Million Dollar Skunksworks Kirkham - Page 53

David Kirkham · #**1041** (**permalink**) 09-20-2009, 11:40 AM

The rear wheel well was the most difficult engineering problem on the car to solve. It almost stopped the project cold. Finally, we just decided to get a BIG billet of aluminum and start carving. I thought the quote from Hannibal was appropriate here, "We will either find a way--or make one." referencing his crossing of the Alps on the back of elephants. It is extremely difficult to stop someone who is determined to succeed.

David Kirkham · #**1042** (**permalink**) 09-20-2009, 11:41 AM

The problem lies here: The driver's head actually sits BEHIND the leading edge of the rear wheel. In most cars, the rear suspension "pushes" forward on the chassis through a straight bulkhead. This makes it very easy to design the chassis. You simply connect the rear suspension to the rockers at a 90 degree angle and that's it. The wheelbase is extremely short in an original car--only 90 inches. This leaves very little room for the chassis (and makes the driver actually lean OVER the rear tire). I bet you all didn't realize how close that tire really is!

David Kirkham · #**1043** (**permalink**) 09-20-2009, 11:45 AM

So, we bought a BIG billet of aluminum, cut it in half on the bandsaw...

David Kirkham · #**1044** (**permalink**) 09-20-2009, 11:48 AM

We welded some blocks of aluminum onto the sides of the 1/2 round we made so we could space the chunk of aluminum away from the mill. The blocks were cut off in the machining process.

David Kirkham · #**1045** (**permalink**) 09-20-2009, 11:50 AM

The part was a beast to make. We had to make it will all 4 axis of the machine moving at the same time to avoid the part hitting the mill. The shiny circles were left by a drill. Drilling is the fastest way to remove a lot of material.

David Kirkham · #**1046** (**permalink**) 09-20-2009, 11:52 AM

We started out with a block of aluminum that weighed 147 pounds. The final parts weighed 3.82 pounds each. About 95% of the aluminum was machined away to make the part. The parts were quite stiff and extremely light when we finished.

David Kirkham · #**1047** (**permalink**) 09-20-2009, 11:58 AM

Here the rear wheel well panel is bolted into place. Notice the stainless steel bolts. This is the delivered chassis.

This is a nice shot to show how we connected the rear bulkhead to the rockers.

David Kirkham · #**1048** (**permalink**) 09-20-2009, 12:00 PM

The funny flat milled into the part is for seat clearance. Everything is quite tight in the car. Also, notice the hefty seat belt mounting point just in front of the wheel well.

David Kirkham · #**1049** (**permalink**) 09-20-2009, 12:02 PM

I'll post more soon!

Happy to answer any more questions. Please don't be afraid of offending me! There are a lot of smart guys on this forum and I am sure there are things we could have done better! I'd love to hear any suggestions.

David

acindrich · #**1050** (**permalink**) 09-20-2009, 10:54 PM

Quote:

Originally Posted by David Kirkham

I'll post more soon!

Happy to answer any more questions. Please don't be afraid of offending me! There are a lot of smart guys on this forum and I am sure there are things we could have done better! I'd love to hear any suggestions.

David

OK - you're ugly. And your machinist is ugly too!

Hexnut72 · #**1051** (**permalink**) 09-22-2009, 08:53 AM

Quote:

Originally Posted by acindrich

OK - you're ugly. And your machinist is ugly too!

At least they know better than to wear socks with sandals.

acindrich · #**1052** (**permalink**) 09-23-2009, 07:49 PM

Quote:

Originally Posted by Hexnut72

At least they know better than to wear socks with sandals.

C'mon, I'm sure socks with sandals is en vogue somewhere.

MOTORHEAD · #**1053** (**permalink**) 09-23-2009, 08:20 PM

WoW !!!!!!!!!!!
All that shiny machined aluminum ! Looks more like pieces for a high-tech military fighter, like a MIG maybe !! David, you've come full circle !!!

Maurice Butler · #**1054** (**permalink**) 09-24-2009, 02:05 AM

Great thread - I have download your book and have been reading it - talk about setting the bar high for the quality builds

David Kirkham · #**1055** (**permalink**) 09-25-2009, 05:21 PM

The footboxes had to tie everything together. Angles everywhere. They were a beast to figure out. That is why I chose Heinlein's quote here.

David Kirkham · #**1056** (**permalink**) 09-25-2009, 05:23 PM

Quote:

Originally Posted by MOTORHEAD

WoW !!!!!!!!!!!
All that shiny machined aluminum ! Looks more like pieces for a high-tech military fighter, like a MIG maybe !! David, you've come full circle !!!

I never thought about it that way. I learned how to machine by standing by some incredible machinists and watching them transform blocks of metal into beautiful parts. Today, we do that with CNC machines.

David

David Kirkham · #**1057** (**permalink**) 09-25-2009, 05:25 PM

I thought the gold heat shield added just the right amount of color to the project.

David Kirkham · #**1058** (**permalink**) 09-25-2009, 05:35 PM

In the prototype car we tapped the holes by hand on many of the parts. For the final car, we wanted everything to be perfect, so we make more fixture plates to hold the parts at the right angles for drilling and tapping. Maybe one day we will get a 5 axis mill.

rodneym · #**1059** (**permalink**) 09-25-2009, 05:35 PM

I thought that was Kapton foil.
With all those angles it kind of looks like the LMs.
You've got some incredible materials in that thing...

David Kirkham · #**1060** (**permalink**) 09-25-2009, 05:40 PM

You can see the Ford GT in the background. We put a Ferrari 430, Ford GT, Dodge Viper, Corvette ZO6 (I don't remember what all else) on the lift for inspiration.