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The Stigs fat American cousin
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Discussion Starter · #1 · (Edited)
are halo style cages legal for SCCA rally, considering all other requirements are met? I am working on a car with a heavy duty cage of excellent construction (1.75"x.120" DOM Mild steel) however the cage design incorporates a "halo" style roof support (instead of a traditional "front hoop" ), I'm sure I can get the required data to support the design will qualify for section 5.6.M however to support that rule I'll require Stress mockups therefor the assistance of an engineer is needed, I really do not feel like adding that cost into the car build.

does anyone have experence with this?

Thanks,Jeff



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I am not here anymore
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I have no experience with this and am definitely not an expert, but according to the rule book, in Article 5.6.L.2, "a similar hoop (similar to the main roll hoop) must be in front, supporting the roof and front pillars with horizontal bars connecting the front hoop to the main hoop at each side of the top." If a halo design is what I think it is, this rule would preclude the use of a halo design.

alan
 

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don't cut
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Email Doug Robinson. He is the newly crowned SCCA Chief Scrutineer for rally cars. I met him at CT, he's a good guy, and he knows his stuff. You can mess around with opinions and speculations but a simple clarification from him will solve everything. As I understand, when it comes to scrutineering, his word is final. I don't have any contact info, but if you call SCCA I'm sure they can furnish it.

And by all means, keep us informed of the results!

Dennis Martin
[email protected]
920-432-4845
 

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Lovell's Subaru passed tech at CT with a "halo" front cage, plus much triangulation at the top of the A-pillars and in the unique design of the main hoop.
Anyone have photos of it to share?

gb
 

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The Stigs fat American cousin
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Discussion Starter · #6 · (Edited)
for those not familiar with the halo, here is a similar design

http://www.bryanf.com/mycars/yf/chassis.htm

I will get pics ASAP.

And John V, Yes we are fabricating a trick custom cage however the halo bar and main hoop were fabbed and welded together on saturday, I'd hate to start over due to an oversight.



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Looking at the pictures of that cage, I dont see anything that would prevent it from passing, so long as you put a brace at the front corners. A brace from the halo to the front A pillar bar would do it.


Brian
 

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Very good question, Don. I was wondering that, also. Maybe the load in a rollover is better spread out through whole structure?

Ok, you engineering types out there, tell us why.


GB the GG
 

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The Stigs fat American cousin
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Discussion Starter · #13 · (Edited)
it is in fact legal

here is the offical word from Doug.

"This type of cage is legal with proper gussets. I would suggest gussets on both side of any tube that supports the halo. The taco shell style gusset is what I see the most on this type of construction. If you need a source for this type of gusset try McKenzie's 714 441 1212.
Doug"

as far as the advantages, the front bar can be located quite a bit closer to the roof, this helps visability, It seems pretty strong too. but I would like a engineer to give us the technical info.

Jeff Lloyd
Ilp performance
Driver, Head Lacky
www.ilpperformance.com


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400 flat to crest
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RE: it is in fact legal

print out a copy of your email when you go to get your logbook. some people might be sticky if they don't see the design

One thing which I think they are trying to do is deal with the extreme windshield rake and the long run from main hoop and the floor with almost no bend, kinda weak looking in the traditional layout, hence the tubes running upward here and there.















John Vanladingham
 

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RE: it is in fact legal

JEEZ,

Now doug is giving away my tricks on the internet! ;-)

Yes, Halo bars are legal, and I believe it says so right
in the rule book if you read it carefully. The part that
McKenzies sells is called a formed gusset. It is designed
to work with a 90 degree T of 1.5" tubes. You can modify
them for other angles with grinding / cutting.

As for the advantages. I think there are several. First it
eliminates the head banger problem that many corner gussets
present. You can be a bit more creative about making a more
recessed cage with a halo bar than with those long straight
runners. In lots of cars those straight runners droop down
quite far.

Now you only have a nice radiused tube, recessed all around.

You can also argue that they are better able to take a
typical rally rollover load. That load is applied at an
angle, not straght down or over.

I think that windshield / A-pillar gusset area is one of the
most critical on the car. You can really spread the area out
with one gusset on each side, reducing stress.

To make that double gusset trick work the A pillar bar had to
take a slight bend to meet the outer radius at a right angle,
right in the middle of the bend. Perhaps some pics would help.

paul timmerman
 
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