The (one and only) '0846' Debate Thread

Rebuttal??? We haven't being shown the "dispositive" Ferrari documents that we are told already exist. The "rebuttal" you speak of could also take "several months."

 

I would like to hear solofasts opinion or others on it. Point is, calling it fact before anyone weighs in does not lead to a real conclusion.

 

Can you point to one instance where you have done this?

 

Are you not one of the people that was from the David doesn't have to say anything camp?

 

Agree and surely Ferrari spoke to DP.

Pete

 

My point was that Tony had effectively corroborated Nathan's explanation from years ago.

 

Vincent,

Stop typing mate. Why are you making this personal instead of focusing on the car? Return to your family and get some real quality time.

If we ever do statistics on the posts of this thread we will discover that too many by you and others are just trying to provoke an argument.

This thread has been going for 12 years, people DO change their mind. I have. Used to feel strongly that Jim's car was based on the remains of #0846, but now ...
Pete

 

Wow, with this long a post I barely know where to start...

First of all, once you get back behind the cockpit this isn't a semi-monocoque structure anymore, it's a tube frame with the engine acting a central beam. Very different and in this case they didn't bend any of the monocoque, it's much too stiff for that. You need to analyze the back half of the car as a truss structure and look at the resulting loads accordingly.

The impact sustained in the incident at the Targa was were the car basically slid into the curb, essentially sideways the best you can tell. There is no other visible damage to the car other than to the suspension and wheels.

Here is a link to an instagram photo of the car following this incident...

https://www.instagram.com/p/BAFxs6kkBzy/

Now if you look at the damage there is apparent deformation to the rear suspension, that is the wheel spindle isn't square with the chassis anymore. To get this kind of damage you had to smack the curb really hard, and Nino was essentially sideways when he did it. You can't see the front wheel in this shot but in the photo in Jim's pdf, the front wheel isn't damaged visibly, but the front tire is flat, but the wheel isn't missing any pieces (which it would if a real magnesium wheel would have hit very hard like the back wheel did). From those photos you can assume that when Nino lost it he hit the curb with the rear wheel first and took the brunt of the impact. So much for the bit about the arrow and wall...

That and given the rear weight bias of these cars the majority of the lateral loading from this kind of incident would clearly be input to the chassis through the rear suspension. Since the lower control arms are short it takes a huge load to buckle them. Consequently most of the load went into the rear subframe that carries the rear suspension.

These loads were high enough to damage the rear suspension, but not before they transmitted a very large lateral load to the rear subframe.

You're assuming that the engine stiffens the frame and that is true for torsional input, but in this case most of the loading was lateral (some obvious torsion, but most of the reaction was lateral since the impact was at the bottom of the wheel and not at the tire contact patch, the lower the load input the higher the torsional content). In this case if you hit the wheel you're putting the lateral load almost directly into the right rear lower control arm, and very little load is input into the upper control arm. Yes it's below the CG, but the input is mostly lateral load to the chassis at the lower rear suspension mount point.

Torsional loads in the rear of this chassis go through the engine to the rear bulkhead, and are reacted in the bulkhead, as you've noted, but lateral loads from the rear suspension go through the long tubes that go from the outer end of the side pods to the rear subframe. If you look at the bulkhead you'll see that there is no stiffness out of plane and therefore the engine really doesn't participate in transferring lateral loads from the rear suspension to the mid section of the chassis. I'm simplifying a bit, but if you view the chassis from above and input a big lateral force on the RR corner of the subframe you'll see that force is primarily reacted by the two long tubes that go forward from the rear suspension to the outer sides of the car. You can do a free body diagram of it, but since the bulkhead doesn't have out of plane stiffness, it isn't going to react the lateral load at the rear subframe. The engine forms a beam along with the tubes along side it that stiffens the system and makes sure that it all moves as one piece, but the only thing keeping that beam of the engine and transmission from swinging (in the plan view) are those angled tubes. Since they are the stiff element resisting that motion that is where all the load goes.

This is where you'll see damage from this kind of incident. Since the tubes are long and bucking is function of a square of the tube length, the tube in compression on the side opposite the impact would be the first to fail and it would bend in the middle of the tube. And it doesn't take much force to do that, if you failed the rear suspension you could easily buckle that tube. Since the rest of the frame is soft in that direction, it flexes and there is no damage, after the impact it comes back to where it was, more or less.. If you look at the amount of motion that it takes to buckle that long tube in compression you'll be amazed how little it takes. The forces are pretty small. For a 36 inch long tube of 1" od and .062 wall it only takes 4466 pounds of compressive load to buckle it. This is certainly higher since there is other structure, and there are two of these tubes (one in compression and the other in tension), but the bottom line is that it's easy to see how the impact with a curb would result in damage that wasn't related to the structure near the engine.

So to sum it up, the torsional stiffness of the chassis really isn't what's trying to resist the failure and the stiffness of the engine really doesn't enter into it. The engine prevents the tubes along side it from bucking, but really, once the engine is installed those tubes don't do much anyway. There's a good bit of redundant structure in there, mostly to support the engine when the transmission isn't in the car and it isn't attached to the rear subframe.

The good news is that once you jack the car back to straight and fix whatever damage was done to the long tubes, the car was fine, and that is why it was quickly repaired and went to Le Mans.

 

Steve, in Vincent's defense, my theory does not actually prove anything, but rather offers a realistic solution to the PDF's explanation of chassis damage. The only conclusive "Proof" would be to either do a complete CAD engineering package for the car, including structural design, engineering, and metallurgy; and then simulate a crash using finite analysis software, or simply crash one of the others to see what would happen. Of course, the second option is ridiculous, but these two options are the only way to definitively Prove the Point.

I have run enough finite analysis of structures to know that my theory, while not definitive proof, is certainly right on the money, and certainly more credible than the theory that a left side chassis tube would receive torsional deflection damage from the very light right side accident that damaged both rims and some suspension pieces. Look at those pictures of 0846 at the Targa. Did that minor bender really destroy the left side of the chassis? Or even the right side?

But I honestly do not think the point even needs to be proven. The chassis pictures confirm that the two chassis in debate are clearly different. If we had photos that matched 0003 and 0846, then this point might have some value, as we could look for forensic evidence to link the detail-matching chassis with the damage.

But trying to link damage to a chassis that is clearly different, is like performing an autopsy on a 50 year male to try to prove a theory about an adolescent female. I just do not see where any correlation lies. (Sorry for the morbid comparison)

 

Anyone have any information besides the post by Wax claiming that the car is being reviewed at Ferrari? Physically at Ferrari and preferably with the Classiche group would be the point.

So far it has been crickets to this question.

 

Solofast, I appreciate your post and the position that you support. I agree with your analysis of the structure. I simply do not agree with the amount of load required to compromise the structure. As I look at the pictures of the car at the accident site, I am looking for details that might indicate what could transfer the load you speak of to create enough load to pass through the stressed structure aft of the bulkhead.

If you state that the car hit rear first, then the arrow explanation still applies. It just bent from the other end.

If you look at the structure that immediately transferred the loads to the chassis, you see we are initially dealing with a tire. A tire is soft, with an enormous amount of compliance, and therefore, ability to absorb vast amounts of energy. We then have a rim, which will allow a great deal of deflection, and energy absorption, which is displayed in the damage in the image. Next, we have suspension members, such as the upright castings, which look like they too, absorbed their fair share of the load. I can not state if they cracked or fractured, and they may have passed on more energy if they did not fail. As you state, the lower Suspension arm would have the greatest ability to transfer a load, however, it is insulated by the components I have mentioned. The damaged and repositioned wheel shows evidence that the energy was successfully absorbed, and I believe, therefore insulated from the chassis.

If we take the aggregate of the components that absorbed energy, and look at the visible damage, it is a hard stretch for me to believe that there was enough energy left over to create the type of damage as explained to the left side of the car.

Having not seen the pictures of the visible damage, I would concur with your position 100%, as what you state is correct for a major impact, but the kinetics just do not support the position for me.

Just imagine that somebody came over and kicked the tire. It would certainly not bend the chassis. How about if you hit it with a mallet?

While I am not ascertaining that the loads sustained in this accident were as light as a tire kick, I will maintain the position that the accident damage presented would not twist a semi-monocoque, or beam chassis at the location suggested. If at all the car would start to deform forward of the bulkhead.

With respect,

Anthony

 

Vincent - if nothing else (other than correcting using my location as your location which is frankly a bit pathetic) can you please spell Ing Forghieri's name properly. It is Forghieri, not Forghiari or even foghari. Pleased show him some respect.

 

Point taken. However, a balance of probabilities would weigh to your theory being very likely and the damaged tube on the left hand side would not result from the TF 67 crash's relatively minor impact on the RH wheels.

 

Again, you have to start thinking and analyzing this as a truss structure and look at what elements are reacting the lateral loads. It's not even close to a semi-monocoque. If you're thinking of this as anything else you're assuming lateral strength that just isn't there. What this structure really is is a heavy beam down the middle that is hinged at bulkhead, and the only thing keeping this beam from swinging from side to side are those two small tubes. It's stiff in both torsion (due to the engine contribution and the way the engine is connected to the bulkhead) and it's stiff laterally because these tubes are locating the massive beam from side to side, but when it comes to bucking the structure can't take much load before it fails. Not an issue if you don't hit something and fine for a race car and it works, it's just not very robust.

As I understand it, the only damage to the left side of the car was one tube (the tube mentioned above) that had some buckling damage from this incident. The car was quickly repaired and was none the worse for wear. Supposedly the tube damage was repaired by cutting the tube and inserting a plug into the tube and welding it all back up. This kind of thing is commonplace on space frame race cars that have an incident. Any chassis tweaking or resultant deformation is small, is taken out by re-aligning the car and resetting the corner weights, and Jim claims his frame has some deformation that is also consistent with this kind of thing. Also the uprights and wheels on these cars were real magnesium. Immensely strong for their weight, but no energy absorption since they are relatively brittle. The rim didn't hit the curb first, but with only about an inch of sidewall it obviously hit hard enough to fail the suspension. I've seen and repaired bent space frames and the kind of damage that they are saying that 0846 had is consistent with what I've seen when tube frame SR car hit a tire wall and those things are notoriously soft. Admittedly there was body damage too, but unless as others have suggested someone did an FEA model of this you wouldn't know for sure.. Or, if you had some closer dimensions of the car and frame you could do a quick back of the envelope calculation and estimate the G loading it took to buckle that tube and you wouldn't be far off..

But if you go back and look at that tube and calculate the deflection that it takes to create that bucking load, it's very small. That 36 inch tube can only take about .030 inches of pure compression before it buckles, and all of that lateral load is going into those two tubes. one in tension and the other in compression. Moreover the stress at the time of bucking is only 23kis, or about one fourth of yield. The right side tube would never even stretch before the left side tube buckles. If the tube is welded and there is some bending present at the same time (as there is in this case) then the loads to create buckling are even smaller. Space frames are wonderful things, but if you load them more than they can take they fold up pretty quickly as this calculation shows.

While it's perfectly fine for as much load as you can get out on the track, it just doesn't take kindly to any abuse. As noted above the tube would FAIL in bucking at a stress level of only 23ksi. That is about 1/4 of the yield strength of chrome moly tubing, so as you might expect it would never break or crack in normal use, because you're only putting maybe 10ksi in compression or tension depending on which way you're cornering. It would just buckle if it got overloaded. This is also why you don't generally see very long space frame tubes. These two diagonal tubes are a bit of an anomaly. I don't think I've seen a space frame tube this long in any other chassis that I've can recall. Most tubes this long have some kind of support to preclude bucking, or they're larger diameter. As others have noted these cars would fold up in a real accident and seriously hurt you and this is why.

Run some numbers and you'll likely find it only takes a few "g's" of lateral load all put into the rear wheel to cause that tube to fail.

 

Just so that everyone can see the alleged repaired tube as a result of the TF67 accident.
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Solofast,

I enjoyed your position on the accident damage, and again, I concur with everything you have explained about the chassis, with the exception of the amount of load the chassis experienced from the crash. If the car would have been traveling faster, or hit the curb with a more excessive vector, then I would agree with seeing damage to the left side of the chassis. Although you recognize the fact that the chassis tube would buckle under compression, I feel like you might be overlooking the damage to the engine mounts. The engine, which you correctly state as the beam section, would indeed impart a sheering force to all of the side mounts, as the width of the engine creates a very wide radius of gyration.

Again, what I disagree with, is that the the chassis could not have sustained enough load from the accident at the Targa. As I am sure you know, the accident site at Collesano was an extremely slow corner. If you look at the corner, you will see several factors that disprove the theory that 0846 sustained severe lateral loads from its contact with the curb.

I have included images of the accident site, and also an image of a diorama. I apologize, as the diorama is clearly unscientific, however, it lends a good overall view of the accident site that can be better verified with accurate photos that show clearer detail of the actual scene. I do not own any of these photos, and I apologize in advance for utilizing images without permission.

In the many images of the corner, and of the car, you will see several clues.

First of all, it is an extremely slow corner that by virtue, does not allow a great deal of speed, or kinetic energy required to impart the damage on the chassis that you specify. If you look at the rear 3/4 image of 0846, you will see a debris stream under the right rear wheel. I believe this was either caused by the immediate impact that might have been captured, or as the car is proceeding after the contact. In either case, evidence of the cars position is clearly shown in relation to the corner by examining the fisheye lens image of the same corner. In both images, you will notice the concrete structure that links the location in both photos.

If the impact happened before the concrete structure, which approximately divides the corner in half, the impact would have taken place earlier in the corner, where the angle of the curb is considerably smaller than the optimal trajectory of the car. I belive that in this case, the damage to the car would either be excessive to the right front corner, or the car would have jumped the curb. I do not believe the car could have turned sideways and struck the curb with enough lateral force in any location before the apex of the corner.

Instead, I believe that he had negotiated the corner, but drifted outside as he accelerated through the apex, contacting the rims on the curb.

Additionally, I believe the image of the side of the car at rest that shows it off at a slightly better angle shows that both wheels hit the curb, as well as a slight indentation in the lower bodywork just ahead of the front wheel. It also shows that the rims deformed and broke out about 100 degrees on the front wheel, and about 210 degrees on the rear wheel. This tells me that the car had forward momentum in order to "roll" the rim over the curb, rather than slide sideways into the curb. As you correctly stated, true magnesium wheels are brittle, and I think the damage looks consistent with a light contact between a slower turning wheel with a high curb. If the car would have slid into the curb with great lateral force, the rims would have certainly shattered, possibly even at the hub.

Last, If you look at both the diorama and the historical photos, you can see that the angle, point of contact, and the roll out after the contact are within a very short distance, which supports low,kinetic energy. The car has also not departed the course, which would be consistent with a slower speed incident. But most importantly, the evidence of the car after contact simply does not offer any substantial conclusion to support that the chassis buckled under the loads suggested in this slow, confined corner at the Targa. Consequently, I can not accept that the car struck the curb with enough lateral load to deform the far side chassis tube.

With regards
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Notice the wall on the right hand side of the photo. This is the location of 0846 as seen with the debris coming out from under the right rear wheel
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Notice the damage to both rims, and the small dent just in front of the front wheel, low down on the body work.
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This is a good overall shot of the corner that offers a perspective of the attainable corner speeds. I understand it to be a first gear corner
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A non scientific diorama that offers a laymans overview of the incident
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Whatever the outcome of the engineering discussions, my god those photo's are cool and a reminder to all just how freakin brave those drivers were to do the race at speed in cars like that with no track safety at all. Reminds me of a video of Vic Eflord at speed in the Alfa 33 which was inspiring. Thanks for posting.

 

lunch-with-david-piper | Motor Sport Magazine

Mike Parkes left Ferrari in 1971
0003 was built in 1974 according to the written statement of Piper and was A CAR (not a chassis) but was it?
0900 was built in? 1971? under the watchfull eye of Mike Parkes or also in 1974 (when Parkes already worked for Fiat/Lancia)?
If yes 1974 and 0900 was built by Manicardi e Mesuri why not built 0003 frame at same chassismaker? (it is cheaper making 4 frames then let someone else to start all over from scratch and make new suspension pick up point moulds)
0900 (DP02), 0900a, 0900b and 0003 (strange number is it?)
DP02? what is DP01....
First outing 0900: 1982? Was it finished after 0003?

IMHO this is all not logical.

 

Anthony,

By Nino's own admission he got in too deep and hit the wall on the outside, he was waving to a friend and missed the braking point, so he was going a lot faster than he should have been at corner entry.... He wasn't accelerating out and if you look at the photo you posted and then the next photo it is clear he hit the wall on the outside at mid-corner. The photo at the time of impact shows he was totally sideways with very little forward motion. Basically he slid into the curb and while he wasn't moving very fast at all, almost all of the energy of the impact went through the rear wheel, which is why the suspension is bent, either the hub destroyed or the lower control arm collapsed, or some combination of both.

What it more likely is that he knew he was in trouble and "pitched" the car to try to make the corner.. The car hit going sideways the rear end first..

Also look at the height of the curb. It's taller than the tire. The tire didn't take up any of the impact, it was essentially all wheel.

This wasn't a "glancing blow" to the curb on corner exit. This was a sideways slide into a curb with the back right side hitting squarely with the car sideways. No surprise that it took out the RR suspension and easily could have done the minor damage to the chassis.

 

Collesano 2005.
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Excellent photos. All is still there... Same stones. Bad day for Nino.
Photos Eric della Faille - © Stanford University Libraries.
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