictures are of last Saturday’s Irvine car thing. Notables were the 1970 Porsche 917 and that crazy Nash Metropolitan with its big-ass engine. It was like a giant leaf blower when he drove in, the bottom-exit pipes blowing dust everywhere. With the idle surging up and down it made simply driving through the lot a chore. Amazing that he drives it on the street! Of course I suppose he could say the same of me. On the way out I couldn’t help but get a shot of Kimini next to it.

Not related to the Nash – really – I verified that Kimini’s top speed is 127mph, gear-limited. It was still accelerating pretty well so I’m guessing perhaps 135mph aero-limited, which means the drag coefficient is lower than expected. I’m happy. (Early Saturday mornings the freeway is pretty empty; I didn’t pass anyone during this test and endangered no one but myself.)

29 Apr 2008

A surprising number of people wrote to say that I made the car too short in wheelbase. I’m not sure why they think that since I haven’t supplied any numbers. I think it’s due to the wide track, making the car look short. Anyhow, it’s a 100″ wheelbase and a 60″ track. Guess I need to create a Specifications table somewhere…

About the torque tube, it doesn’t seem very popular, plus I may have miscalculated the stiffness. Regardless, the shifter’s got to mount somewhere, as does the e-brake lever. Then there’s all the control cables, wires, and coolant lines. If the tube is deemed useless, where does all this stuff go?