Will a a trailing link kill you?

[Jonesy]

Thought this was a bit silly to post in the suspension handling section.
I unfortunately have come across some nasty accidents and been first on scene. Had to hand around and help the unconscious occupants while the car was cut away. I noticed how the interior and reinforcing bars twist and snap and so forth.

Anyhow i was looking at some RCR and RF's chassis pics and noticed the lower trailing link and upper trailing link location.
In a rear end collision or rear qtr, what is the likeliness of these sheering of and protruding into the cabin?
I honestly have not seen them up close but they look very close to your bum and back/spine?

No flaming just a question guys.
jonesy

 

[Malcolm]

This would actually apply to most if not all GT40's both replica or original as trailing arms are the standard way to go. I would suggest other factors will kill you first, namely the engine and box punching through the rear bulkhead. If you consider the energy path that needs to hold up to spike a trailing arm through, it is more likley that the sizeable collision required will transmit more direct energy via the drive train than the suspension arms which would break up at various joints disappating the energy on the way. Just please don't ask me to test this theory out......

 

[roaldin]

Re: Will a trailing link kill you?

I haven't seen my car for a while so I'll be happy to stand corrected, but from memory:
in the RF, the "seat" end uses a bolt that is supported on both ends (and also sits in a "cup" that would hopefully help retain it), whereas the "wheel" end has a rose joint retained on a bolt supported on only one end and should therefore break more easily. Hopefully this would mean that the "seat" end would stay attached. Accidents are pretty complicated things though so I hope no-one ever finds out if I'm wrong...

I thought about this when I first investigated the RF.

I haven't seen the RCR.

Tim.

 

[Paul Thompson 'Hooligan']

Hi Jonesy

I've seen a few damaged 40s and have never seen intrusion into the cabin of a rear trailing link. There are a lot of other items/material about that would absorb energy before a link mount broke or detached I would think.

Also, in the event of the sort of impact required to actually cause links to detach and penetrate, I would think that that possibility would likely be the least of your problems.

The question of whether a trailing link could kill you I guess will be yes - but you'd need to be mighty unlucky...

Just an observation and not based on any technical analysis or calculation...

 

[Fran Hall RCR]

I have looked at this in the past also.

Its one of the reasons that we use a 3mm thick aluminum firewall and not a thin applique or fiberglass one.
The RCR seats are also 3mm ali. so for a link to spear a driver it would have to have a pretty direct impact to penetrate 6mm of aluminum with no deflection....not impossible but neither is stepping off the kerb and being hit by a bus...

The lower link would have to make it through 9mm of ali. to do any harm...

Good observation though...

 

[Jonesy]

I'm glad more than one person has thought of this, i felt a bit stupid asking it. Im sure if it had happened someone would have known and we would have herd as all the GT40's ive seen have this set up.

Is there any replicas, factory cars or scratch built that use a double A-arm set up?

Has there been any dangerous episodes ever reported in GT40 replicas? ie fuel cell fires due to ruptures etc

A little off topic but as someone was mention energy released.... a previous partner of mines father works high up in the railways and is a rail enthusiast who has written and contributed photos to books. One of the books detailed Train crashes. We all know how strong those locomotives are and those old steam trains. Many parts made from solid thick steel. Well some of these crashes compressed the trains to like a quarter their size and bent things i though was unbend able! However when you look at the figures, possibly 14thousand tons of weight being pulled then do the math of how much energy is released on impact its quite imaginable, still quite a site to see a locomotive half its size and shaped like a boomerang!

 

[Fran Hall RCR]

Yep...the New Ford GT....

 

[TimB]

Here is your answer about fuel. This is an origional being crash tested....note all the liquid spray

 

[Brian Hamilton]

Here is your answer about fuel. This is an origional being crash tested....note all the liquid spray

That picture just made me cry...

 

[Russ Noble]

Is there any replicas, factory cars or scratch built that use a double A-arm set up?

This link has some photos of a modified GTD (I think) with push rod suspension and A-arms.

http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/15641-engine-orientation-40-a.html

 

[Jim Holden]

In the crash test of the orignal GT40 MKII most of the spray of "fuel" (actually a non flamable liquid for the test) was due to the "quick fill" caps failing and the force of the liquid shifting forward in the tanks due to the impact. That's why its a good idea to use "twist off" fill caps under the click open fill caps.

Jim

 

[Cliff Beer]

Basically, a GT40 replica (or real) is a very unsafe place to be in a major accident. No airbags, no engineered crumple zones, no bumpers or side impact bars, feet hanging out there, wimpy fiberglass spider, etc. I think I'd rather be "thrown clear" as the old joke goes....but, seriously in this case!

 

[Jonesy]

I suppose as dangerous as they are they are still safer than a club man (lotus 7) Also the lighter weight would allow the vehicle to move more in impact. I also guess a thicker wall tubing and side intrusion bars would be an improvement. Either way we don't build them because they have a 5 star rating.

This link has some photos of a modified GTD (I think) with push rod suspension and A-arms. http://www.gt40s.com/forum/gt40-tech-engines-induction-exhaust/15641-engine-orientation-40-a.html

Thanks Russ thats exactly what i was looking for. I am by no means a suspension guru, however i do have a copy of some of the books about chassis design i bought of Amazon that i really should read. I had hopped to use an a-arm design on the rear for two reasons. It seemed simpler to figure out good geometry and if push comes to shove one could incorporate possible the rear parts of a donor vehicle like the 300zx or toyota supra as mentioned by 'jac mac' in this thread:
http://www.gt40s.com/forum/gt40-build-logs/24313-good-bye-locost-7-hello-gt40-4.html
Would keep the Department of Transport a little happier as they are funny about touching suspension and steering.

I have always been a bog fan of the set up mentioned in that link where the engine, T/axle and suspension are a single item that bolt to the main body(is there a proper name for this). The UN-1 T-axle and suspension actually like quite neat and simple. Off course you would want to make sure its bolted nice and tight to the rest of the vehicle and the chassis is strong enough to support it all.

Anyhow, most gt40's if not nearly all use the Trailing Arm design. I assume this is due to space constraints and to allow easier removal of the engine and t/axle. To use Double A-arm im assuming you would nearly have to wrap the chassis around the engine then cut back in where the trans is to accommodate enough length in the A-arms themselves? Even then the forward section of the arms would be to short?
Educate me
Regards
jonesy

 

[Daryl Adams]

Here is your answer about fuel. This is an origional being crash tested....note all the liquid spray

Man, that is one sobering photo. I guess that's the main reason I will never run my GT40 hard at a place like Road America, and why I rarely carry passengers. Given their level of performance and the vulnerability of their fuel systems, these were dangerous cars when new and remain so. That shot almost makes me want to wear my nomex on every drive!

 

[Rick Muck- Mark IV]

Here is your answer about fuel. This is an origional being crash tested....note all the liquid spray

Keep in mind that this test done by Ford using Stoddard Solvent in lieu of fuel (same weight/density) was with the fuel bags and larger capacity than an SPF or most replicas. The fuel caps failed and as the bags went right to the front of the sponsons, there was intrusion right away. Most replicas have alloy tanks and they are smaller and set back some. Plus SPF, CAV and some others use a proper fuel cap under the Monza filler.

As to the trailing arm, it would need to be a "perfect storm" for the rod not to bend before the bolt in the rod end/bracket either tears off or fails. As they are on a multiple angle I think the impact would need to be "right on" for the force to travel in the plane(s) of the trailing rod.

 

[Pete McCluskey.]

That certainly is a scary photo. Mark1V, thanks for the info, I curse my "proper" screw on fuel caps and narrow fuel hose when filling up at the pumps.
I will now look upon them with affection.