Medlin explains FC chassis modifications (1 Viewer)

[The Counterfeiter]

Now I'm REALLY confused!
1. All of that additional tubing has now supposedly transferred stress to a point in front of the motor plate. I believe that plate is solidly mounted to the chassis and the clutch can and engine sandwich it with some really stong fasteners. So . . . if the chassis is designed to fail at that point, do the motor and can stay with the driver? Seems contrary to the thought of dissapating energy in a crash by getting the heaviest element of the car away from the driver.
2. How in the hell do you service the clutch? Addtional upper tubes are welded to the chassis over the can. Is the new X member on the bottom of the chassis removeable? If so, red hot clutch parts will have to come out the bottom. Gonna be interesting to see how teams adjust to this between rounds.
Did anyone else see this - any opinions? Jim

 

[Bob]

Now I'm REALLY confused!
1. All of that additional tubing has now supposedly transferred stress to a point in front of the motor plate. I believe that plate is solidly mounted to the chassis and the clutch can and engine sandwich it with some really stong fasteners. So . . . if the chassis is designed to fail at that point, do the motor and can stay with the driver? Seems contrary to the thought of dissapating energy in a crash by getting the heaviest element of the car away from the driver.
2. How in the hell do you service the clutch? Addtional upper tubes are welded to the chassis over the can. Is the new X member on the bottom of the chassis removeable? If so, red hot clutch parts will have to come out the bottom. Gonna be interesting to see how teams adjust to this between rounds.
Did anyone else see this - any opinions? Jim

I haven't seen it Jim but after reading your post my opinion is that these guys are the Pros and they know what they're doing.

You should be able to find more info on the internet.

Look at this Jim. Torco Racing Fuel's Competition Plus.com - Drag Racing's Internet Magazine - JIM HEAD – INNOVATING FUNNY CAR CAPSULE

 

[Al smith]

I haven't seen it Jim but after reading your post my opinion is that these guys are the Pros and they know what they're doing.

You should be able to find more info on the internet.

Look at this Jim. Torco Racing Fuel's Competition Plus.com - Drag Racing's Internet Magazine - JIM HEAD – INNOVATING FUNNY CAR CAPSULE

I found this part interesting

The additions give Head and Davis a more secure feeling with a chassis they both believed was made from “normalized” tubing and later discovered to be heat treated

 

[Bob]

Seems like a strange remark. If you're doing your own chasis mods you should know if it's heat treated. This has been beaten to death but I would purchase say 6061-T0, bend it and then heat treat to say T6. You don't bend T6.

There are only certain alloys that are efficient when welded and I think they are all T0 condition. I would have to look at the specs to be sure. I think any hardened tubing would weaken if welded.

Notice also he spoke about vulnerable areas of the chassis. Why would he wait till now to do something about it?

 

[The Counterfeiter]

Seems like a strange remark. If you're doing your own chasis mods you should know if it's heat treated. This has been beaten to death but I would purchase say 6061-T0, bend it and then heat treat to say T6. You don't bend T6.

There are only certain alloys that are efficient when welded and I think they are all T0 condition. I would have to look at the specs to be sure. I think any hardened tubing would weaken if welded.

Notice also he spoke about vulnerable areas of the chassis. Why would he wait till now to do something about it?

Bob - this EXACTLY what I am talking about! FC teams are trying to apply patches to chassis compromised by NHRA's incredibly stupid heat treating rule. Is more normalized 4130 being welded to the heat treated section?
These people may be Pros, but they have no data (unless NHRA has determined what happened to John's car and is secretly reporting it to the teams). We can only hope that these "fixes" don't reveal the next failure point.

 

[Bob]

Bob - this EXACTLY what I am talking about! FC teams are trying to apply patches to chassis compromised by NHRA's incredibly stupid heat treating rule. Is more normalized 4130 being welded to the heat treated section?
These people may be Pros, but they have no data (unless NHRA has determined what happened to John's car and is secretly reporting it to the teams). We can only hope that these "fixes" don't reveal the next failure point.

I have no idea what NHRA rules are concerning chassis design and the use of heat treated materials. I am 75% sure that any heat treated alloy would have to be heat treated again after welding. Otherwise it will revert to the softened condition or even weaker.

I think they're going to damn fast. There is a limit and I think they have exceeded that limit. I don't think these cars can be made safe.

 

[Bob]

Just found this Jim.

"As with Aluminum, 4130 CroMo has different Temper conditions. However, these temper conditions are not readily identified making the 4130 specification almost meaningless. For example, I may have a bicycle frame advertised as made from 100% 4130 CroMo. The yield and tensile strengths can vary drastically depending if the material was 'normalized' or 'water quenched and tempered'. Although many people think that the difference are conjectural, there is a large variance as the example below depicts:
Temper Tensile strength(PSI) Yield Strength (PSI)
Annealed 80,000 50,000
Normalized 90,000 70,000
WQ&T 128,000 113,000

The temper condition is a post process, meaning that a post-weld, heat treatment is applied. If a CroMo frame is not heat treated after welding, the joints subjected to heat during the welding process are annealed or normalized. Remember that a chain is only as strong as the weakest link. Therefore, if a CroMo frame has not undergone a post heat treating process, the frame is inherently weak. This shortcoming is prevalent in the recumbent industry as most frame builders (who know nothing of metalurgy) ignore this important issue."

Here's the link. Choosing the material

 

[RickyD]

I think they're going to damn fast. There is a limit and I think they have exceeded that limit. I don't think these cars can be made safe.

Actually they have exceeded the limit as long as they have been drag racing. The sport is just an ongoing R&D program. These cars will never be "safe" but they can be made "safer". This will be accomplished through programs like JFRs. His type of research will be what ultimately saves lives and not the kneejerk reactions that have been implemented before without studying the big picture. Unfortunately there is always going to be tragedy as the envelope is pushed. I totally disagree with trying to slow the cars but at the same time I will applaud anybody that will do genuine research in the name of safety. As stated by so many drivers after a tragedy, they know what they may be in for every time they strap in. It is what they love to do. I am envious that I am not one of them.

 

[r2]

Now I'm REALLY confused!

2. How in the hell do you service the clutch? Addtional upper tubes are welded to the chassis over the can. Is the new X member on the bottom of the chassis removeable? If so, red hot clutch parts will have to come out the bottom. Gonna be interesting to see how teams adjust to this between rounds.
Did anyone else see this - any opinions? Jim

Jim-
If you save these pics, and enlarge them even a little- Or put on your other eyes-

You can see that the W or twin V bars or can cage if you will- Is "bolted" on, and easily removed for can/clutch access with minimal effort-

The X brace I don't want to speculate on-

Hope it helps- more questions?? me too!!

Blogs.NHRA.com - NHRA Driver Blogs


iB::Topic::McKinney chassis updates

 

[Rajunz]

The thing that got me when I saw that interview was, John Medlin is standing there with a car that has already been updated with these new safety changes, preparing it for Neff to test on monday, yet Ashley Force couldn't get hers updated in time to make the race???

 

[McGyver]

yet Ashley Force couldn't get hers updated in time to make the race???

Perhaps John does not want Ashley to be on the bleeding edge of technology?
Be real interesting to see how well all of those bolts will line up through the double shear tabs after a few hard runs/tire shake.
I hope it all works out.

 

[Bobby]

everytime I hear they are using 4130 CroMo I think ' why are they using tubing that isn't as advanced as the stuff my bicycle is built from'
Reynolds 853 steel gets stronger when it's welded. Admittedly I don't know anything about drag racing chassis. it's just something I wonder about.

 

[Randy]

Wonder about this...

http://www.nitromater.com/nhra/10801-testing-rumor.html

 

[67 Cuda]

The thing that got me when I saw that interview was, John Medlin is standing there with a car that has already been updated with these new safety changes, preparing it for Neff to test on monday, yet Ashley Force couldn't get hers updated in time to make the race???

I noticed this also but decided to not bring it up. I figure it is best that Ashley is with John right now instead of competing. I am sure the doctors are having enough problems without John being stressed out about Ashley being in a Funny Car this last weekend. This way John will have 2 weeks to get better before he has to worry about her in the car again.

 

[The Counterfeiter]

I started this thread because I believe NHRA has lost control of it's own safety rules, starting with the incredibly stupid heat treating rule. I have a degree in engineering, but it's not in a field that would help here. However, engineers are trained to solve a problem by gathering data and using that data to find a solution. This is not occuring.
If Robert's chassis did fail during testing, it is a result of NHRA allowing team owners and chassis builders to apply fixes that will expose the next failure point. As many others have said, NHRA needs to create a position for a qualified engineer who has absolute control of chassis standards.