Roll Cage Design

[BigKeyserSoze]

I am going to add a second bar to my roadster to make it safer in the event of a rollover. I thought a few years ago, Karen and others posted the diagram on what they built, but I searched for a while and can not find it. I did find other posts on the subject and read them with regard to making sure the helmet does not hit the new bar.

Can anyone either repost or redirect me to where that is? Also, there are two different designs from what I remember. The kind like Tim Konkol runs, which is a bit closer to the main hoop, and the type like on Boothmans #85, there the bar is farther from the main hoop. Would love to see designs on both.

Thanks in advance.

[vnmsss]

The design we used was based on the one Dave Standridge installed on the #83 car. We talked to him on the phone and he walked us through the measurements....Ed's cage on the #85 was added in the same fashion, as that car was maintained by Dave/Rennwerks at the time.....I could be wrong, but I thought Tim's car was also a Rennwerks car, and that it was raced by Tasha Standridge...The cage might be a bit different, or a later iteration of Dave's design....I believe Rich Norgrove (Racer #5) has the same bars added to his car as well. (All three cars in pic below...Now that I'm looking at it, Tim's side support bars might be on less of an angle than mine)

I took a pencil drawing over to a local fabricator (Dave Schiedecker, stockcar guy with 40+ years experience) over in Fontana near the speedway, and he fabbed up our bar......The biggest thing for me was the importance of the location of the overhead bars (front to rear pieces connecting the new bar to the stock bar), as well as the importance of the "new" bar being visually blended-in on as close to the same plane as the existing bar as possible......Dave did a great job.

I'd be glad to do some measurements and draw something up if that would help....I'd send you to see the #85 down there in Naples, FL, but it's sitting here in my front yard....;.)

Karen

[ffspecracer]

Sent you an e-mail with pics.

[johngeorge]

Scott, you could also do something like what Dobyns did on Wayne's car:

[DrAwender]

Originally Posted by ffspecracer

Sent you an e-mail with pics.

I want to be just like Tim and have my name visible on my videos too.. Could you email me what you have as well.
J

[ffspecracer]

PM me your e-mail addy and I'll send em out.

[BigKeyserSoze]

What bar size is everyone using for the additional cage material?

[M DOUGHERTY]

1.5 dia. .120 wall DOM

[ffspecracer]

What Mark said........has to be the same as the rest of the cage.

Pay particular attention to the DOM, no ERW. ERW has not been allowed since 2003.

[cobra728]

SCOTTY!!!

I remember that post with the drawings and specs for the "half cage".

Yet another perfect discussion for Dave Standridge...Daaaaaaaaaaaaaaave, wheeeeeeeeeeere the Heck aaaaaaaaaaaaaaaaaaaaaaaaare youuuuuuuuuuuuu?

I was looking for that post today, couldn't find it, its like Ragu...its in here.

I can not recall the post name, topic, or who dun it. But I specifically remember it.

Idea:

Call Rennwerks, located in Campbell CA. That's Daves old place, maybe they have the drawings from it. Maybe they have one laying around.

Hope all is well with you, the boy is probably getting big and into everything, and give your wife a hug for me.

And last...the count now stands at 15 cases.

[cobra728]

And yes, my car was Tasha's and it is a rennwerks car as Karen says below.

Happy new year everyone.

[Ed Gaven]

Scott, Check EvilGenius.com, click on Factory Five and there are some pic's of my cage. We used the diagonal down tubes to add a higher door bar. Mikee has yet a different arrangement. I would not have changed the original, except to meet Pikes Peak requirements. Regards, Ed

[MarkMc26]

OK, I'm about to get involved with the cage addition on Scott's car. I have been studying and over-analyzing dozens of different cages over the past couple of years, as I have slowly built the cage for my 2004 Mustang (I have nothing but spare time these days) in an attempt to have "no regrets" with the final product. Along the way, I have learned that many "cage fabricators" just weld tubes together with little regard for what the tubes are actually doing once they are in place (aka load paths). A few fabricators are familiar with the basic engineering principles, though.

@ Ed Gaven: I found this link, and I believe that it is your car: FFRC #62 at Pike's Peak, 2010. If so, then was this modified cage design approved by FF for FFRC competition, since the diagonal side bars were removed? I must say that this is probably the best FFRC cage addition that I have seen, as (in my opinion) the other ones that just sit on top of the side diagonal bars, with no additional/matching supports below the side diagonal bars, do not seem like safe alternatives in a roll-over. The cage in the #62 allows ingress/egress both through the top of the cage and out either side, which is good. Personally, I would only add a little extra triangulation or gusseting, but that's just me.

Is this your car as well?


I don't see why more cars don't have the A-pillar bars moved further forward, as shown on the #62 and is done on sprint cars, Thunder Roadsters, etc. At 6'-2", I'm a little shorter than Scott (although I'm a good 30 lbs lighter), and I would have a hell of a time getting in/out of the car with the cages that only extend a foot or so ahead of the main hoops. Throw in an emergency situation, an injury, an extrication, or any other precarious condition, and the egress wouldn't improve. Having the option to exit via the top or the sides seems like a good idea to me.

EvilGenius.com seems to be down at this time.

Mark

[McMahonRacing]

This may be the cage post you were looking for:

Modified Cage Mockup- edit -the answer is ?

The cage design we settled on can be found here:

www.patmcmahonracing.com
under:
Past projetcs ..... FFR_Spec_Mod_Charlie

an alternative but similar design can be found here
www.patmcmahonracing.com
under:
current projetcs ..... FFR_Spec_Mod (# 67 A )

Mind you these are alternative designs, one of which was based on a very very early MKI or II that was converted to Spec Legal, so the design should be considered legal but heavy for the Spec class.

Pat

[ffspecracer]

Nothing of the original cage can be removed! So no, the side diagonals must remain.

As for the new hoop "sitting on top of the diagonals," many of us have added bars below it to tie it to the frame thus making it rigid.

[DrAwender]

I have already been working on adding a full cage, just haven't had the down time yet. You CAN remove the diagonal brace, however your design must get FFR approval and NASA. However to make your life easier, get FFR (Jims) approval first then you can get the ok from NASA. Basically your design must meed FIA and or generally accepted current cage requirements.

"3.2 Cage/Rollover Protection
All cars must utilize the factory rollover protection system. The system may not be modified without written approval from NASA. In any case, all cars are required to maintain the rollover protection structure to the most current standards, unless otherwise specified in writing by NASA. Notation must be made in the car logbook indicating NASA approval of the modifications."

I have the 2011 FIA hand book for cages if anyone is interested, just PM me.

Looking at the picture, as long as you are using the proper size tubing, your design meets all FIA rules and would be perfectly legal.


J

[ffspecracer]

So it would appear that a deletion to the original cage has been granted in the past. I was not aware of this. I stand corrected.

Bottom line, each cage must be approved by NASA and one should seek approval before doing ANY modification.

[MarkMc26]

Originally Posted by ffspecracer

As for the new hoop "sitting on top of the diagonals," many of us have added bars below it to tie it to the frame thus making it rigid.

Agreed; I made that comment because the first 2 photos in this thread show the new cage structure sitting on top of the un-reinforced diagonals (lest anybody think that it's a safe solution).

Mark