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Hello- > What does an unstressed body panel mean? Is that where it doesn't form part > of the structure of the car? A good analogy is to look at biology - endoskeleton vs. exoskeleton. Endoskeleton is like human beings - our main structure (bones) is seperate from our outer covering (skin). Exoskeleton is like insects - their main structure IS their outer covering. It would be incorrect to say that our skin is _entirely_ unstressed, but it's really the bones that do the huge majority of the job. When you think of a stressed-skin vehicle (car, airplane, etc.), think exoskeleton. Just like in nature, they can be simpler and lighter, but are fairly limited as far as design goes. When you think of an unstressed skin, think endoskeleton. Again just like nature, they are more complicated and heavier, but allow much greater flexibility in design. Which is better? Well, it all depends on what you want to do, how much money you have for design and engineering, and how much money you have for manufacturing. It's an open-ended problem with no "correct" solution... ah, design is fun! :-) Our little VWs are stressed-skin vehicles. That's one reason why they're simple, light, and cheap. However, they are (admittingly) also quite limited... they aren't that stiff and there's no easy way to add stiffness without changing the entire design. Most modern production cars have an unstressed skin, which is one reason why the bodies crumple up so much easier in collisions yet the passengers have a greater chance of living. Without dramatically increasing cost, they offer more rigidity and more flexibility for design changes, at the cost of having more parts and weighing a little more. Many race cars also have an unstressed skin. When your manufacturing quantity is one, it's a hell of a lot easier to design a tube frame or equivalent that does the job well, then place a lightweight skin on the top of it. The results aren't bad at all. To make a rigid, lightweight, stressed-skin race car is a daunting engineering task. It takes budgets like F1 to make it possible. And, if they want to make any changes to the car, the whole thing has to go out the window. Considering that Schumacher makes over $80 million a year, it's possible to understand that this probably isn't a big deal for them :-). Take care, Shad Laws LN Engineering - Aircooled Precision Performance http://www.lnengineering.com ------------------------------------------------------------------- List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org