heymagic Wrote:
-------------------------------------------------------
> You need to put the taco style gussets in, tubes
> are notlegal.

Well, they are for a NASA cage, but then you'd need to put
in a whole bunch of other stuff, like sill bars and rear
diagonals and windshield bar gussets. So it's probably easiest
(and cheapest) to do what Gene says and taco 'em.

---

Self-righteous douche canoe

The bent X door bars I've seen have been carefully welded along the junction between the upper and lower tube (usually a good foot or so of seam weld), and tied together with large gussets. TBH, I think good fabrication skills on either style should make for a safe cage, and vice versa.

Also, to my eye, a good tight joint and weld job on a bent-pair X should maintain the "tension".

Here are some photos of Larry's car (stolen from flickr without his permission).

As I read the various rulebooks, a single sill bar and a single diagonal doorbar meet the letter of the rules -- though I can't say I've seen a car built that way recently.

---

Pure mathematics is the enemy of every truly creative man -- Sir Alec



Edited 1 time(s). Last edit at 04/07/2009 08:40PM by Ted Andkilde.

Jon Burke Wrote:
-------------------------------------------------------
> also, I noticed you don't have the other X-brace
> that I've seen on some cars that goes from the top
> of your b-pillar junction and ties in back to the
> top of the rear strut towers. Is that a FIA
> thing? Or just extra safety-super-baller "I've
> got an extra 10 feet of tubing so I'll make
> another X with it" option?


A X-brace in the rear backstays has never been required by the FIA. A single diagonal back there used to be a valid substitution for a diagonal in the main hoop, but that changed in 2002, well before the FIA regs were adopted here.

At least one diagonal was required there in the old SCCA rules, and that is currently still true for the NASA rules.

---

Self-righteous douche canoe



Edited 1 time(s). Last edit at 04/07/2009 08:46PM by hoche.

Ted Andkilde Wrote:
-------------------------------------------------------
> Here are some photos of Larry's car (stolen from
> flickr without his permission).
>
> As I read the various rulebooks, a single sill bar
> and a single diagonal doorbar meet the letter of
> the rules -- though I can't say I've seen a car
> built that way recently.

I don't know who Larry is, but I hope that car's already logbooked
cuz otherwise he's got some more welding to do.


For NASA: needs A-pillar reinforcement bars and maybe windshield bar gusset (can't tell from those photos)

For RA: Needs A-pillar reinforcement and gussets, and X in main hoop with gussets. Oh and those plate gussets on the doorbars wouldn't be legal. Need tacos.

---

Self-righteous douche canoe



Edited 1 time(s). Last edit at 04/07/2009 09:07PM by hoche.

NoCoast Wrote:
-------------------------------------------------------
> From what I've heard, it happened in one accident
> where had the occupants not died from the head
> injuries, they'd have died from the blood loss
> from femoral artery being stabbed by a broken X.

I still wonder more about the quality of the gussets than the design of the 'x'

> Post that accident it's become recommended in the
> US, though I've not seen it widely implemented by
> people outside the US from pictures I've seen.
> However most of the 2006 and newer model cars FIA
> cage kits do use the bent tube method.

I have yet to see even one - please correct me if I'm wrong - of those FIA cage kits with 'inspection holes' in the door bar 'x'... not one!

>
> Grant Hughes
> www.nocoastmotorsports.net
> Denver, CO

tipo158 Wrote:
-------------------------------------------------------
> Right now, the FIA Institute recommends the
> continuous upper and lower "X" bar over the split
> "X" bar. They see more wrecked cages than I will
> ever see.

Oddly enough, they don't mention anything in Appendix J Article 253, not even on the new version that just came out three weeks ago.

---

Self-righteous douche canoe

hoche Wrote:
-------------------------------------------------------
> tipo158 Wrote:
> -------------------------------------------------------
> > Right now, the FIA Institute recommends the
> > continuous upper and lower "X" bar over the split
> > "X" bar. They see more wrecked cages than I will
> > ever see.
>
> Oddly enough, they don't mention anything in
> Appendix J Article 253, not even on the new
> version that just came out three weeks ago.

The FIA Institute are the research and testing guys and are different from the guys making the rules.

I tried to download the latest Art 253 and I got an error.

Larry is on here so may be able to speak to that a bit better, pictures may be mid build. Car is logbooked and has run a few RA events.

t

---

Pure mathematics is the enemy of every truly creative man -- Sir Alec

tipo158 Wrote:
-------------------------------------------------------
>
> I tried to download the latest Art 253 and I got
> an error.

The changes are really minor:
6.2 One bolt for two shoulder straps is now explicitly prohibited
8.3.2.6 Limitation on the bolt pattern for the foot in diagram 253-50
14.3: They claim there was a change here, but the wording looks exactly the same to me.

---

Self-righteous douche canoe

Ted Andkilde Wrote:
-------------------------------------------------------
> Larry is on here so may be able to speak to that a
> bit better, pictures may be mid build. Car is
> logbooked and has run a few RA events.
>

Ah, if it's logbooked (and I'm guessing it has a NASA logbook), it wouldn't
be a problem. NASA only started requiring the A-pillar reinforcement bars in new
cages this year.

---

Self-righteous douche canoe

Ted Andkilde Wrote:
-------------------------------------------------------
> The bent X door bars I've seen have been carefully
> welded along the junction between the upper and
> lower tube (usually a good foot or so of seam
> weld), and tied together with large gussets. TBH,
> I think good fabrication skills on either style
> should make for a safe cage, and vice versa.
>
> Also, to my eye, a good tight joint and weld job
> on a bent-pair X should maintain the "tension".
>
> Here are some photos of Larry's car (stolen from
> flickr without his permission).
>
> As I read the various rulebooks, a single sill bar
> and a single diagonal doorbar meet the letter of
> the rules -- though I can't say I've seen a car
> built that way recently.
>
>
>
> Pure mathematics is the enemy of every truly
> creative man -- Sir Alec
>
>
>
> Edited 1 times. Last edit at Apr 7, 2009 by Ted
> Andkilde.


That's not an X bar, that's more like a "U" bar or something. So it doesn't really do much for triangulation. And it still has the problem of neither of the bars being in tension, if that's something that concerns you. And there is only a flat plate (looks like sheet metal, more like) gusset on one side so that is not really doing much, just there for looks, mostly. It should wrap all the way around.

tipo158 Wrote:
-------------------------------------------------------
>> As far as I have seen, many door bars were add-ons
> to existing cages and did not go through a logbook
> inspection. The first time a tech inspector saw
> them, they were painted and maybe even covered
> with padding. It is harder to evaluate the
> quality of the weld under those conditions.
>

Well then the tech inspectors need to look a little harder to weed out poor work. I know I've made people take off taped over roll bar padding when I suspected it was hiding crappy welds (and it was.)


> Right now, the FIA Institute recommends the
> continuous upper and lower "X" bar over the split
> "X" bar. They see more wrecked cages than I will
> ever see.

Doesn't mean they're right. They may be trying to prevent one issue and inadvertantly creating another, I dunno.

>
> I have heard of split "X" bars failing as
> described. I don't know if they were gusseted. I
> don't know the quality of the welds. I do know
> that that kind of failure is a lot more possible
> than with continuous upper and lower bars.
>

Most likely when that has happened is was with chromoly tubing. Much more likely to happen with that then DOM.


> Do split "X" bars have an advantage over
> continuous bars?
>

Did you even read the part where I said the the continous bar setup has neither of the bars in tension? Apparently Mike Hurst thinks this is important. The intersecting X always has one bar in tension.


> Finally, recall that I recommended that he
> "rethink". He might do so and decide that the
> risk is comparatively low and stick with what he
> has. Another option would be, particular since he
> needs to make a bunch of taco gussets anyway is to
> add them to the top and bottom of the center of
> the door bar.
>

I wasn't speaking specifically to his car, but he does need to box up those gussets. Actually, they are not even really gussets, just short tubes welded perpendicularly to the main bar.

> As far as the split vs. continuous X bar, I don't
> think that you described the continuous bar as I
> have seen them done in practice. However, I don't
> have time to get into a big discussion.
>

The style of continuous bar I'm talking about is the kind that you see in the WRC Subarus and such.

V door bars appear on FIA Homo cage kits for 06 and newer Evos and Subarus.

---

Grant Hughes

OK, so I took a deep breath, and all is good.

As far as changing over to a Taco style gusset, what is going to be the acceptable method? can I make some triangles and fill in the area using the tube gusset as the "wrap around", or do I need to overkill it and overlay a Taco?

You need sill bars below the X brace on the doors.



Edited 1 time(s). Last edit at 04/09/2009 03:17PM by BillyElliot.