theoretical roll cage question

[RacerBill]

We are allowed to use a mounting plate not more than 100 sqi in, correct? But the plate does not have to be square. My question is, if I were to lengthen one side and shorten the adjacent side (assuming that I wanted to keep a rectangular shape), would it be more advanageous to lengthen the longitudinal (length of the car) side, or the lateral (across the car side).

And I don't want to hear any of this 'it depends' stuff! If 'it depends', please explain what it depends on!

Thanks.

[Knestis]

It depends.

Think about this: The better answer might be to think about wrapping the plate onto more than one plane, like from the floor up the rocker panel. I aimed for important looking corners in my bodyshell and boxed over an area not exceeding 100 sq in so , in some cases, they wrap across 3 planes.

K

[joeg]

It depends...

With absolutely no other considerations (available sills, rockers and vertical structures) my guess is that favoring longitude (lengthen along the wheelbase) rather than "latitude" (lengthen along wheeltrack) may have an infinitismal stiffening benefit. Why? there is usually less distance to the floor tunnel than between front and rear firewalls.

[RacerBill]

Thanks, guys. Of course, it depends! Everything depends on something. Thanks for going along with that.

K: I am definitely looking at bending the plate and welding it to a vertical surface. I just wanted to keep the question as simple and theoretical as possible.

Joe: You are saying that increasing the length of the plate across the car would be better than from front to back because the amount of increase will be a larger percentage of the distance between major structural members?

[cagedruss]

If I remember correctly, you are allowed to have a 10"x10" maximum. which equals 100" sq in. The rules say you can not have any one side longer than 12" and no narrower than 2". Also if you use multi planes on the plate, if the plate was unfolded flat, it would have to fit in side the 10x10 box. use as much as you can on the rocker, floor, and sill. But be careful not to make the plate to big. I would hate to see you get protested by someone!

[This message has been edited by cagedruss (edited January 13, 2004).]

[Geo]

Originally posted by cagedruss:
If I remember correctly, you are allowed to have a 10"x10" maximum. which equals 100" sq in. The rules say you can not have any one side longer than 12" and no narrower than 2". Also if you use multi planes on the plate, if the plate was unfolded flat, it would have to fit in side the 10x10 box. use as much as you can on the rocker, floor, and sill. But be careful not to make the plate to big. I would hate to see you get protested by someone!

[This message has been edited by cagedruss (edited January 13, 2004).]

It does not need to fit in a 10x10 box. You even said yourself that it can be 12" max on one side.


------------------
George Roffe
Houston, TX
84 944 ITS car under construction
92 ITS Sentra SE-R occasionally borrowed
http://www.nissport.com

[badal]

If I were you, I would use a piece of thin cardboard, like a manilla folder to make a pattern.
The more planes it can attach to, the better from a safety and performance standpoint.


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"Bad" Al Bell
ITC #3 Datsun 510
DC Region MARRS Series

[joeg]

No--I said front to back could be theoretically better (infinitismal, however).

Cheers.

[Knestis]

I also don't believe that it is practically necessary for the "plate" to be one contiguous piece of sheetmetal: It can be a fabrication made of a number of individual pieces, the sum of which doesn't exceeed 100 sq in.

K

[RacerBill]

My thanks to all the responses. At least I will not be stabbing in the dark when it is time to fabricate the plates. I have every intention of using vertical surfaces where ever possible.

[wayno]

Hi Bill,

What are you building and when is your first outing?

Wayne

------------------
Wayne Briggs
CenDiv
ITA Capri
Building a SM
Move...Lest Ye Rust!

[Russell]

I used a sheet of 8 1/2" x 11" notebook paper as a template for my plates. As long as all of the pieces fit on one sheet of paper, you are golden.

[ddewhurst]

Russell, ya gave up 6.5% Square inch area of each plate.

Have Fun
David