Interesting article

[enjenjo]

This is an article on funny car chassis that raises some concerns  http://competitionplus.com/index.php?option=com_content&task=view&id=4358&Itemid=24

Interesting read, which raises some questions.

[chimp koose]

very interesting indeed. Sometimes NHRA seems to put politics into the rulebook. A good example is the PSI screw supercharger in the 80's. it was deemed unsafe due to blower failures involving rotor explosions. The real story as reported by SS/DI magazine at the time was a fear by rootes blower manufacturers of being put out of business by the much more efficient screw supercharger design.

[Uncle Bob]

Fascinating stuff!  It could be that NHRA is playing politics, but what about the political view the writer interjects?  

There were three things I kept expecting to see addressed as I read, but they never were.  First, why would McKinney be so committed to heat treated as opposed to normalized?  Is it that he feels it gives him some advantage in chassis dynamics that leads to better E.T.?  Or does he think it's safer?  I seriously doubt it's a financial consideration, especially when we're mostly talking about one of the best financed teams out there.  What would be the results of a McKinney design using normalized rather than heat treated tubing?  In an otherwise seemingly thorough article those questions are never addressed.  Did McKinney tell this guy to pack sand at some time and now there's a vendetta in process?

Second, the auther went into the welding effects on titanium body support structure, but never addressed the same issue as relates to the heat treated tubing in the chassis.  Is that why McKinney does the repairs himself?  Since nearly all the discussion is about chassis it seems an odd ommission.

Third, somewhat related to the second and ignoring the vailed, unsupported  references to top fuel, if McKinney supplies more than half the funny car field, why was there only one other specific non JFR example?  Could it be that JFR has a problem caused by something they do in their build-up, they way they do welding (if they do), or who knows what?  Obviously they wouldn't do something harmful to themselves on purpose, but something seems to point more specifically to them than others.  Maybe it's just the high profile nature of John and the team, but again, it's possibly a factor that remained unaddressed.  

Failure analysis isn't always a 1,2,3 deal, and dueling "expert" opinion is nothing new.  It took the death of Earnhardt to give NASCAR a real boot in the safety behind, let's hope NHRA and the teams in drag racing don't need as big a beating to get their attention.

[unklian]

There were several other NASCAR drivers killed,
before head office woke up.

Kenny Irwin,Adam Petty,Clifford Allison,and a few more.

SFI needs to be doing cycle testing on chassis designs and materials.
Specs should be written by unbiased professionals.

Force and Coil should know better.

Time for ALL these guys to wake up.  

[Charlie Chops 1940]

I worked in the camshaft business part of my career as a materials manager. We bought cast iron, nodular iron, forged steel and billet steel material...flame hardened, induction hardened, furnace heat treated, pit heat treated, and on and on. I had a metallurgist on staff and access to a few more. All I can say is that it must be black magic because I could never get more than one of them in a room and have a consensus of opinion.

I gave up, they are some of the squirmiest professionals I ever dealt with. The people who have to actually make parts tend to pick the guy they think is right and move on.

That article is living proof and another agenda to say the least.

Charlie

[kb426]

I have a span of around 20 years in my dragster building career. In that time I repaired more cars than I built from scratch. 4130 N tubing is all I ever used. The life span of that material is very short due to fatigue and work hardening so I really am surprised that anybody would use a material with what would appear as a shorter life span still. I'm glad that I'm not the builder of the cars in question. I never had anyone get hurt in any of the cars that I built. That fact is something that I'm very pleased in knowing. Those of you that are old enough to remember Lee Shepard being killed at Ardmore may remember the chassis discussions that followed. I was one of those that called the NHRA tech department and asked for a chassis change to mandate a funny car style cage in that class. It took forever before that came about. I sent a letter to NASCAR requesting the same changes and never even got a reply. My exp. has been that sanctioning bodies are very slow to change. The PSI blower was one exception. I was somewhat involved with the car that led to that ruling. That blower had just been in Norm's shop about 2 weeks before that incident. While it was true that the roots people had seen their business really shrink before that, nobody could explain why that blower disintegrated into about a million pieces. That was why it was banned. It almost put Drazy out of business. It took him better than a year before he could prove what happened and why. He designed the testing that was used after that to certify all screw blowers. I was very lucky at that time that I didn't have one on my car. Having that amount of money tied up would have hurt badly. His testing to design the screw blower is what caused the changes to the roots designs. He knew more about the roots blowers than the people making them. NHRA certainly needed to do something because nobody knew what would happen next. But, this was the same organization that took forever to require blower restraints on blown cars. Look how many people were killed by flying blowers before something happened. Their lack of consistency in safety matters back then was disturbing. I don't have any answers about this. I'm glad that I'm not involved anymore. I have limited respect for the way NHRA handled stuff during the 20 years that I raced.

[wayne petty]

seems like the best thing to do is to put the driver in his own cage.. separate from the structure of the car...legs included... use the armor plate over the driver cage instead of filling in the triangular openings in the chassie...


forward thinking saves lives...maybe kb426 could draw up some plans to submit as an idea to the nhra or force racing..


wayne

[unklian]

How long until they figure out those extra braces don't solve the problem ?

[jaybee]

As an occasional follower of drag racing a couple of questions come to my mind.  First, is the chassis builder getting something in the behavior of that chassis that makes the car faster, and they're willing to rationalize away compromising the safety to make that happen?  Second, if it's correct that the chassis failures are being caused by tire failures instead of the other way around, why is it acceptable to build a chassis such that a tire failure tears the chassis to bits?

[msuguydon]

I posted a few week back asking about tires, bias vs. radials, unknowingly walking into a very contentious debate.

Frank you just did the same.

This is a HUGE issue in the drag racing world right now.  I do not pretend to understand all the issues but if you want to dive head first into this fist fight, head to the Nitromater web site.... this is the HAMB board of drag racing... many of the chassis builders, team owners, drivers and crew members are on this board.

http://www.nitromater.com/nhra/

I will add a tad of fuel to the fire.


For many years in my professional life I have been involved in new product development, either as a team leader or as a team member in a variety of capacities.  Most of this was for consumer products, sporting goods, furniture and some automotive.  When we were introducing a new product all of our vendors had to provide testing and certifications for the material, processes and manufacturing techniques they intended to use..  These certs had to come from certified test labs, we did microscopic tests, FEA, FEMA, burn testing, tensile, shear, fatigue blah, blah, blah testing...

I happen to have a buddy that builds front end dragster chassis as well as mounts Funny Car bodies to the chassis for several of the pro NHRA teams, including Dale Greasy and John Force, to name names.

He has shared with me that it has only been in the last few months that the tube builders are starting to do basic material cert work, FEA etc.. I was shocked!!!  With the money these guys have, attention to detail and potential threat of killing drivers, it just floored me they are not doing basic, simple, incoming material specification testing.

My take is that you have two or three frame/chassis builders they have a ton of experience and seat of the pants knowledge, the tire manufacturers and the engine folks (well funded and with lots of engi-nerds and puters) are making quantum leap performance strides and this "cottage industry" that builds frames is being left in the rear view mirror.  Add another gusset.

I will share a real life example, I was involved with a project in which the company I worked for was supplying a metal shaft with a plastic gear mounted on the shaft, it was a speedometer pinion gear for a military vehicle.   We had to supply certifications on the metal shaft prior to forming, post forming, pre heat treating, post heat treating, including microscopic analysis of the carbon penetration of the heat treat.  That was for a * speedo gear...


These chassis builders don't know what kind of tube they are getting, variability within a lot of tube they buy, not tracking lots, not checking random pieces within a lot of supplied tube, no traceability..

I think its time to step up the professionalism.

That is all that I have to say on that...  

[msuguydon]

http://www.nitromater.com/nhra/10854-prominant-fc-chassis-builder-speaks-his-mind.html

[Dave]

I posted a few week back asking about tires, bias vs. radials, unknowingly walking into a very contentious debate.

Frank you just did the same.

This is a HUGE issue in the drag racing world right now.  I do not pretend to understand all the issues but if you want to dive head first into this fist fight, head to the Nitromater web site.... this is the HAMB board of drag racing... many of the chassis builders, team owners, drivers and crew members are on this board.

http://www.nitromater.com/nhra/

I will add a tad of fuel to the fire.


For many years in my professional life I have been involved in new product development, either as a team leader or as a team member in a variety of capacities.  Most of this was for consumer products, sporting goods, furniture and some automotive.  When we were introducing a new product all of our vendors had to provide testing and certifications for the material, processes and manufacturing techniques they intended to use..  These certs had to come from certified test labs, we did microscopic tests, FEA, FEMA, burn testing, tensile, shear, fatigue blah, blah, blah testing...

I happen to have a buddy that builds front end dragster chassis as well as mounts Funny Car bodies to the chassis for several of the pro NHRA teams, including Dale Greasy and John Force, to name names.

He has shared with me that it has only been in the last few months that the tube builders are starting to do basic material cert work, FEA etc.. I was shocked!!!  With the money these guys have, attention to detail and potential threat of killing drivers, it just floored me they are not doing basic, simple, incoming material specification testing.

My take is that you have two or three frame/chassis builders they have a ton of experience and seat of the pants knowledge, the tire manufacturers and the engine folks (well funded and with lots of engi-nerds and puters) are making quantum leap performance strides and this "cottage industry" that builds frames is being left in the rear view mirror.  Add another gusset.

I will share a real life example, I was involved with a project in which the company I worked for was supplying a metal shaft with a plastic gear mounted on the shaft, it was a speedometer pinion gear for a military vehicle.   We had to supply certifications on the metal shaft prior to forming, post forming, pre heat treating, post heat treating, including microscopic analysis of the carbon penetration of the heat treat.  That was for a * speedo gear...


These chassis builders don't know what kind of tube they are getting, variability within a lot of tube they buy, not tracking lots, not checking random pieces within a lot of supplied tube, no traceability..

I think its time to step up the professionalism.

That is all that I have to say on that...  

   
Just kidding buddy.. I have to go read the stuff been busy  real busy and aint had time yet.. Maybe if you get a second cause i really havent read all this post either you could tell me.. does this involve stress relieving the chassis also.. Ive seen this debate come up a lot lately and I myself (and im no metalurgist) think it cant hurt.. I have a bit of experience in heat treating steel but most of it is in rf heat treating or as the big guys call it induction hardening.. I guess it cant hurt to know a bit about it but now days i tend to shy away from if simply because the machine we use to do it requires a very hi voltage (vacuum tube machine) and after being on the other side it kinda bothers me to play with it   . I dont really find it hard to believe there is a shall we say blind area when it comes to chassis and metals.. Hey drivers wanna go fast and they can be the worst offenders and till you really get messed up like force its easy to ignore stuff that should be taken seriously..
Wehn i get time ill follow this further..
Dave

[msuguydon]

   

Well I am no race car builder... that's for sure and well documented on this board  :oops:

The question my friend is this simple and this hard.... To flex or not to flex?, that is the question.

[slocrow]

Gee, interesting.................flexing is the least of the problems for the drivers, as I think it's their life here and it's ultimately a team problem. No, laying this on NHRA as that safety dog won't fly. If they say that a seat belt is mandatory it's because they want to keep the flow moving not prolong your life. To assume other, like they are interested in your (drivers) safety is naivety as it's finest. And, as a team, to abdicate responsibility of that safety is a ......................no, no.
Sure a sharp lawyer might argue that they, the NHRA, took on the safety responsibility when they wrote rule one and are liable. Even if the NHRA is sued and loses aren't we ultimately responsible for our own safety. It's a risk to race.
It's a choice to run on the thin edge and sacrifice some safety for the benefit of speeds & times. If it helps to run less weight for example, for this should we risk life & limb? It's a team choice to be "competitive".
I might suggest that it's the team manager or sponsor or the owner that is responsible for the final construction and it's safety verification. After all it's their property that's presented, safe, as they presumably wouldn't knowingly forgo safety for fame, would they? There's no large monetary gain for them, is there?
No, it's not the NHRA's responsibility for our safety, it's ours and in the risk we're willing to take.
Whether it's chassis, tires or team, it's really the teams chore to resolve. Nobody needs more rules.....................
Anyway, that's what I was thinking while having a pop or two...................Frank

[enjenjo]

I knew there would be some controversy, that's why I posted it.

The question my friend is this simple and this hard.... To flex or not to flex?, that is the question.

There is always more than one way to do things. You can build rigid, or  build flexible. Either one will work. Bit if you build rigid, and it flexes, it breaks. If you build flexible, and it doesn't flex, it breaks.So adding a tube, or gusset may be the worst thing they could do, depending on the design.

As an example my car trailer has very little resistance to twisting, torsional rigidity, I built it that way on purpose. It flexes a lot when towing it empty. But when loaded, there is very little flex. The load stabilizes it. After 20 plus yours on the road, and more miles than I like to think, there is not one crack in it. now if I was to stiffen up one part of the trailer, and let the rest flex, it would concentrate the forces in one place, causing it to crack.

For the same reason, most highway bridges are designed to flex, we normally don't notice it because we are moving, but if you stand on a bridge with traffic traveling over it, the flexing is very noticeable.

My take on the funny car chassis, is they are designed to flex. Adding tubes of gussets, with move the stresses to areas that weren't designed for it, causing failure. by the same token, using heat treated tubing cuts down on the flexing allowed before catastrophic failure.

Another thing I have noticed, most of these failures happen on deceleration. when you are slowing down, all the loadings are turned on their heads, and a frame designed to control the acceleration loads, are working against design to slow down.

I don't pretend to have the answers, I am just pointing out that there is more to this than first meets the eye.