Roll Cage material ?

[Richie]

Is square tubing legal for use as a roll cage and if so would it if have to be 1 continuous piece ?   

[Dr Goggles]

Even if it was legal I doubt anyone who really thought about it would use it..........

When you smack your helmet on something you hope it doesn't have a sharp edge on it.

When you bend tube you want it to have the forces on it spread evenly, I don't reckon that happens with square stuff.

[dw230]

"What's the difference between experience and education ?"

The difference is reading, re-reading and asking the correct officials the question.

That said, the rulebook states that tubing, does not specify round or square, of certain properties must be used. Looks like you have proceeded without guidence.

I would change my consultant if I were you.

DW

[maguromic]

X2, I would run away from your consultant and hide till he/she disappeared. Tony

[Peter Jack]

What's more that appears to be aluminum tubing and I can pretty much guarantee that it won't make it past tech for any crash protection purposes and likely not as a main chassis material.

Pete

[Blue]

Experience without education is a brutal and imprecise teacher at best.  

Education without experience leads to impractical and un-buildable designs.

The experienced person lacking education will do the right thing because others did it before him even though he doesn't know why.  At worst, experience without education forces us to repeat past mistakes without learning from them.  The educated person will attempt theoretical perfection without regard to practical requirements like available tire and tubing size.

We need both.  The first thing I ask anyone who comes up with the latest-greatest idea is "how is everybody else doing that?"  If it really is a good idea, they can prove it's worth by comparison.  Likewise, anyone who gets into the trap of "we-do-it-this-way-because-we've-always-done-it-this-way" needs to step back from time to time and take a fresh look.

All of that said, roll cages should be made of round tubing for the simple reason that crash forces come from all directions, with multiple impacts that are not oriented to the structure we build.

[Captthundarr]

With all of the education and experience advice out of the way. NOPE square tubing won't cut it. The tubing specifications called out by most sanctioning bodies call for X.XX Diameter tubing = round. get a rule book and read,read,read then ask,ask,ask. GL

[Richie]

Even if it was legal I doubt anyone who really thought about it would use it..........         /   Why ?

When you smack your helmet on something you hope it doesn't have a sharp edge on it.     / padding and/or radius tubing might help?

When you bend tube you want it to have the forces on it spread evenly, I don't reckon that happens with square stuff   .\  i've bent both with a gas axe and i dont know bout the forces on it ... but it did bend   

[Richie]

The difference is reading, re-reading and asking the correct officials the question.   / I will... though who's to say there a 100% correct

That said, the rulebook states that tubing, does not specify round or square, of certain properties must be used. Looks like you have proceeded without guidence.      / true... like i stated in an earlier thread built that to get the shape of the body and to see if i could fit in somin that size.

I would change my consultant if I were you.   / na i don't have a consultant...  inspiration



DW

[grumm441]

Richie

It looks like you are building a motorcycle streamliner
If you have a rule book , you should look at rule 7.H.4

Roll Cage:
Shall completely surround the rider and shall be fitted in the rider’s compartment. Minimum diameter is 1-1/4 in. with .090 in. nominal wall
thickness, mechanical steel tubing. No galvanized pipe, black water pipe or threaded fittings are permitted. The design of the roll cage shall
incorporate the following features as a minimum: Two (2) roll bars, (one forward and one after the rider’s head), which shall be tied together and
capped with a steel plate .090 in. thick. The cap shall cover the upper 140 deg. of the rider’s head. The roll bar shall be braced with a tube of the
same dimensions on each side. Rider head movement shall be limited to no more than 2 in. to each side, top, or rear, with rider’s head in the
normal position. Roll cage padding meeting SFI specification 45.1 for round tube roll cage padding and SFI specification 45.3 for flat roll cage
padding is required in the vicinity of the driver’s helmet.
Forward movement: All motorcycle streamliners presented for inspection shall have an engineered and tested SFI
spec 38.1 type head and neck restraint system. All motorcycle streamliners shall have an engineered and tested SFI spec 38.1
type head and neck restraint system.
Lateral movement: Shall be constructed such that the helmet can not exit the outer plane of the roll cage,

You will note is states "steel tubing" so aluminum is out
The other thing you should consider is buying the correct roll cage padding and HANS type neck restraint, then working out if you fit in the cage

Also, I'm not keen the way the cross bar is made in sections. It think would be better to make the round section and weld the front to back bars to it.
G

[Richie]

 HANS type neck restraint   /   i'm not sure bout that , if u could make the cage and padding to prevent such movement ... why need that device ...  and round roll bars would be easier to produce ... and i was sure bout the aluminum structure, just cause the melt issue even if saddled by 1/4" plate   ...

[dw230]

"HANS type neck restraint   /   i'm not sure bout that , if u could make the cage and padding to prevent such movement ... why need that device ..."

Because the rulebook states that the item is required. There is no provision to not use one.

The officials have literly 100s of years experience combined. If you can disprove that with your design knock yourself out.

Good luck, and I really mean it this time.

DW

[Peter Jack]

Before you get any further into the build I'd be very tempted to run your design and material choices past the officials of the organizations where you plan to run. That way you won't have put in all the money and effort and find that you can't run where you want to if at all.

Pete

[Rex Schimmer]

I am always mystified as to why people build space frame type structures with square tubing. Is it because they are unable to visualize the tube joints using round tubing? With todays many types of various tools to cut and miter round tubing at almost any angle and providing perfect tube fits using square tubing seems almost inexcusable.

Rex

[Peter Jack]

I think it's because they think it's easier Rex. It may be if they aren't willing to tool up a little.

At the same time there are a few square tube based cars that are very nicely done and the results show it.

Pete