Volume IX, Issue 4, Page 70

4/19/2007


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ENGINEERING QUESTIONS

As a graduate Mechanical Engineer I couldn't agree more on your chassis design comments. I would think that a thorough finite element analysis of the current chassis designs would be in order if not already done. Also, larger diameter, thicker wall tubing, and additional bracing should help while not adding a tremendous amount of weight. This would also help slow the cars down.

While we're at it, how many of the other classes have chassis and suspensions that are being severely overloaded? This seems to be a situation based on experience (i.e. this has worked without breaking, let's use it) versus real design efforts (design it, build it, pre-race test it). 
Tom Ales
Larsen, WI

CLARIFICATION

I would like to clarify some of my points in my note to you posted on April 5. From an engineering point of view I should have said that welded structures of 4130 that are to be heat treated must be heat treated after welding, not before. As to the dragster chassis that have broken since the Schumacher chassis failure in July 2005, all have been built in the Murph [McKinney] manner with tubing heat treated before welding. SFI does have a provision for non-heat-treated tubing but because of their incorrect calculations, there is a weight penalty.  Errors in the SFI calculations were called to their attention and then they did a cover up. 

The active SFI Funny Car Chassis spec 10.1 E, requires Normalized SAE 4130. Murph is building his funny car chassis with heat-treated tubing.  This is a violation of the rules. Strange that SFI and NHRA choose which rules to apply.  Since we know that the heat-treated dragsters have a problem breaking will the same happen with the funny cars? Or maybe it has already happened.

I don’t want to sound like a pessimist but there are some very troubling issues here. Unfortunately, it may take a wrongful death lawsuit to get the real facts out in the open. Maybe it can be resolved without a lawsuit if people ask the correct questions and demand a full and truthful answer from those charged with the responsibility of keeping drag racing safe.
Robert Daniel
Wyoming

STRESS SAFETY

As to your question: how many teams have real engineers on board? You could ask how many the NHRA has. Or SFI. The situation regarding the safety of TF and FC cars is dangerous, the cars just have such a small factor of safety that it doesn't take much to create an accident. Many in the sport think it is manly to face danger in such cars. Meanwhile the rest of the motor racing world has embraced safety as a way of keeping their sport viable.

By the way, I like the idea of 1/8-mile drags. Those I have been to are inevitably much more interesting with more "races per hour" than the 1/4 mile drags.
Don Pepper
Carlsbad, CA

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