F/C chassis integrity (2 Viewers)

[You!]

Something just dawned on me...was there an ESPN camera on board in John's car? I sure hope so because alot could be learned from that footage.

The only thing I'll say or add here is that some may be under estimating the vibration and violence that occurs when ANY tire (even at 65 mph!) comes apart.

 

[Keith Burgan]

Randy,
interesting reading but the key words here are "I am by no means an expert in this field of metallurgy or structures, but as one can see by searching around and finding the correct information and presenting it in proper form, the reason for using 4130N becomes clear."
Once again the assumption is that the 4130 is being modified to an excessively hard condition and that is not the case. As I stated in an earlier post the manufacturer (Plymouth) recommended the current proceedure. I think that they may know a little more about their product than someone posting on Wikipedia. I do not see any listing of Joe LaCour's credentials or bona-fides in the posting. Is he a qualified engineer with race car experience or is he another link posting Franklin Ratliff?

Joe also states "Many have commented on the past and recent catastrophic failures of Top Fuel Dragsters as if the "tremendous loads" were to blame. Also mentioned was that the chassis is "designed to break apart in a crash". This of course is all non-sense. The loads on a Top Fuel Dragster chassis, while higher than an average race car, are by no means tremendous. And in a crash, containment is always preferred to non-containment."

If Joe does not know that it is a proven fact that jettisoning portions of the structure to reduce the mass in an impact situation helps preserve the vital driver protection area he once again puts his credibility in doubt.
I would also question his definition of an average race car and its comparison to a fuel dragster. When a T/F car achieves around 5 g's at the launch it is surely under a lot more stress than a super comp car at say 2 g's. The mass of the T/F car is also considerably greater so the peak loadings are higher for that reason as well, and that is before we factor in the torque loading on the chassis.
The quality of Mr LaCour's dissertation can probably be gauged from his stress/strain graph which has no units specified for either scale.Nor does it spell out to what level the heat treated sample is modified.

The info on the Lincoln Electric site is backed by a well known and respected company while two other links on the subject of welding and associated proceedures are to a commercial site trying to push a specific product. No necessarily a bad thing but once again the "expert testimony" is not backed up with any references to the credentials of the person providing the information.
I could probably dig out my old engineering study materials or Google up some references to post much the same info as Mr LaCour but that does not make me a credible expert on the subject and I would not profess to be such.

Roo

 

[Randy]

Roo:

You should call him up and ask him if he is Franklin. He would love to talk to you. His contact information is on his web site on purpose. Let me know what he says. His site was refered to me by someone deeply involved in all this who also happens to be an engineer involved in metals. For obvious reasons, his name is being witheld.

I have yet to find anything that states the opposite is true. I have, however, seen the results that confirm it. If you have any reliable sites or information I could read that disputes or parallels these claims I'd certainly like to read it or them.

I have had an open mind on this. The more I learn, the more I'm learning how much I really don't know. You mentioned a grocery list of chassis builders in a previous post. Would you like to tell us what they think about this. I can. I would ask you this, do you actually have an open mind? Don't you for one second think all this could be true? What part of "normal" is multiple self destructing chassis? Before this year I couldn't think of any.

Not to bore you to tears, but I was 1/2 owner of a dragster that was totally destroyed in a top end crash at Bakersfield back in 1989. The cause of the crash? The chassis builder used cast jig plate aluminum on each side of the rear end to mount it to the frame. The plate looked like torn Wonder Bread. Being suspicious I confirmed it. The brake lines did a better job trying to keep the rear end in the car than the plates did. The chassis builder saw it and never acknowledged what he did or why he did it. One of his worker bees said it was made from some scrap they had under the bench and they didn't know exactly where it came from. It was not a whole lot of fun watching my friend Greg Oliver get cut out of our brand new (9 runs) dragster. They landed the Life Flight helicopter on the track and flew him to the hospital where he made a full recovery once his skull fracture and broken wrist healed. The car was junk.

Now I question everything especially when I see something that stinks. If a tire vibration blows a frame apart that easily (less than one second) then we might as well pack it up.

I think I've about heard from everyone on this deal. I mean everyone. Somehow I've been appointed the official whipping boy backed by some big cheer leaders who must remain anonymous. I'll take my licks because I have many friends in this sport who earn a living sitting in these things every other week. Except that I am dimensionally challenged I'd still be sitting in mine.

I understand a hired metalurgist may have recently confirmed much of what has been said. You might check it out.

RG

 

[none]

Roo:
call him up and ask him someone deeply involved in all this
an engineer involved in metals information I could read
Would you like to tell us what they think about this. I can.
The chassis builder The chassis builder One of his worker bees they didn't know exactly where it came from
I think I've about heard from everyone
big cheer leaders who must remain anonymous.
I have many friends in this sport who earn a living sitting in these things every other week
I understand a hired metalurgist may have recently confirmed much of what has been said. You might check it out.

RG

Your thoughts are completely lost (to me at least) in your many non-specific sources and references..................

 

[Keith Burgan]

Randy,
I am trying to keep an open mind on this subject and I am not trying to beat up on you but there has been so much crap put up by people who don't have the inkling of a clue about most of what is going on. I stand by my comments re Mr LaCour's Wikipedia entry for the reasons stated in my previous post.
I have been building race cars for 40 years and am paranoid about someone getting hurt because of something that i have done (or not done). That is why all of my stuff is put together with NAS bolts and jet nuts (not the "Grade 8" stuff touted by Spitzer, Damron, etc) and is generally over-engineered. I have no desire to build fuel funny cars (or T/F dragsters) because I think that the whole deal has gone beyond the capabilities of a shop such as mine. The basic mechanics of building the car are simple but the engineering side of things is getting too complex.
I will try to talk to John Medlen in the next few days and get his take on all this as he is the one who has been most affected by it.

Roo

 

[Randy]

Your thoughts are completely lost (to me at least) in your many non-specific sources and references..................

Nothing personal, Mel. Unfortunately they will stay that way (anonymous). I haven't mentioned many names except naming the people I have replied to and maybe one or two others if necessary. That's the risk of getting involved. Lurkers become voyuers and want all the dirt. This isn't about dirt, it's about getting the wheels back on the horse so it can race again without hurting anyone. Want to see who they are? Turn on the TV. The people who need to know, know who I am talking about. No name dropping.

 

[Randy]

Randy,
I am trying to keep an open mind on this subject and I am not trying to beat up on you but there has been so much crap put up by people who don't have the inkling of a clue about most of what is going on. I stand by my comments re Mr LaCour's Wikipedia entry for the reasons stated in my previous post.
I have been building race cars for 40 years and am paranoid about someone getting hurt because of something that i have done (or not done). That is why all of my stuff is put together with NAS bolts and jet nuts (not the "Grade 8" stuff touted by Spitzer, Damron, etc) and is generally over-engineered. I have no desire to build fuel funny cars (or T/F dragsters) because I think that the whole deal has gone beyond the capabilities of a shop such as mine. The basic mechanics of building the car are simple but the engineering side of things is getting too complex.
I will try to talk to John Medlen in the next few days and get his take on all this as he is the one who has been most affected by it.

Roo

I'll send you a PM.

Say Hi to your neighbor JB for me if you see him. Tell him I might need some more side windows and a windshield for the Monte Carlo body.

RG

 

[The Counterfeiter]

I had lunch Monday with a guy who has a huge amount of experience on race car and aircraft metallurgy. Crew chief for Mickey Thompson and other car owners for ten years at the Indy 500 and experience at Reno air races and land speed records at Bonneville. His opinion was that welding heat treated tubing to untreated tubing is a recipe for failure.
We don't know if part of John's chassis was heat treated and if so, where it was joined to an untreated section. A reliable souce told me tonight that this was not a slip tube chassis (which probably would not affect this failure) and that slicks were compromised by fractured tubing. If you take a close look at video from the finals show, it appears that the slicks were punctured, but not delaminated. So . . . are Ashley and Robert at risk if their chassis are the same as John's? A lot of issues here, we can only hope that JFR make it safely to the end of the season.

 

[rosco]

I know that Don Prudhomme sent a Top Fuel Chassis to Panoz in Georgia, he was looking into the possibility of placing the driver in a capsule like cockpit, much like an Indy car, after seeing what happened last Sunday, maybe someone will develope this type of car in the future,


Torco Racing Fuel's Competition Plus.com - Drag Racing's Internet Magazine - FORCE DEEMS "PROTECTIVE TUB" NEXT PRJECT

 

[Iron Mike]

I have noticed when welding chrome moly tubing on race cars the last 10 years or so, that some of the tubing has impurities in it. It sparkles some when you weld it. I noticed this change when tubing may have started coming from china. You can look at the tubing and see the difference in it. Anybody else ever noticed this?

Mike

 

["Dr. Dirt"]

Hey Mikey!
Shouldn't you be in bed by now? Don't be such a stranger here!

 

[Keith Burgan]

I have noticed when welding chrome moly tubing on race cars the last 10 years or so, that some of the tubing has impurities in it. It sparkles some when you weld it. I noticed this change when tubing may have started coming from china. You can look at the tubing and see the difference in it. Anybody else ever noticed this?

Mike

Mike,
the purity of the tubing is definitely not at the levels that were in place when I first came to the US in the late 80's. It appears that the current stuff is at the low end of the spec in that regard and it is not just the Chinese material.

Roo

 

[BlueStangGT]

I know nearly zilch about this subject but I just wanted to make a quick comment to the primary participants in this thread that are not only familiar with the structures and their composition but indeed are professionals in the field.

I have found this entire conversation positively fascinating and eye-opening to say the least. Thanks for sharing your views, knowledge, and expertise on this matter so that some us can come to a greater understanding of the principles at work. I think this has been one of the all-time best threads this board has ever spawned, at least in the 4 or so years I've been participating. Please keep it up.

 

[Jay]

So guys let me just ask you stright up is heat treating fuel cars safe and good for our sport? Thanks in advance

 

[Keith Burgan]

I had lunch Monday with a guy who has a huge amount of experience on race car and aircraft metallurgy. Crew chief for Mickey Thompson and other car owners for ten years at the Indy 500 and experience at Reno air races and land speed records at Bonneville. His opinion was that welding heat treated tubing to untreated tubing is a recipe for failure.
We don't know if part of John's chassis was heat treated and if so, where it was joined to an untreated section. A reliable souce told me tonight that this was not a slip tube chassis (which probably would not affect this failure) and that slicks were compromised by fractured tubing. If you take a close look at video from the finals show, it appears that the slicks were punctured, but not delaminated. So . . . are Ashley and Robert at risk if their chassis are the same as John's? A lot of issues here, we can only hope that JFR make it safely to the end of the season.

Jim,
the left slick on Force's car chunked and set up a vibration/oscillation that fractured the frame. There was no debris from Bernstein's or or parts falling off John's car contributing to the failure. It was the same type of harmonic that Eric Medlen's car went through but this time they had the "black box" recorder to better analyse what happened.

NOW!!!! READ MY LIPS. The tubing was not heat treated to the point of being brittle. The process is a slight modification of the 4130N specification and is performed mainly to tighten up the variation between batches of tubing with the added benefit of adding a little strength. The variaton between various batches of tubing as supplied by the manufacturers is greater than the increase that results from the heat treating.
FEA analysis of the Force deal indicates that the frame would have failed with regular 4130N, mild steel or even if the tubes were .120 wall (more than double the actual thickness). The FEA analysis included the use of the vibration module which is the key to this whole deal--the car shook apart.
All of the "reliable sources" are talking out of their arses if they have not been closely involved with the whole deal. I checked the link that Randy Goodwin posted last night and even called the guy involved as have John Medlen, Jim Head, Rob Flynn and several others. He is not a race car engineer and admits that. I am afraid that I was not impressed with his grasp of race car dynamics as is quite often the case when "civil" engineers get involved in this sport.
I don't profess to be qualified either but I have been around this sport for over 40 years and have seen the non race car qualified engineers come and go but the basic designs never change. The builders like Hadman, Plueger, McKinney, Long, etc know what works from being intensely involved for a long time but at the current performance and stress levels we are getting into the twilight zone in some areas. Aircraft design reached that plateau a long time ago and it would be incromprehensible to design a plane subject to the kind of loadings that fuel car undergoes without the aid of a computer.

Roo

 

[TR]

I have noticed when welding chrome moly tubing on race cars the last 10 years or so, that some of the tubing has impurities in it. It sparkles some when you weld it. I noticed this change when tubing may have started coming from china. You can look at the tubing and see the difference in it. Anybody else ever noticed this?

Mike

I HAVE NOTICED THE SAME THING MIKE, EVEN CHANGING OUT WHAT I THOUGHT WAS A CONTAMINATED BOTTLE OF ARGON. CLEANING THE CRAP OUT OF THE TUBING DIDN'T HELP. SOME OF THE TUBING IS JUST NOT AS PURE AS IT USED TO BE IT SEEMS LIKE.

RICK

 

[nunya]

Roo, If a chassis has been built a certain way for many years and is still built the same way with the only difference being heat treated tubing and we have 2 catastropic failures in 6 months couldn't this be the problem? BTW I read your lips and I don't think the heat treating makes the tubing brittle I think it is welding it afterwards that does it......as I have been told.

 

[Fuel FC Fan]

New Here.
Couple things, Just wanted to say that I'm happy J.F. is going to be alright after last weekends event. He is truly an amazing person, the guy is seriously hardcore.

Just bought my first Funny Car and hopefully we might get some runs in later this year, (It was easier to buy the car than to try and land a seat) and after reading the great information posted on this thread regarding Chassis integrity I was curious if testing a Fuel Chassis "Foam Filled" would be worth taking a look at???? Would it soothe out some of the Harmonic's in the frame and still allow some flex in the chassis? Has onyone ever gave it a try?

 

[Keith Burgan]

Keith,
the change in the tubing is well within the window of weldability and that is not the problem. In both cases the Force cars went thorugh a period of intense vibration due to tire damage. In most of the prior incidents related to tire failure (Bazemore at E'town for example) the majority of the tire came off the car very quickly and the high frequency vibrations dd not occur.

Roo

 

[hellfirejim]

Keith assuming that what you say is true [and I do agree personally] the question then becomes is it practical and/or possible to build a chassis capable of withstanding this type vibration?????

If taken one step further, if it is NOT practicable what conditions have to change to bring us back to a state where the tires are not coming apart? Is Romine correct in removing down force?

thanks
jim