I think that in this case the proper course of action would be not to try to fix it if it ain't broken.
This is not to say that SCTA and others should not be continuously reviewing their rules as speeds increase and to review each and every incident to find out the causes. They have to be seen as showing due diligence to protect themselves. But they shouldn't make changes unless those changes can be shown to make our vehicles safer.
Tom
That just might be the point the SCTA was trying to make. Why do we allow different tubing sizes for vehicles that travel the same speed? Some demented legal eagle might just ask that question if something happened right now, maybe?
"Why do we allow different tubing sizes for vehicles that travel the same speed?"
Please don't treat this as a rhetorical question. Take it as a real question and sit still for a real answer. The answer is that there is a significant difference in weight between the two.
With all due respect to the accomplished racers and other thinking members of our sport..... I understand how many of you have career war stories of encounters with inexperienced and downright ignorant engineers. But it is time you opened your minds and listen to the small number of your lot that were trained as engineers and know a bit more about the laws of physics than you do. We have more and more LSR projects running over 300 and knocking on the door 0f 400 and very little practical engineering knowledge (born of analysis, tests or accident experiences) of what goes on up there.
"Speed kills" ........... Well is that so? Seems to me that you can travel all day long in a jet airliner at 550 mph without significant bodily injury.
No, it's energy that kills. When in the form of kinetic energy, which is in simple terms weight times speed squared, it has the ability to destroy human tissue if turned loose in a crash to find places where we don't want it to go. And the more rapidly that energy dissipates to heat the higher the forces involved.
A 5000 pound roadster has twice the kinetic energy at 200 mph as a 2500 lb lakester, 4 times that of a 1250 lb bike. In a crash situation non-aero energy get scrubbed off by the tires in a spin. But some combo of partly rectangular front aspect profile, high center of gravity, ground roughness or softness and tire failure can make it go airborne and quickly "roll up in a ball". Coupes/sedans add a fifth tendency to go airborne, their aerodynamics. The attitude of the car on landing has a lot to do with the duration of the impact with the ground. The shorter the duration the greater the impact forces on the cage.
Modern streamliners and narrow tread lakesters lacking the shape shortcomings of the stock body tend to "pencil roll". A more or less square front aspect profile is not going to roll as smoothly as a round profile. All other factors being equal "square" will scrub off kinetic energy faster but is more likely to bounce or otherwise depart from true rolling and accentuate the shock of a final stop.
At this point we look to the cage to protect the driver by neither crushing him or allowing parts of his body to get outside its "defense perimeter". But we also would like to see the cage have just enough flexibility to slow the application of forces from outside and thereby lessen the shocks and "g" forces to a point where the rest of the cushioning around the driver can do its job of shock isolation. And note that this "flexibility in the vehicle structure consists of both components that deflect and then spring back to their original shape and parts that are permanently deformed as well.
An important unknown to me is how important "springiness" or elastic deflection as we engineers call it in taking the peaks off of crash shocks pointed at the driver who is already surrounded by various "padding" structures and restraints. I somewhat suspect they are trivial, but suspicions, while they might provide paths for inquiry, do not make satisfactory results to an engineering analysis.
So back to kinetic energy. It is my feeling that gradiation in crash event protection built into our machines should be based on the expected kinetic energy and the potential rolling stability of the vehicle. The idea here being that the longer it rolls the lower the rate of energy disipation and therefore more moderate shocks to the driver instead of fewer severe shocks. But until we have more good engineering information on the subject we should be guided by what experience and knowledge we already have.
I still think there are lots of good engineering research projects here, both undergraduate and graduate level. Exactly the kind of thing engineering students do for degree credit. I would specifically exclude any work that involved design of even the smallest part of a competitor's vehicle. We are just talking of research to characterize real world crash event conditions, the response of vehicle structures and safety systems to those events and explore tools for analysis of the crash behavior of vehicles and their components. You guys who know kids in school studying mechanical engineering or work with young engineers who may still be going to night school for a graduate degree or finishing up and undergraduate degree program see who you can interest in this. Do you have an engineer or scientist friend helping with your race effort who works in the analytical side of the business and has knowledge of the subject of dynamics or mechanical vibrations and maybe computer resources at hand? How about someone with an FEA resource that can model the strength and deflection or either 2d or 3d structures? Maybe there is someone out there who can move this forward.
Ed Weldon
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Two things Ed.
One that's not my quote, not sure how it got mixed up....
Two, I agree with your concept and would never stop anyone from building a LSR vehicle the way you discribe. However your last paragraph would most likely make it nearly impossible for a home grown racer to ever finish their project as the lack of people willing to help or as I'm sure others have found from time to time the engineer tends to never finish the side projects as other more interesting or profitable items come his way. (Yes I understand this would be for school credit.)
Not to mention, racing as a hole is usually more involved from an engineering standpoint than most young engineers grasp at first. Yes, they can do it, but when?
The rules the SCTA puts forth are not as arbitrary as many would have you believe.
