Dragster chassis technology...ignored??? (2 Viewers)

[scotty]

The first appears to be not welding heat treated tubing to untreated. Is the section of the chassis that is mandated to be heat treated fabricated from heat treated tubing, or is it fabicated from 4130 and then treated as a unit?
Somone may be able to answer this question. From what I know of heat treating, the correct solution would be to fabricate the chassis and then heat treat the entire unit. Of course, since there is no data, no one knows how an entire heat treated chassis would perform. For the last time, NHRA needs to hire a qualified engineer before a driver dies.

Great point Jim. To answer your first question, the tubing is heat treated before chassis construction. And you are correct, ideally the chassis would be heat treated AFTER construction and even then, not really heat treated to increase strength. Only to normalize the stresses of construction (read welding). However, what might come out of the 'oven' is a warped chassis as the members release to where they want to go from the treatment. What this would show you is the final state the chassis is trying to get to.

As to the point of increasing strength by heat treating, remember you can't get something for nothing...this is a universal LAW. If you increase strength of a material without adding material you have to sacrifice something somewhere...maybe life cycles?

 

[stanman]

Scott,

Dead on with a zero! When NHRA implemented the rule requiring heat treated 4130 tubing for the area of the chassis directly behind the cockpit I took a lot of flack for calling the change a load of B.S.. Guess, I feel a little bit of vindication after reading Biller Miller's letter on DRO.

I'm no credentialed expert... but one of my opinions from studying chassis design is that the idea of introducing a more rigid material (heat treated tubing) to try and work with less rigid material into a fixture (the chassis) is just asking for stress points. Rather than allowing the chassis to flex over the entire length, the heat treated material creates a rigid section into the chassis. The loading of the chassis has not changed so the force that would have been spread over the entire length of the frame rails is now going be concentrated over the lengths of the frame rail outside the more rigid heat treated section... thus increasing the stress on the normalized sections of 4130 tubing.

Furthermore, my opinion was that the only plausible solution was to require heavier walled tubing. But lord knows the racers didn't want to make their cars heavier.

 

[Ponyhntr]

Because of their lawyers the NHRA and GoodYear can't talk about tires because of the Russell lawsuit that's still ongoing.

It has been settled, so that can't be an excuse anymore.

http://www.nitromater.com/nhra/10686-russell-v-goodyear-settled.html

 

[turbo ken]

It has been settled, so that can't be an excuse anymore.

http://www.nitromater.com/nhra/10686-russell-v-goodyear-settled.html

That's why I said that, while the lawsuit was going on the nhra and goodyear lawyers would not let them talk about tire failures, now that the lawsuit is over, they can design and build a new fuel tire.
It's all about the lawyers!

 

[Jeff]

Well I guess we can scratch the Russell lawsuit as ongoing . . . maybe we'll learn more now.

 

[Tom]

The issues concerning failures on the TF and FC cars has been interesting reading. It appears that everything concerning the failures to this point has been reactive. The teams and manufactures are throwing more changes in the design of the chassis to correct the problem. Think of it as a tuning issue on one of your cars. Throwing a bunch of changes to a motor and clutch without knowing what corrected the problem could only confuse the issue. Small changes along with a history of those changes helps you get to your goal. I think we have over looked one possibility that might be a cheaper and more proactive method of finding the failures before they occur. The question is: Are the teams inspecting the chassis on the TF and FC cars on a regular basis?? If so, what method of inspection is performed? A visual is not enough. They should be performing an eddy current or similar inspection process for subsurface cracks. This inspection could be performed in 30 to 45 minutes. The equipment and standards are not that expensive and the training usually comes with the purchase. The teams could perform the inspection during the servicing before the next race. Air Carriers have been doing this for years. If cracks are discovered in specific areas and reported to the manufactures, then this allows the manufactures the opportunity to improve their product.

This is just my opinion, you know what 's worth!!!

 

[Bob]

To tell you the truth I was sitting here in front of my computer eating Cheet-oh's and got bored so I made it up.

Walk in to anyone's pit this weekend and ask them who did it.

Now if I could just get all this orange slime off the keyboard.

It's over at DRO and it's being reported as Bill Miller. I'd say Miller is about as much an authority on fuel racing tech as there is.

edit, here's the link: ::: Drag Racing Online ::: Columns - Agent 1320 - 10/4/2007

Thanks Brent. Makes for interesting reading.