McCann Chassis

D Sports Racer

John McCann
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Static Skip Pad

John explains this interesting image: 

"When designing the McCann ME-4 DSR, I realized that if you tilted a car at 45° you would start to simulate a 1G side load (on a flat track) as both the normal loads (into the tilted plane/track) and side loads would be equal, but only 71% of their true values (.707 X 1G). However if you added 1.414 X the car's weight - divided into the front and rear axle weights, via an external load passing thru the front & rear axle CGs (the vertical cables in the photo) you would then have normal and side loads of .707 x 1.414 = 1G!

Now, if you added normal external loads, also thru the front and rear CGs, you could simulate the effects of aerodynamic down force (the angled cables in the photo)! The minor effect of the tilting moment of the unsprung mass, notwithstanding. The usefulness of the invention was shown when my original front roll bar was too small (due to a calculation error). We placed a bathroom scale w/a side load limiting strap under each wheel to check the wheel loads under the 1G simulation. 

BLAL (Before Large Aerodynamic Loads), typically a car, at the maximum, cornered on three wheels (the inside, non-driven wheel should have zero weight) as to transfer all inside weight to the inside driven wheel to accelerate out of the corner).

I received US Patent # 4,238,959 on this invention: http://patft.uspto.gov/netahtml/srchnum.htm [enter 4,238,959]. I had planned to replace the turnbuckles with calibrated pneumatic cylinders and turn the crude prototype into a portable device to provide a track side service. However, for personal reasons, I soon got out of racing, to resume a more normal family life (I became an avid gold prospector and had a profitable home business for 14 years based on another patent!).

As an aside, I found out that while an engineer is designing a race car you have the kind of respect you might imagine… but as soon as the car hits the track, "other experts" come out of the wood work and my voice was soon lost in the wind. Now, having read several books by famous racecar designers of the era (Costin, Terry, etc,), I found out that this is very common place!"