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The vehicle weight is a bit disappointing. The engine power is about what I expected, but for $400k+ I thought the dry weight would be more like the actual weight. And it's interesting that they compare it against the McLaren 650S LT and Ferrari 458 Speciale. Both cars that are a fair amount less expensive (and in the Ferrari's case, obsolete by 2 years).
Man you're obnoxious. Although I admit the Harry Carey meme was pretty funny.
Your blowing up and ensuing dissertation over an insignificant comment demonstrates that you can't have a calm, mature conversation and debate. I admit I mis-read your parenthesis but I hardly "corrected" you, let a lone in a condescending manner that would warrant your response. I clarified the bulkhead design but the addition of "not the aluminum extrusions" spun you off into this crazy rant to the extent as if I called your baby ugly.
You could have easily replied with saying that you never said the forces went though the extrusions, I would have agreed and apologized, and we could have moved on... If you don't have a problem being wrong, you sure have an anger issue and thus I don't really care to continue a conversation with you. However I will end my end of this discussion with this post.
Yes I am very familiar with the NSX's history and its chassis. Iv'e cut them apart, and have seen cars with the front and rear frame rails cut off and other cars literally cut in half to see the cross section of the main frame rails.
We once again circle back to the main issue of semantics. The definition of "Monocoque", "Unibody", "Unit Body", "Space Frame", etc... are not isolated as there is a lot of crossover, contradictions, and ambiguity in these definitions. The aircraft definition of "Monocoque" is that the object has 'structural skin', in which the chassis is integral with the body.
Since the NSX has no body panels that are structural and they all bolt on, it's not a true 'monocoque' despite Honda officially referring to the the NSX's chassis as an "Aluminum Monocoque". Heck, the McLaren MP4 F1 car was the first carbon fiber 'monocoque' car, yet all of the exterior body panels bolted to that carbon 'monocoque', so technically it doesn't fit the true definition either. The Lotus 25 F1 car had a true aluminum "monocoque" chassis in which the exterior body skin was the structural chassis, as are most modern F1 and prototypes (but carbon).
"Unibody / Unit Body" cars follow the Monocoque definition of "structural skin" and thus, multiple body panels (typically the rear quarter panels, upper trunk area, A-B-C-D pillars, roof, side sills etc...) are a structural part of the chassis. Most cars these days are unibodies (Porsche 911, Mustang, CTS, Camaro):
997:
Mustang:
CTS:
Camaro:
Now refer back to the previous images of"space frame" chassis' where there is no structural skin since all of the body panels of the Audi R8, S8, Lotus, and SLS bolt on to the chassis. Henry Ford had a patent in the early 40's for a plastic bodied car with a space frame chassis in which the "frame structure which will resist all normally encountered stresses independently of the body panels". -The NSX follows this definition, which was my argument.
The NSX is in fact a "combo job" and uses innovative aluminum extrusions for its frame rails, which Honda calls a "honeycomb frame", as well as complex aluminum stampings to connect these extrusions, and stamped aluminum body panels. No matter how you look at it, the NSX's chassis is a hybrid and does not fit one definition to the T. But then again the construction of most production cars don't fit perfectly in to any of the definitions, so you can argue over semantics all day long (like the differences between "Twin Turbo" vs "Bi-Turbo") but am not willing to.
You asked for an Aluminum space frame car that weighted less than 3,000lbs. I provided the NSX-R which is a hybrid of space frame construction and does not fit 'unibody' by not having any structural body panels. The conversation did not need to go this far.
/
The convo DID need to go this far. I think a lot of us were both entertained and educated...all at the same time
It's been a while since I posted here. The back and forth between Bill and Mr EG was one of the more technically entertaining posts I've read in a long time
I can't remember who was arguing what but I will agree (with whomever said it) that most cars are a clear hybrid between the pure form of any structural type. I doubt there has been a structurally "true" body on frame car for MANY decades (perhaps since before WW2). To the best of my knowledge the term monocque came from the racing world. I would argue that in general the early monoque cars generally didn't meet the aviation definition of the word since most of the structural chassis was still covered with bodywork. This is very true when you look at sports racers. Consider this Porsche 962 chassis and a tube frame sports racer chassis.
Race cars went from tubes to aluminum panel construction using methods based on those in the aircraft industry. Thus I suspect they adopted the aviation name for such stressed panel construction even though the stressed panels weren't exterior panels.
Consider the "space frame". A true space frame is one which uses only elements in tension or compression. The joints could be modeled as ball joints. None of the strength is due to the bending stiffness of a member or joint. The closest things I can think of to a true space frame is a TV antenna tower. Even some of the best tube frame racecars I've seen aren't true spaceframes. This 917 replica is probably as close as any:
I think unibody, the term the US car companies used to describe cars that weren't body on frame, weren't so much meant to describe the chassis (though it was part of it) as the way the car was assembled. The idea of putting the powertrain and suspension together into a subassembly then attaching that to a body subassembly results in a different type of assembly process vs one where these parts are bolted into a chassis. Of course as I say that, the Corvette and BMW both assemble largely completed (though not self supporting) powertrain-suspension subassemblies into a body/chassis subassembly.
Not a very good picture but here is a BMW chassis being mated to the suspension and powertrain. The suspension and powertrain are being held as an assembly by a large jig.
And the same for the Corvette
OK, I've blathered about this enough Love the new GT and the old one as well.
I think Billy said it, but it was a strawman (unintentionally as it likely was). I never suggested that modern cars can all be neatly categorized by their chassis type, with no overlap. On the contrary, on most exotic cars these days, it's fairly common for them to have a chassis that takes from a little of column A and column B as well.
Man, looking back over this thread reminded of what a hissy fit Billy threw. It was incredibly frustrating discussing this topic with him because continually kept arguing against points I didn't make. I particularly liked the part where he claimed I was being condescending when the entire basis of his original commentary was to try to be condescending. I have a lot of respect for Billy's racing accomplishments (I've been a fan boy since he was racing in Time Attack) and his technical knowledge. However, his approach to having a discussion is very frustrating. With how offended he got at a little ribbing --and, to be candid, I responded to his basically being a jerk by poking fun rather than by indulging my MO of being a jerk back-- and he responded like the boy whose mother had always told him he was the most handsome kid in school. I don't think Billy's a fool. Far from it. I think he knows his stuff. I just don't think anything shown in this thread is indicative of what I have come to expect from him.
In any event, Billy's ultimate point that the NSX was a space frame vehicle and not a unibody is wrong for a couple of reasons. The most painfully obvious evidence I can point to is basically everything Honda has ever said about the car. They consider the original NSX to be a unibody. Full stop. In fact, they pat themselves on the back pretty hard because of this, and rightly so. As I pointed out earlier, the whole novelty of the NSX's chassis was that they were able to make an aluminum unibody. I'll come back to this in a second.
Billy specifically references (Mustang, Porsche 911, Camaro, etc.). First, come on. No one in this thread needs him to explain what a freaking unibody car is. Second, he unknowingly undermines one of his earlier points. Billy points to the fact that the rear quarter panels on the NSX are removable, therefore it has no stressed outer skin, ergo it's not a unibody and must be a space frame. Yet he posts a picture of a 997 Cup Car. Said 997 Porsche is undoubtedly a unibody car, and Billy obviously agrees. Building on what they learned with the 997 GT3 RSR, when Porsche developed their 991 RSR, they made the rear quarter panel a bolt-on affair. Doing so does not make the 991 RSR a space frame chassis vehicle. It is still a unibody. That's just the thing, practically all unibody cars have their rear quarter panels affixed with just a few welds. The Fontana Nissan time attack 350 that Billy raced against back in the day wasn't a space frame car by virtue of the fact that they "unwelded" the factory rear quarter panels and installed aftermarket (custom) widebody composite rear quarter panels. Heck, one can very easily remove the rear quarter panels on the MR2 Spyder, and it's not a space frame car. The point is, that the NSX's rear quarter panels are unboltable doesn't make it a space frame vehicle. I really feel that Billy is clinging to the original meaning of unibody within an aircraft context in order to make his point, but whatever could be said about an NSX that would make it NOT a unibody when compared to the way Billy's using the term, could be said about any other production car that anyone can plainly see IS a unibody car.
What then does make something a unibody car? I would argue that it has to do with the production method, at least in as far as the novelty of unibody production methods dictate and account for the way loads flow through the chassis. Unibody cars differ from space frames (and other chassis types) in that they are made from hundreds of mass produced sheet metal stampings. Whether we're talking about a 911 or a Honda Accord, their chassis are essentially jigsaw puzzles made of many rather flimsy pieces of steel (or in the case of the NSX, aluminum). These pieces are positioned by robots and spot welded, with a few key welds being handled by hand. Further --and this is important-- these vehicles all make use of folds and creases and bead rolls, all in the name of turning flimsy thin metal into a structurally sound component. This may seem insignificant, but this hints at the defining characteristic of a unibody chassis. Thin metal only gains rigidity by manipulating it into a shape that is structurally advantageous. My Corvette, for example, has floor panels made of basla wood and some composite material. Most importantly, they're flat with nary a structural thought put into them. But why? Because the floor panels of my Corvette are not inherently tied into the structure of the vehicle in terms of loads being fed through them. The floor panels of the NSX (or any other unibody car) are bead rolled, creased, folded, etc. This subtle difference says it all. In the original airplane meaning of the word unibody, the vehicles in question were hollow and all loads were fed into the outer skin, and all portions of the outer skin were effectively stressed under load, no different than a soda can. The skin WAS the chassis. But unibody cars have never had their outer body panels fully stressed. The term unibody has never, in the context of cars, been used to mean the same thing as it's used when referencing airplanes. No, the key characteristic of a unibody chassis is that all of the stuff beneath the skin is stressed as a solid entity in the same manner that a unibody airplane's skin handled the loads. And, again, it's all made of a jigsaw puzzle of individual metal pieces that are attached to form an overall structure. Other production methods and chassis types rely on the inherent strength of their material thickness and only feed loads along structural paths made of thick material, while superficial components are used for things like plugging the gaping holes left between the tubes. Not so with unibody vehicles.
In other words, what makes a unibody a unibody is that, unlike the floor panels of my Corvette which are just there to keep me from seeing the ground and are merely along for the ride, even the floor panels in a unibody chassis are stressed, so the structure pressed into them has to reflect this. This is why all portions of a unibody chassis are bead rolled, folded, etc. If the robots on the assembly line screwed up and installed non-beadrolled, etc. floor panels in your Honda Accord, the chassis would be compromised, in part. If you were to install sheet metal beadrolled floor panels in my Corvette, it would make no difference. Well, guess what. When you look at an NSX chassis, it is immediately apparent that all of the panels and junctions where one would find such manipulation of flmsy metal in order to give rise to a structural component in any given unibody car, you have precisely that in the NSX.
If one wanted to make a tube frame car by using unibody techniques (i.e., stamping metal and spot welding) you would not be able to accomplish anything like what you would accomplish with a tube frame chassis. Sure, some piece of machinery could take thin steel and roll it into something resembling a tube and a robot could cut, weld, and position these "tubes" into something that looks like a tube frame car. But it wouldn't work. The inherent properties of a tube frame car center on how loads are fed through the various nodes, how triangulation is used to create sheer planes, and how the wall thickness of the tubes handle the loads. In other words, making thin-walled sheet metal into something resembling a tube frame car wouldn't accomplish the goal. The materials and methods used are not incidental to the chassis type. The NSX relies (or at least primarily relies) on all of the gimmicks that a unibody car uses to turn flimsy thin sheet metal into a series of structural components. Further, it makes use of long, continuous panels that handle loads and it ties everything together not at single point nodes but along much less defined paths consisting of a multitude of junctions at the many interfaces where spot welds and seam welds tie everything together. This is what makes it a unibody chassis.
Now, as I've already suggested, if Billy is of the position that the NSX chassis is some sort of hybrid due to the extrusions used in the main box of the base of the chassis, I won't put up much of a fight on that. Again, I am of the opinion that there's something of a ven diagram in effect with respect to practically all exotics. But to unilaterally declare that the NSX has a space frame chassis is not accurate. At best it's a unibody with an asterisk.
Hear me out on this. I would argue that both the 962 chassis and the tube frame chassis below it are both monocoque chassis. However, I would not say that they are both space frames. The tube frame chassis feeds loads along paths that join at fairly obvious nodes. On the contrary, while the 962 chassis clearly has some junctions wherein they would like the majority of the loads to be fed, they way the many pieces are riveted together forms multiple points of interaction and feeds the loads along the "skin" of the various pieces. In short, the "walls" of that house are stressed like a shed you buy from Home Depot whose walls are the structure. Conversely, the tube frame car is a space frame, I would argue, because it is more like a brick house; the 2x4 structure takes the loads and the vinyl siding is serves a different role (if you can pardon the crude analogy).
For these same reasons, a unibody car can be a monocoque but not a space frame. Okay, tell me how wrong I am. Haha.
01-26-2017, 07:52 AM
