Grumpy

STEP 1.The MAIN HOOP

First I determine the tubing size required. I'll need a couple of holes drilled, not larger than 3/16" in each tube I want to measure.

ISSUES:

Inspection hole too large.
Wrong tubing material.
Wrong tubing wall thickness.
Wrong tubing outside diameter.

Next I look at the floor mounting.

ISSUES:

Poor welding/penetration/heat
Floor gusset plate size. Too big/too small.
Proper attachment to floor, frame, channel rail.
Condition of floor of car. Rust. Damage.
Full circle welding of tube to gusset plate.
Full welding of gusset plate to floor. bolt size/quality/amount
Proper backup blates under floor of car.

Then I add up the bends in the main hoop.

ISSUE:
The Aggrate total of all bends in the hoop CANNOT exceed 190 degrees.

Check the bends.

ISSUE:
Must be done with mandrel bender.
Even so must be no crimping, no ovalling.
The diameter of the bend should be greater than three times the thickness of the bar.

Keep looking.

ISSUES

Must be one piece.
No more than four bends.
Must go all the way to roof.
Must be full width of car.


And that's just the main hoop.

Should I continue???

tnord

continue.......i'm interested.

Grumpy

I forgot step 0.

Give the car and cage a quick once over.. Would I want to crash in this car? Does the GENERAL structure of the cage look like it will support a front hit, rear hit, barrel roll, 3/4 front(rear). side hit, MULTIPLE HITS?.

The general cleanliness of the car and the cage usually is an excellent indicator of the strength of the cage.

D.CACO

More, more, more!

krshultz

I'm interested in your assesment of side-impact protection. My thoughts...

- NASCAR bars? If so, adequately reinforced? Too many bends? At bumper height?
- If no NASCAR bars, is door bar high/low enough?

Also interested in your assesment of "intrusion into the driver's space" for lack of a better term. I know with my old bolt-in that passed in front of the dash, any hard driver side impact and I would possibly break my arm/wrist on the a-pillar bar, which was amazingly close to the steering wheel.

When a cage gets teched, does proper design get assessed, or is it simply "it passes by the letter of the logbook?" Does this vary from inspector to inspector?

Inquiring minds want to know.

--Karl, off to go grill up some salmon...

ZygSpeed

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by krshultz &raquo;</TD></TR><TR><TD CLASS="quote">When a cage gets teched, does proper design get assessed, or is it simply "it passes by the letter of the logbook?"

Does this vary from inspector to inspector?</TD></TR></TABLE>

If you can't rely on "letter of the rule book", then what can one rely on?

... because on appeal not much else counts!

krshultz

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zygspeed &raquo;</TD></TR><TR><TD CLASS="quote">

If you can't rely on "letter of the rule book", then what can one rely on? </TD></TR></TABLE>

Well, there's legal, and there's good. There's a difference.

Grumpy talks about mounting plates on the floor of the car for example. They could be too small (and potentially punch through the floor in a serious rollover). They could be too large - safe and stout, but perhaps not legal. Grumpy might not know/care about the 100 square inches of floorplate you're allowed per attachment point...he has to just assess safe versus dangerous.

Jim, is that about right? You're the expert,don't let me put words in your mouth.

ZygSpeed

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by krshultz &raquo;</TD></TR><TR><TD CLASS="quote">...he has to just assess safe versus dangerous.</TD></TR></TABLE>

I totally respect that, and don't wish to belabour (GK reference) the point, but ... technical issues need to meet the letter of the rules, not necessarily someone's "impression" of what is right.

There's a reason why it might be 100 sq. inches (not more or less) otherwise it's unsubstantial and will push through like in an old Mini, or people will weld in bracing covering a quarter of the car.

I could go on ... about the alleged rollbar/race belt rule in HPDE's with NASA in the previous years, in as much as it was apparently a "good thing" but not found anywhere in the rules in effect at the time.

REFLUX

very good thread!
more more more!!!

George Knighton

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zygspeed &raquo;</TD></TR><TR><TD CLASS="quote">

I totally respect that, and don't wish to belabour (GK reference) [sic] the point, but ... technical issues need to meet the letter of the rules, not necessarily someone's "impression" of what is right.</TD></TR></TABLE>

Most legal documents related to issues like this include a common sense disclaimer to cover issues discovered at the scene.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITR Expo Rules &raquo;</TD></TR><TR><TD CLASS="quote"><FONT COLOR="blue">
These rules are in addition to, and not in derogation of the rules of common sense and exigencies that might arise at the scene. These simple rules in no way constitute the entire scope of how the event will be run, and the organisers reserve the right to implement rules on the scene as needed, refer to the NASA CCR for advice, or invoke and enforce a summary judgement based on circumstances that exist at the time.
</FONT></TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HAN TOS &raquo;</TD></TR><TR><TD CLASS="quote"><FONT COLOR="blue">
Any rules we institute are in addition to and not in derogation of the rules of common sense or the law of the land, nor can any set of rules replace the law or provide for every exigency. The simple rules we write here can in no way constitute the entire scope of how the board will be managed. We can only provide the guidelines.</FONT></TD></TR></TABLE>

You know you're at that paragraph when you're writing a statute when you get to saying:

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">However nothing in this Act shall extend or be construed to extend to enable....</TD></TR></TABLE>



<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Papa Johns HR Guidelines (c)GK 2003 &raquo;</TD></TR><TR><TD CLASS="quote">
These rules shall not be construed to be exhaustive and the directors reserve the right to make necessary amendments as required by discovery of unknown issues or changes to the law. These changes shall take effect on the discovery of the directors, and no notice is required.</TD></TR></TABLE>

Grumpy

I'm back and it seems like we will continue. Many have gone way ahead and I will eventually catch up. So far we are looking at the main hoop and its attachment to the car.

Comments questions on the main hoop???

By the way when NASA and SCCA differs I will attempt to discuss the differences.

I make no inference to any rules other than these.

Grumpy

Oh, and I am limiting this discussion to SS/IT SCCA cage rules and NASA rules and HC modifications.

Grumpy

If a cage meets the specifications of the rule book EXACTLY its design is thereby approved.

If a cage deviates from the specifications of the rule book the design is subject to approval.

Grumpy

Safe vs. legal.

A technical inspection checks a car for safety not class compliance.

A protest or a spot inspection checks a car for class compliance and/or safety.

A tech sticker is given on the basis of a tech inspection not class compliance.

If the plates under the main hoop are too small, that is a safety concern. NO TECH STICKER FO YOU!

If they exceed 100 sq. inches you get a tech sticker, as it more than complies with the saftey issue, but you can get DQed on a class compliance inspection.

Wai

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grumpy &raquo;</TD></TR><TR><TD CLASS="quote">
Wrong tubing wall thickness.
Wrong tubing outside diameter.</TD></TR></TABLE>

Grand Am allows FIA-spec cage with 40mm x 2mm thickness, which equals to 1.575" x 0.0787". Would NASA-VA also consider that as acceptable? I'm not sure about SCCA since I don't have their GCR (can't be downloaded, needs to be purchased).

Grumpy

Cages made to other sanctions specifications may be approved by NASA.

Cages made to NASA specs with this FIA tubing in place of 1.5 x .095 is not.



Modified by Grumpy at 4:45 PM 6/26/2004

k279

What is the fia tubing you are talking about. chromoly? mild steel? and is the 1.5 x .095 the smallest size? and how about a pillar bars, info? im learning tons.

Wai

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by k279 &raquo;</TD></TR><TR><TD CLASS="quote">What is the fia tubing you are talking about. chromoly? mild steel? and is the 1.5 x .095 the smallest size? and how about a pillar bars, info? im learning tons. </TD></TR></TABLE>

Since we're mostly talking about Honda Challenge, I was referring to the FIA rollcage made for Honda (~2000 to ~2500 lbs). Like the ones made by Mugen for DC2, EK and DC5. From the info I got from King, the FIA approved cage for DC2 and EK is 40mm x 2mm seamless steel.

slammed_93_hatch

ok i know the first and formost purpose of a roll cage is saftey but what about stiffing the chassi up. i know there was a thread with a couple great links to roll cage design mostly european stuff. but it REALLY HEAVILY focued on triangulation, now i have NO clue if this would be legal or if it would even help. but i got to thinking about were a triangle could go on a roll bar which might be helpfull.

now the lime green is what im talking about, this is just to give a general idea of what i was thinking of. Any input?]

Wai

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">now the lime green is what im talking about, this is just to give a general idea of what i was thinking of. Any input?</TD></TR></TABLE>

That won't do much to stiffen up the area (maybe very very minimal). The purpose of diagonal or cross bracing is to transfer the load to the mounting points, then thru the bolts or welds to the rigid element like shock tower or floor pan.

When you draw the green lines, keep in mind the end of the lines should be connected to a joint, not to the middle of the pipes like what is shown. The way you drew it, all it would do is to put bending into the pipes --- relying on the bending stiffness of the pipes to resist load instead of using the more rigid elements like shock tower and floor pan.

The best way to do it is to put a X between the two rear legs like what we've been seeing on some rollcages.

Grumpy

Moving on to the main hoop supports, SCCA and NASA differ here as to legality. Both require two supports from the top of the hoop to the rear frame of the car.

SCCA wants them as near as possible to the to, not more than 6 inches below the top and at an included angle of at least 30 degrees. These braces cannot contain any bends.

NASA rules has all of the above PLUS a rule that says when viewed from the top the supports cannot be more than 15 degrees left or right of straight back.

This effectively disallows the "X" rear support system when used alone to support the main hoop in NASA. SCCA has specifically allowed this configuration.

My main objection to the "X" is that at the center of the "X" there is only one bar supporting the main hoop.

The other ISSUES are:

Complete 360 degree welding of all tubes
Proper gusset plates
Proper attachment of gusset plates welding/bolts/backup plates
inspection hole 3/16 inch
same size tubing as main hoop.

Going to Summit Point now for the SCCA regional.

Bling on! Yo!

slammed_93_hatch

ok that makes sense. so something like this?



and having the X connect to the shock tower or to another bar would be better? im going to say that it would be better to connect to the shock tower. lets see if i learned anything

davidnyc

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">ok that makes sense. so something like this?



and having the X connect to the shock tower or to another bar would be better? im going to say that it would be better to connect to the shock tower. lets see if i learned anything</TD></TR></TABLE>

This is essentially my cage. However, I have a box built by the rear upper shock towers and the X bars and shock tower bar is connected to them

Grumpy

The green X supports ALONE are not legal in NASA but are legal in SCCA.

Evan55

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Grumpy &raquo;</TD></TR><TR><TD CLASS="quote">The green X supports ALONE are not legal in NASA but are legal in SCCA.</TD></TR></TABLE>
Interesting, this would make Piper Spec Miata cages (and other Piper cages?)
illegal in Nasa. However, I know I have seen piper caged cars at nasa races.. so is this rule enforced ?