Cage tubing question (Page 2 of 3)

Thanks for posting these pix, they are very helpful. ALL THREE OF THESE DESIGNS ARE LEGAL. The "continuous" language is a little tricky--but one-piece front hoops, left/right hoops, and "halo" designs are all acceptable. What we want to avoid are main structural elements of the cage being made of sectioned-together pieces of tube.

Bolt-up Autopower cages like this are also legal:

It's highly recommended but not required to weld the bolt-up sleeves (there's really no reason not to weld these, though....).

We understand the confusion surrounding the "continuous" wording--we may indeed tweak this. Basically, what we're trying to avoid is any of the main load-bearing members of a cage being made from sectioned-together tubing.

As far as getting 360-degree welds up top--cutting access holes in the roof may indeed be the best bet. I can't really be more specific than that due to varying cage/roof/a-pillar layouts.

Nick

Thanks very much for clarifying this point, I know we are pains in the .... but
remember we are your Pains... until we can no longer capable of driving a car and for me that's going to be a long time!

Thanks Paul

Knights of the round track.

Yes, that's correct. We now know we were too vague on the language there, so thanks to you guys for giving us the heads up. (Even though it was in the patented Lemons guy "panic speech," but that's why we love you guys. You're passionate.)

Thank you Nick.

The continuous part isn't the tricky part - it's the "Full front ... hoop" that is the sticking term in the rule.  That is what is making the design hard.  Doing a cage that way is the worst of all worlds... 

I really hate to point to another organization for rollcage specs but you could look at the SCCA GCR but paraphrasing the IT rollcage rules:

Main roll hoop (behind the driver) shall extend the full width of the driver/passenger compartment, shall be as near the roof as possible, and shall be made of one continuous tube. It shall incorporate at least one diagonal lateral brace to prevent lateral distortion of the hoop.  It is required that a horizontal brace behind the driver’s seat continue from the diagonal to the passenger side main hoop upright or that a second diagonal be installed in the main hoop (this is currently optional in theLeMons rules but makes the main hoop much stronger).  The main roll hoop shall have two unbent braces extending to the rear attaching to the frame or chassis. Braces shall be attached as near as possible to the top of the main hoop and as close to 45 degrees as possible. 

The front or side hoops shall follow the line of the front pillars to the top of the windshield (as close to the roof as possible) then horizontally to the rear attaching to the main hoop. These two side hoops are to be connected together by a tube over the top of the windshield, or
a front hoop following the line of the front pillars and connected by horizontal bars to the main hoop on each side at the top may be used, or a top “halo” hoop following the roof line from the main hoop to the windshield with forward down tubes following the line of the front pillars to the floor.

Two (2) side tubes connecting the front and rear hoops across the drivers door opening are mandatory. NASCAR-style side protection, or one bar bisecting another to form an “X” is permitted.

Lemons is not the first organization to mandate rollcages.  All I did was look in the SCCA GCR and paraphrase some rules.

I think it was more of a kerfuffle verging on mutiny.

Bingo.  We put holes in the floor up front and leaned the cage forward to weld everything up high.

Removing the front glass made this a bit easier as well.

We actually boxed our rails at the tube interface point to stop punch through on the top and colapse of the side-wall.

EWR is very easy to find here in Portland, and it costs less than half of DOM.  The point should also be made that for many teams the weak points will be the crappy welds and not the tubing, anyway.  We're also almost all driving very light cars and the likelihood of bending any of this tubing to the point of any danger is very, very small.  The rollovers we've seen highlight this point - as far as I know there has been no cage failures of any kind.  Anyone else want to chime in?  The B210 at Thill 08 would be a prime example, that car took a beating.

Floorplates ? How thick should they be? I've been doing overkill of like 1/4 "

What we did last year and what we're planning on doing this year is building a cage as close to NASA specifications as practical.  The NASA rulebook is very specific about advised ways of joining tubes, making floor plates (how much area, max/min lengths per side), mounting things, choosing materials, etc.  Just make sure that in the few areas where NASA isn't as stringent as Lemons (tube sizes for light cars) you use the Lemons value.

The rollcage stuff is section 15.6, which starts on page 59.
http://www.nasaproracing.com/rules/ccr.pdf

I usually like I said  before build  Crawlers and desert truck so we have frames to weld to ,so backing plates was new to me and I always build too big

Who do we ask for waivers or grandfathering requests of? I've asked this before of the Grande Poobah. Should I just send him a request again?

Thanks.