JonBoy

To follow up on my prior post about the chassis bracing and diagonal members, see the below photos:

The S2000 has the "X-frame" chassis. Not the front and rear diagonal members along the transmission tunnel to reduce flex. I only have a top shot of it so I can't quite tell what else is welded into the structure (a side shot or a 3/4 shot would help). Also note the major (90 degree) brace running through the middle of the car, right at the mirrors.



The Solstice uses a different chassis design but it does appear to have a similar idea. Note that the front of the transmission tunnel does have some diagonal members supporting it, which would effectively help stiffen the front end. What I can't see, though, is whether the back end has the same thing. If it doesn't, you're still going to see twist back there. They appear to weld in plate behind the seats, which adds a fair bit of rigidity, but it's not going to have quite the same effect (certainly not as efficient - it'll definitely be heavier and it won't do as much to resist twisting).



The Soltice also appears to run a wider main chassis with bracing inside. The S2000 does the opposite and runs a narrower inner chassis with extensions along the doors and such. There are benefits to both designs so I don't think it's worthwhile to say one or the other is particularly better.

JonBoy

[QUOTE=rockville,Dec 13 2006, 11:44 AM]It's not the box of the transmission tunnel that makes it effective, it's that the floor boards and lower panel of the tunnel act like a panel across the bottom of the car.

rockville

JonBoy,
I suspect we are having more of a communication failure than anything else. I am very familiar with chassis loading, structures and the like.

I understand what you are saying. A sheet type panel is only strong in tension, not compression or bending. A beam can have strength in all three. However, it is not the lighter way to do things. In a sense you are comparing a point to point type structure (truss or tube frame) to a structure that carries loads through surfaces (monocoque). It is not a lighter way to make a chassis. In reality most chassis are a mix of both.

Now I don't know much about the boxing on the Kappa chassis. It may have both beam and panel type elements. With out looking at both of the chassis side by side it's hard to compare details like we are attempting to do. I think we can both agree that both are competent designs and neither is a wet noodle like say a Miata (even the newest one isn't that stiff).

Speaking of bracing. The later second gen Miatas got an underbody brace that tries to box up some of the bottom of the car. It is somewhat panel like because it does much of it's work in tension but it's also beam like because it can withstand some measure of compressive load. Because it's a relatively (not entirely) flat peace and because it bolts to the chassis it doesn't do much for loads that would cause it to bend at it's connection points.

JonBoy

Fair enough. My biggest point was to show that there are two ways to get it done in this particular case, not necessarily as an overview of the entire chassis.

You're absolutely right that pretty much every chassis uses both types of reinforcement. Lightweight panels can add a LOT of structural resistance to a chassis for very little weight but they aren't particularly good in torsion. That's all I'm trying to say. In other words, they should be very much secondary, not primary, structural members when it comes to fairly obvious and direct loads (such as torsion on a chassis).

The Miata is a hoot to drive but I agree - it's not nearly as stiff as the S2000 feels. Maybe it's more about suspension tuning but I really don't know - haven't driven one long enough to figure it out.

tonyg11

reviews like that are stupid. Im not going to review a Formula 1 car and complain about the trunk space, the loud noise and the harsh ride.

When you review something, or write any type of article you cant forget one important thing. CONTEXT. And that reviewer had none