When building chassis from scratch or kit form, we need to be very careful
to follow the SCTA/BNI structure requirements. I have a lot of Mark
Williams parts in my new lakester (streamlinerwannabe), and feel the quality
of parts and material from MW is quite appropriate, but, wall thickness and
tube diameter of the kits does not meet our safety requirements. For the
most part we require a very ridged structure which means larger diameter
tubing and thicker wall sections as well as lots of tri angulation to
distribute loads.
As grotesque as it seems, I am planning and building while asking the
question, "what is going to happen when I go on my head at 275 MPH? (or more
:=d )
I have spoken with a number of my engineer buddies at Fraud Motor Co. that
are specialists in computer modeling (FEA) and while we could model the
chassis and predict the way the chassis will deflect or deform in a crash.
The difficulty in trying to do this is predicting the direction of impact,
and then the second impact, third, fourth, etc...and how deformation occurs
at each hit. No data exists that will show us what the forces are
progressively.
I suppose with enough computer time it may be possible, but no one was
willing to take it on. My point is then that we must build for the "worse
case".
Please don't think that I am an expert in this safety business, or the
ultimate structure. Just offering my observations and thoughts.
After working with SAE 4130 tubing on my new car, I will not use anything
else in the future. The cost is not much higher and it even welds so much
easier.
Rick Byrnes
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/// what is needed. It isn't that difficult, folks.
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