Roll Cage Information for GT40 Please

[Russ Noble]

Re: roll cage pictures please

Not the track then Jac Mac?

Must have been those biting cold southerlies then. Straight off the Antarctic ice shelf, must have frozen the brain. You locals would be acclimatised to it. Known as the unfair advantage.....

 

[Mark Worthington]

Re: roll cage pictures please

Since there are 20 replies to this thread and only Dean Lampe has seen fit to actually post pictures of his roll cage, perhaps I can point you in the direction of another thread that actually has some tech and pictures in it:

http://www.gt40s.com/forum/all-gt40/11591-roll-cage-safety.html?highlight=cage

I searched for pictures of the roll cage in Richard Timte's RF GT40. I've seen his car and it's spectacular, and the cage is particularly well done. Unfortunately, the links he posted are no longer active.

I hope Richard is OK. He's a tremendous asset to this forum, but it's been quite a while since he posted.

 

[Randy]

Re: roll cage pictures please

Dean, Thanks your cage seems like a good way to go. Your right about needing something if all goes bad. I'll even bet you use door brace at 150 mph. A little confidence builder.
Howard Thanks for the fire drill!! Are you using a 5lb system? Exactly where are your nozzles?
Randy

 

[Russ Noble]

Re: roll cage pictures please

Since there are 20 replies to this thread and only Dean Lampe has seen fit to actually post pictures of his roll cage, perhaps I can point you in the direction of another thread that actually has some tech and pictures in it:

With all due respect Mark, I notice that you haven't seen fit to actually post pictures either.

In post #2, I did post a link, in the same manner that you have done, to the particular pages on my build thread that contained photos that showed my roll cage.

A diligent search on "cage" would have thrown up this thread http://www.gt40s.com/forum/gt40-tec...eels/12872-rollbars-cages.html?highlight=cage which contains an interesting reply by Peter Ransom and also a link to the thread you linked to.

Cheers,

 

[Ron Earp]

Re: roll cage pictures please

Here are some pictures of my Lola cage. It is SCCA legal, built to GT specifications for a < 2600 lbs car. Your GT40 cage would have similar requirements but you'd need to imagine a halo bar with A-pillar down tubes in place of what I have, as well as two parallel front to back bar connecting the main hoops. First link goes straight to the cage pictures, second link is the entire thread.

http://www.gt40s.com/forum/209168-post162.html

http://www.gt40s.com/forum/gt40-build-logs/18681-build-diary-rcr-lola-t70-spider.html

I know that doesn't exactly fit with a GT40 but cage info is not all that common since not that many folks do them at all, and very few do them to any class specifications.

Ron

 

[Howard Jones]

Re: roll cage pictures please

Yes I have a 5lb bottle behind the drivers seat. I am 5' 2" tall and I have plenty of room for it there. If I was to mount it anywhere else I would put it right up against the front of the passengers seat below the knees so to speak. Two reasons for this. first the gauge can be read easily and second the bottle will survive the same impact that the passengers do. This would not be true in most cases if mounted up front behind the radiator for example.

I have one nozzle pointed at the fuel pumps and the other pointed at my chest from under the dashboard. The idea here is to fill the engine room with halon and the drivers compartment at the same time. A 5Lb system will really fill the small space we are talking about in a GT40. The engine room being pretty much contained is very small in volume and the drivers compartment couldn't be any smaller and be a two seater.

The cage in my car is like most others I've seen in a GT40. Two hoops one behind the seats up against the bulkhead and tied into the existing structure. The other follows the windshield and is bolted into a welded in plate triangulated in the corner of the chassis tubing that forms the corner of the interior. They are connected with two pieces of tubing running down the center-line. This is the minimum sort of standard road/trackday type of cage in my opinion. Mine is made form 4130 and I have forgotten the wall thickness but I think it is 1.5" od.

I don't have any pictures of it with the spider off the car and it doesn't come out very well in pictures because it is black in a black interior. Sorry.

 

[Randy]

Re: roll cage pictures please

Howard, thanks and I look forward to seeing you and your cage at Thunderhill Jan 4. I Guess you could say I am a LITTLE excited, First time out for the car !!!
Randy

 

[Ross Nicol]

Re: roll cage pictures please

Yes I agree with Howard, with the spider fitted it's hard to see the outline of the cage against the black interior.
Ross

 

[Mike Pass]

Re: roll cage pictures please

Here are a couple of pics of the roll cage on a Southern GT. This cage has been passed by the MSA for hillclimbs and sprints. It also adds quite a lot to the chassis stiffness. As regards the need for roll over protection I would say that it it is well worthwhile. It all depends on the value you place on your your wellbeing and your life! Having seen a car launched 20 feet into the air and ensuing bad landing I know which way I vote. As regards the fraction of a second a lap due to weight saving versus going home in one piece you must be the judge of that. But I would guess anyway that the the better handling from a stiffer chassis will more than offset any weight penalty. If you use the MSA mandated high quality seamless or chrome moly tubing the cage doesn't weigh very much anyway. The cage should be properly welded in with the correct spreader plates as per the MSA "Blue Book" to ensure that it does not fail when "tested". I will post some pics of a cage currently being fitted to a GTD when it is finished.
Cheers
Mike

 

[Dean Lampe]

Re: roll cage pictures please

Here is my fire bottle. My nozzles point at the engine, left and right and at my chest.

 

[Randy V]

Re: roll cage pictures please

Having built a number of cages / cars certified by the SCCA, I think the only one cage that I've seen on this site to date that would pass the stringent certification process is that of Ron's.. Ian's RF117 is very close and from what I can tell only one tube short of being a contender. I've not seen all of Ross' cage so no comment.

Despite the obvious lack of side impact protection (which is required for all wheel to wheel competition cars) - there's also the lack of shoulder height lateral support bars on many of these cars as well as lateral support bars at or just below the dashboard. These lateral support bars *must* be made of the same alloy, dimensional material as the main hoop and the A-Pillar support tubes. All tubing must be DOM tubing with absolutely no ERW tubing. Not certain why the requirement for DOM as no one on the SCCA Comp Board not myself have ever seen ERW fail as a result of the way it was made (welded).

Randy - For most "track day" use, your car would not "require" any cage. However - you've recognized the obvious need for self preservation and want to construct something that would likely do the job in the event of an incident.
I like the execution of the cage in the cockpit area of Dean Lampe's car and think that it is sufficient for track day use. I like the idea of the removeable upper bars over the door opening to keep the front and rear hoops in check.
I have some other concerns on some of the cages I've seen here but they are mine alone at this point so I will reserve comment.

 

[MReid]

Re: roll cage pictures please

Here are some pictures of mine as supplied by Fran.

Rear diagonal (the plate next to it bolts on the other side of the aluminum chassis to reinforce the mount.

The other end of the diagonal bolts through the firewall and connects through this flange to the main hoop.

This is probably the best shot I can give you with the spider installed.

Here is where the main hoop bolts to the chassis.

And this is where the a-pillar down bar bolts to the chassis (I pulled the dash back to expose the mounting plate).

 

[Randy V]

Re: roll cage pictures please

Those are excellent pictures Dean & Mark...

Dean - you need to post more pics of the front suspension mods you've made... (on another thread of course - maybe your Build thread?)

 

[Fran Hall RCR]

Re: roll cage pictures please

Polished chassis too..flash bugger!!!

Bigfoot

Dean has not made any suspension mods...all stock arms and locations etc....


But I know he added a rod end bump kit to this steering rack...as noted in previous posts....so he can fine tune the car to his liking..

 

[Russ Noble]

Re: roll cage pictures please

I have some other concerns on some of the cages I've seen here but they are mine alone at this point so I will reserve comment.

Randy,

My cage has been built to the regs that I must comply with and I am happy with it. But if you perceive a weakness in my cage design/execution or anyone elses, I think you should mention it.

If only, so that anyone searching this forum as a guide to cage construction particularly WRT to a road car, will consider the points you have raised, rather than blindly copying a feature they have seen that you may think undesirable.

A road car cage would not be subject to any inspection but road cars have the potential to be involved in much more horrific accidents than on the track, bearing in mind the presence of 50 ton trucks, huge drops off the side of the road etc.

To my mind, driving on the road is much more dangerous than driving on the track.

Also this is a tech forum and no-one should be averse to discussing or raising any such issues that concern them.

Cheers

 

[Iain]

Re: roll cage pictures please

Randy,

A couple of pictures as requested, I have found that the intrusion bars do not really pose a problem for getting in and out of the car. I would love to hear from Russ on how easy it is to get in / out with the top bars in place. I would definatley add them if it is still possible to make a "timeley" exit if circumstances require ! It is obviously a real weak point in our cars but I guess thats the risk we all take

Iain

 

[Randy]

Re: roll cage pictures please

thanks for all the great input guys!!
Iain, that is a cage!!! Nice work!
Dean , Love the polished chassis
Randy

 

[Gary Kadrmas]

Re: roll cage pictures please

Hey guys,

Those brakes on the back of Iains car are pretty nice units too!

 

[David Briggs]

Re: roll cage pictures please

Randy, are you going to the Western States Cobra Bash in May?
And Russ you mentioned seeing my car with a broken suspension, it was actually the upright that failed and now I have upgraded all four corners with Ian's steel uprights and different stub axles, axles and off road CV joints.
Those parts won't fail again.
I probably won't have it on the track again until May but will have a report then.
Dave

 

[Mike Drew]

Re: roll cage pictures please

FWIW, most original GT40s raced without roll cages as they weren't required back in the day. After Walt Hangsen was killed at the Le Mans test days in April 1966, and then Ken Miles died testing the J-car at Riverside in August, Ford got on a big safety kick, and actually crash-tested a GT40 Mk II. That car was fitted with a prototype roll cage, and roll cages became standard equipment in all Ford-entered (Shelby and Holman-Moody) cars for the 1967 season.

Fortunately, the individual who built the roll cages for the Holman-Moody cars is still around, and is still building GT40 roll cages. Mike Trusty had one installed by Dennis Olthoff when Dennis was screwing his new Superformance Mk II together.

Whether an original-spec cage would satisfy current regulations, I don't know. But at least you could be assured that it was a historically accurate design....