F/C chassis integrity (1 Viewer)

[Randy]

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Maybe Bob Meyer, our resident chassis fabricator can weigh in on this one.

Interesting you should ask Randy. SFI and NHRA have stated my thoughts and experience, along with Don Long and Dave Uyehara (total of 120+ years) have been invalidated. I guess I have nothing to contribute.
I no longer wish to be involved in "the heat treat issue".

Bob

Maybe your thoughts, along with Don Long, Dave Uyehara and Johnson's were just validated.

RG

 

[Darryl]

Maybe your thoughts, along with Don Long, Dave Uyehara and Johnson's were just validated.

RG

There's certainly something to THAT statement Randy! In all my years of watching Funny Cars travel down range I've not seen a chassis pull apart quite like that. Also, I've always heard about the breakaway parts of a Top Fuel chassis but I've also NEVER heard of that being applied to a Funny Car. I've always heard the driver was considered 'safer' between the two large tires and that they acted as a 'shock absorber' type of deal.

God bless all the Force's and their teams right now, and let's hope we hear nothing but good things on John's recovery.

 

[Nick Name]

"Way back in the day" when we were running front motor top fuel, the idea was, in the event of a serious crash, the motor was supposed to come out of the car and hopfully go some where away from the rest of the car. The driver was presumed to be pretty safe sitting down between the rear tires.

Jay

 

[MM]

top fuels used to have motors in front lol

but yes the idea is for the motor chassis to break at the motorplate and in front of the motor so that in the event there is an engine fire they driver isn't sprayed with oil, fuel, fire or pelted with shrapnel from the motor coming apart

 

[Butch]

Yes funny cars are designed to "break" just ahead of the motor plate at the "step down". Please read the SFI spec if you doubt that and you'll see why/how. The idea being it would let the motor "get-a-way" in case of a bad crash. For some reason it broke else where something I am sure SFI, NHRA and JFR to name but a few will be looking into.

However instead of everyone second guessing what happened and "playing" chassis builder. Has anyone thought of calling Murf and saying THANK YOU for building a car that would let the driver survive? Granted JFR had input into how the car was built as all crew chiefs have their own ideas. But it was Murf and his "guys" that built the car - without them being as good as they are John would be laying some where else tonight.

To Murf and the gang THANK YOU for being as good as you are!

For without John drag racing at times would be boring to say the least.

 

[MM]

like i said in the thread about the crash....nobody builds a better car than Murf so you know something had to go seriously wronf

 

[RAPID]

Interesting you should ask Randy. SFI and NHRA have stated my thoughts and experience, along with Don Long and Dave Uyehara (total of 120+ years) have been invalidated. I guess I have nothing to contribute.
I no longer wish to be involved in "the heat treat issue".

Bob

Anybody who wouldn't listen to those 3-has NO BUSINESS with anything to do with chassis safety and design!!!!!!!!!

Rapid

 

[Al smith]

Whos idea was the re-heat treat?

It was my understanding that 4130 chromoly tubing was already normalized from the mill. How many decades has this tubing met military and aircraft standards? Who's idea was it to fix what was not broken? And if there is a joint cluster problem with heat affected areas would it be feasible to use lower frame rails and main hoops that are two layers sleeved of .058 wall tubing for a total wall thickness approaching .120 wall?

 

[unclebob]

Re: Whos idea was the re-heat treat?

It was my understanding that 4130 chromoly tubing was already normalized from the mill. How many decades has this tubing met military and aircraft standards? Who's idea was it to fix what was not broken? And if there is a joint cluster problem with heat affected areas would it be feasible to use lower frame rails and main hoops that are two layers sleeved of .058 wall tubing for a total wall thickness approaching .120 wall?

Al; be careful, with that kind of thinking, there might still be one of those "your vote is invalidated" letters coming to you!

 

[hellfirejim]

I don't have the experience of some of the greats but I was a crew chief on a funny for about 7 years. I have never seen or heard of a chassis coming apart where this one did. And one last time PLEASE, they are not designed to break apart. The motor can come out because it is usually held in place with bolts and aluminum plates.

Stop and think about the stress that a chassis goes through. First you have the torque of the motor trying to twist the chassis. Then you have the torques at the rear trying to turn the rear end at the hit of the throttle. You have harmonic vibrations all the way through the quarter. You have down force being applied to the chassis through the body working against the torque of the motor trying to lift up the chassis. Oh yeah don't forget the negative Gs when the chutes hit.

The very fact that we have not seen this till now says that we can thank our lucky stars that there are really good chassis guys out there. Will The Eric Medlin Project and Ford and all the rest of the people figure out what happened??? I believe so. Perhaps they can develope a testing ptogtam to spot trouble before it begins. Give then some time to work their magic.

Just one man's opinion.
jim

 

[headporter]

What about a Coupler failure. or a reverser failure.. If the reverser broke apart and blew out the side of the case it could break the frame. If the Coupler broke it would break right under the driver. Who knows what would happen after that. What I can see in the video is some thing under the body flying around and the body coming apart. Which would be either body attachment tubing. Hence Carbon fibre peices cutting a tire. After the fact of the front half making a right turn into Kennys lane. Clearly the streering wheel and frame peices are rolling to a stop.

As far as making a Funny car able to break apart like TF's do. In Front of the Driver... Well I doubt ANY driver would get in one. At least no one who wanted to keep real body parts.

All the Mods Team Force did to Fix the drivers Head problems Stayed in Tack the parts that broke looks to me like the the Engine to Drivers cage rails.

If as you Mistakenly think the Chutes Pulled apart the frame.. Then why would this not happen WAY more often when every one Yanks the chutes. The chutes were not even Out and the front part of the car was all ready in front of KB.

What I find not so Unusual is people saying way to much about tires. Yes they were Chunking and even one driver in his interview said wow your tire is chunked.

Ok so here is a Thought Process for you all to think about....................

Tire Shake + more Tire Shake + More Tire shake = Broke or Cracked FRAME.... If not weakend and oh whats was this Talk about Bumpy tracks..

What I would do if I was in the Position to see whats going on in these cars LONG ago. Is put strain gauges in these cars at various points and a few other Measurement Devices to find out how Much and where in the frames things move. If these cars are flexing way more then they think. I would think it's a good reason to load and unload the rear tires. Due to the Spring back.

I don't know if John was in a Flex Tube Chassis But I would be willing to bet. NHRA and SFI needs to see if things need to be PARKED. If they in fact are flexing to a point of weaking the related tubes under DEcompression then well I guess more brain power needs to be used.

Oh and Were is the Xray machines for older frames. I wonder if one of these would have saved Darrel G. from getting hurt long ago.

Get well soon John I will see you at the Track.

 

[Just Paul]

If as you Mistakenly think the Chutes Pulled apart the frame.. Then why would this not happen WAY more often when every one Yanks the chutes. The chutes were not even Out and the front part of the car was all ready in front of KB. .

Say what?

As far as the chutes pulling the car apart, It's obvious something is very wrong with the car by the way it looks. The chutes were not the cause of the frame being broken, but in a way did pull the back of the car with John in it away from the rest of the car becasue the chutes were only slowing that small section. They are clearly open in this first pic.

This second shot tells me the chassis is already in 2 pieces, the chutes are out, and the rear spoiler/deck lid is facing us instead of being parallel with the ground. This rear body work stayed with John the rest of the way.

 

[megadeth]

Maybe they should start doing an eddy current test of the chassis after a certain # of runs.
If there are hair line cracks that are not visible to the eye a eddy current test would definitely help.

 

[Randy]

The very fact that we have not seen this till now says that we can thank our lucky stars that there are really good chassis guys out there. Will The Eric Medlin Project and Ford and all the rest of the people figure out what happened??? I believe so. Perhaps they can develope a testing ptogtam to spot trouble before it begins. Give then some time to work their magic.

Just one man's opinion.
jim

You have "not seen this until now" because you have not *heard* of it until now. This is not the second chassis to come apart. Do you think they are going to post all their problems on Nitromater? You will never hear a driver in an interview say "We broke the engine and dropped the crank on that run and by the way every weld on the frame broke, too." You think I'm joking?

Chassis builders were thrown under the bus expressing their opinions about the issues that led up to this. One of them is ready to disconnect his phone because his "worthless opinion" is now more valuable than a spot in the final countdown to the championship. Under his greying hair is all the math, geometry and calculations that have provided safe chassis for many years to the top racers. His cars have crashed hard without a failure, yet they chose to ignore this guy who will give you an engineering lesson so over your head you'll struggle to comprehend any of it no matter who you are. Anyone who knows him knows who I'm talking about.

In 28 years no one was killed in a FC. Last weekend we almost had two in less than 6 months. Thank GOD it didn't happen. So what has changed? In the last 28 years we have seen the most violent FC wrecks that resulted in relatively minor injuries. Now cars are falling apart without hitting anything. That is a fact. The chutes deploying just disconnected what was already broken. That is a fact.

Pardon me for being totally blunt, but the problem is: Those who thought themselves wise, although having good intentions, have shown themselves to be foolish. Those who thought they know the most have been shown to know the least. Tough decisions have already been made and the scramble is on. The original horse wasn't broken, and for some reason someone screwed up trying to fix it.

If they outlawed funny cars you'd never see me at the track again. Knee jerk reactions to something that wasn't broken in the first place is something we don't need. Like I said, I have a horse in this parade, too. Someone screwed up trying to fix what wasn't broken in the first place. 28 years and no fatalities. Suddenly all this. And decisions made by the rule makers will effect me and everyone else with a FC. I have a good ol' Uyehara chassis/Plueger clone and I'd rather crash in that at 300 miles per hour than take a chance on anything new being considered or mandated by the looks of things. I hope they consider what the establishment has to say about any rules changes (ie, my favorite German).

I'm outta hear because I'm getting myself all fired up and I know too much about all this. No reason to spill any more beans.

Adios,

RG

 

[DCM]

put strain gauges in these cars at various points and a few other Measurement Devices to find out how Much and where in the frames things move.

That is the only way to KNOW what the stresses and deflections are. It will require work to make this type of system work with all of the electrical noise, etc. of the engine, but I'm sure it can be done.

In fact doesn't JFR have a 7post [I thought I read that somewhere previously]? If so, that would make this a routine task for anybody well versed in instrumentation/strain gauge technologies.

I also agree that the chutes may have resulted in final separation of the parts of the car [because the rear was decelerating and the front was not], but no way that the chutes caused the chassis to fail.

 

[Keith Burgan]

I just got offf the phone with someone who is very close to this deal and the following is the best info that I can provide on various aspect of this situation.
The funny car frames from McKinney do use heat treated tubing AT THE RECOMMENDATION OF THE TUBING MANUFACTURER. As I have stated many times before the currently supplied tubing varies in tensile strength from batch to batch and lately has tended to be at the low end of the spec. The mill (Plymouth Tubing) can supply tubing with a tighter tolerance re tensile strength but the minumum run is 5000 feet in each size so for practical reasons the tubing goes through a tightly controlled post manufacture modification process to get it to the recommended numbers.
The Force incident was the result of the failure of the left tire and the resulting harmonics are what broke the frame. Basically the frame is held rigidly at the mid plate and at the rear end with the roll cage and seat tubes also supporting the rails and effectively boxing the chassis at their attachment points. When the car began to shake following the tire failure the high amplitude oscillations simply sheared the tubes off at one end of the cockpit area.
Initial analysis has indicated that even if the main rails were as thick as .120 wall at that point they still would have sheared. The frame was not pulled apart by the chutes, they simply slowed down the rear section of the chassis after the rails broke. Force's car did have the "prop" tube under the front of the main hoop as he had requested that the front hoop be moved forward on the upper rail and in doing so it did not meet the minumum 1" set back from the support sleeve inside that rail.
Once again this has nothing to do with heat treated tubing, weld quality or anything else that is easy to fix. The problem lies with the harmonics when a tire fails and causes the car to oscillate violently.
Just my own personal opinion but could the revised tire design that followed the previous incidents have changed the way the tire reacts when it chunks or delaminates?

Roo

 

[Toejam]

Amazing, everyone had thought(?) that FC chassis were far safer than TF Chassis after all those TF Chassis Failures we've seen in recent years. That still may be the case, but I've seen far more violent tire Failures on FC's in the past that didn't cause a Chassis failure!

 

[TR]

There sure is a lot of knowledge out there. Reading it all especially from Randy sure makes you wonder, but also makes you feel like there is a lot of people out there that put a lot of thinking into the fatigue factor that these chassis have to take. Thanks to everyone, and bottom line thank God John is alive.

 

[Smiley]

I
Once again this has nothing to do with heat treated tubing, weld quality or anything else that is easy to fix. The problem lies with the harmonics when a tire fails and causes the car to oscillate violently.
Roo

I may be off base here, but wouldn't the heat treat process make the metal more brittle as well as stronger? Would a non heat treated tube have more of a tendancy to flex and bend instead of fail completely?

 

[hellfirejim]

Randy,
I know you are up on the tire about this but what I said was about the chassis coming apart. You can't be racing these for very long and not know that they crack welds and break bars. I have seen that for years. What I DID say was I had never seen one come completely apart........

The most reasonable explaination I have heard and read was that it was harmonics the broke the chassis. Just like any metal if you bend it continously it will break.

I would think that the combination of rule changes may have changed the playing field as far as harmonics and how it affects the chassis. This would include tires and chassis.

jim