Million Dollar Skunksworks Kirkham

[lineslinger]

My comments were not meant as a suck up, craftsmanship is always to be noted, if your customer starts to pick it apart I would like to discuss the project with you..no BS.

[David Kirkham]

Originally Posted by lineslinger

My comments were not meant as a suck up, craftsmanship is always to be noted, if your customer starts to pick it apart I would like to discuss the project with you..no BS.

My customer has really been one of the nicest men I have ever dealt with--maybe even the nicest. He has never nit-picked anything I have done. On the contrary, he has been quite complimentary...the funny thing is, the more complimentary he is, the more I want to make the car even better just so there is no possibility I could let him down. I am just nervous, that's all; I really don't even know why, I just am.

David

[David Kirkham]

This is a really interesting part. This is the pedal box. On the original 427 Cobra, the master cylinders for the brakes and clutch is under the floor. My customer told me one day he wanted to drive this car down the PCH from San Francisco to LA. One of the problems with the original car is you can't slide your foot under the brake pedals because they are floor mounted. We thought a lot about this and decided to hang the pedals from the top.

The problem is; if you hang the pedals from the top, they are right above the exhaust and they will "pre-heat" your brake fluid for you! Bad, very bad--especially if you are facing turn 1 at the end of the straight and you already have your brakes hot. So, we flipped the master cylinders around so they face the driver and the brake pedal turns into a class 1 lever (just like a teeter totter). It made things tight, but it was the only answer that worked.

[David Kirkham]

Notice in the above box we made 2 internal supports for the pivot pin. The stiffness of the pedal box is critical to brake feel. You do NOT want your brake pedal or pedal box flexing! You do not want anything in the brake department flexing as it gives the driver a vague feel of what the brakes are doing. Flex makes modulation of the brakes impossible (or at least very difficult). So, we placed intermediate braces in the box--between the brake and clutch pedal levers--to mitigate any flex that could creep into the system. Also, the front of the foot box is made from 1/2 inch aluminum plate. The top of the foot box is made from 1 inch plate! (All hogged out and lightened up, of course.)

[David Kirkham]

Here are the brake and clutch pedals.

You can see we designed them so there is clearance for your toe as you work the pedal. We designed the pedals straight so there would be no chance of the pedal flexing under hard braking. The original Cobra brake and clutch pedals are bent to put them in the right place for the driver to use them. The bend in the pedals is weak spot that causes the pedals to flex. That was a problem we had to solve in this car.

So, we placed the pedals optimally in the foot box for the driver, but that caused problems lining up the pedals with the master cylinders as the pedals are nowhere near directly under the master cylinders. So, we machined the offset into the top of the pedal--along the axis of the pivot pin--thereby eliminating any side loading of the pedals or the master cylinders.

The down side is the billet to make the pedals was 4 x 2 x 20! That is 16 pounds of billet! The finished machined pedals are just over 1 pound each.

We have been asked many times how much of the billet goes into chips. I would guess on average 90-95% of the aluminum billet goes into the chip barrel. Aluminum does recycle, however!

[David Kirkham]

Oh yes, in the above picture, the brake pedal is on the right; the clutch pedal is on the left.

[David Kirkham]

This is a close up of the top of the brake pedal. This is where the brake bias bar attaches to the brake pedal. The hollow cylinder holds the bias bar bearing. When we put the bias bar in the car, I will take a pic. As you can see in the picture, the bias bar itself is also supported on the pivot pin to absolutely minimize any flex in the system.

[lineslinger]

Originally Posted by David Kirkham

My customer has really been one of the nicest men I have ever dealt with--maybe even the nicest. He has never nit-picked anything I have done. On the contrary, he has been quite complimentary...the funny thing is, the more complimentary he is, the more I want to make the car even better just so there is no possibility I could let him down. I am just nervous, that's all; I really don't even know why, I just am.

David

Keep the slide show active, I enjoy the visuals............

[David Kirkham]

Originally Posted by lineslinger

Keep the slide show active, I enjoy the visuals............

My fingers are hurting from all the posting and emailing I have done today. I will definitely post more tomorrow. Maybe after I play a few Chopin Nocturnes my fingers will limber up and then I will post a few more pics. But thanks for the interest! I am glad you like it. I hope others like it too and I don't think I am being a big mouth by monopolizing the CC band width.

David

[David Kirkham]

What the hey, I'll post another one.

This is a pic of the belly pan. This is the real secret why the chassis is 300% (at least that is what the FEA says) than an original chassis. The belly pan ties the entire chassis together on the under side. Also, it is the area that is the furthest from the neutral axis of the chassis. As many of you know, the farther you can move the mass from the neutral axis, the stiffer the part will be.

The belly pan was cut out on our water jet from 1/8 inch aluminum plate. It also has the added benefit of cleaning up the under carriage air so the car is more aerodynamic--although I don't think that is a major concern with this car.

[David Kirkham]

Oh yes, the cut out on the top is to clear the bell housing. The belly pan runs from the engine all the way to the differential. The weakest part of any Cobra type chassis (open car) is the area of the cockpit. The low cut out for the doors makes the chassis flex in the door area. That is why many old Cobras that you look at have cracks under the doors. The original frame rails were pathetically thin and flimsy.

Now I will go and play Chopin's Nocturne Opus 27.2. I hope Chopin doesn't roll over in his grave.

David

[David Kirkham]

I do have a nice piano, but one day I would like to get a European piano like a Steingraeber, Fazioli or a Bosendorfer. But with the Euro exchange rate like it is I don't think I will ever be able to justify it!

David

[saltytri]

Originally Posted by David Kirkham

I hope others like it too and I don't think I am being a big mouth by monopolizing the CC band width.

You've got to be joking, pal! Since you launched this extravaganza of a thread, it's the first thing I go to when I sit down at the computer. Just keep it coming, please.

[David Kirkham]

Originally Posted by saltytri

You've got to be joking, pal! Since you launched this extravaganza of a thread, it's the first thing I go to when I sit down at the computer. Just keep it coming, please.

Ok, one more.

[David Kirkham]

Here you can see we got the engine firewall installed in the car. If you look closely you can see some of the zillion bolts going into the chassis.

[lineslinger]

Originally Posted by David Kirkham

My fingers are hurting from all the posting and emailing I have done today. I will definitely post more tomorrow. Maybe after I play a few Chopin Nocturnes my fingers will limber up and then I will post a few more pics. But thanks for the interest! I am glad you like it. I hope others like it too and I don't think I am being a big mouth by monopolizing the CC band width.

David

I think Mr. Chopin would appreciate your work.

[David Kirkham]

Originally Posted by lineslinger

I think Mr. Chopin would appreciate your work.

I can only dream he would. He was a genius. If my work were ever uttered in the same sentence as his work I'd be proud (probably more like shocked!). He will be one of the first people I will search out when I go to the Great Race Track in the Sky. I just want to know how he did it.

Interestingly, my customer once told me, "Music is man's greatest invention." I believe him.

David