Cage Design

How does this look for a cage layout?


Angle


Front


Side

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Welcome to the cult of JVL drink the koolaid or be banned.

Looks pretty standard.
I'd include a transverse bar across the botton of the main hoop and top corner windshield gussets... but I don't issue log-books :-)

-Martin

I'm also a big fan of the double door bar X with 2 continuous bars instead of 1 bar and 1, 2 piece.

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"Time to unpimp ze auuto."





sleightc (A.T.) Yahoo {DOT} com

Since you are now required to have a main hoop X, we've gone with roof bars as seen in 253-14, with rear bars like 253-22. It's less welds and you can bend the roof bars to get them closer to the contour of the car and further from your head.

> I'm also a big fan of the double door bar X with 2 continuous bars instead of
> 1 bar and 1, 2 piece.

I'm a big non-fan of this. The accident that has encouraged this to be recommended by some safety stewards was fatal regardless of the failure of the door bar from what I have heard. The arguments go back and forth on specialstage so I'm not going to start another here.

Remember you can bend the a-pillar reinforcement to bring it along the contour of the door and that it can be two piece. It just must remain straight in side view looking perpendicular into the door.

I also agree with what Martin said, put a transverse bar across the bottom of the main hoop, like in 253-30. Weld it to the tunnel as well.

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Grant Hughes

if this is for your corolla, the brace for the upper shock mounts is not needed.
skip the v-thing and the tie bar.

you will also find the roof profile of the sheet metal is more complicated

you want to service for me this weekend?
pm me.

adam

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"I put the hurt on dirt" - adam crane
http://CraneRallyCrew.com
corolla gt-s "Patches"
Op: S.S.

NoCoast Wrote:
>
> > I'm also a big fan of the double door bar X
> with 2 continuous bars instead of
> > 1 bar and 1, 2 piece.
>
> I'm a big non-fan of this. The accident that has
> encouraged this to be recommended by some safety
> stewards was fatal regardless of the failure of
> the door bar from what I have heard. The
> arguments go back and forth on specialstage so I'm
> not going to start another here.
>
> Grant Hughes
> www.nocoastmotorsports.net
> Denver, CO


I'm not familiar with the accident you're referring to. Nor have I read the arguments. I guess I should touch up on that. The accident that lead me to be a fan of this design was not fatal though I believe it could have been with a different design.

I'm not all that versed in cage design so don't take anything I say to be worth anything, but when I design a cage from scratch, it'll have that style door bar in it, unless I see something between now and then to change my mind.

---

"Time to unpimp ze auuto."





sleightc (A.T.) Yahoo {DOT} com

Ok, here is the new design, and it's even to scale.... (yes, I really do have THAT much time on my hands)



I ommited the bottom main hoop transverse backwards forwards left right up down bar thats welded to the tunnel because while I was talking to JVL, he mentioned that due to the X in the main hoop, that bar would have been redundant. If I have some extra tubes, and willpower, and caffiene left running through me... maybe I'll add it.

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Welcome to the cult of JVL drink the koolaid or be banned.

Oh, it is redundant. I like it because when I think of if I hit something square on that side that it now has to move and cause deformation in lots of places, including the tunnel. It's not too much weight and it's not a huge deal if you don't use it.

Oh, and those photos look cool. Now you need to add in all the gussets.

Freeman/Lovell. The door bar welds broke and impaled leg. Had internal injuries not been a cause of death, loss of blood from that injury may have. But, there were other injuries that were much more serious.
Now I have to say that is a little bit of conjecture there. I first started hearing about the liking of bent door bars from our local safety steward, and the reasoning (in an accident somewhere a door bar broke and impaled the leg, severing the femoral artery) shortly following their accident (about 3 months). Later heard that the door bar had broken on their car and had happened as described. I don't recall hearing or seeing this design prior to that accident.

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Grant Hughes

Sprongl's had that new design (2 bars w/ bends welded in middle) in their Evo that wrecked at STPR two years back... After the fact, Frank and Dan both commented on how much safer they felt having the cage built like that... tubes bent, stretched, pulled in other members... rather than breaking at the welds and impaling Dan.

Oh wow. thats not good. Do you know anything about the crash? What actually happened?

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Welcome to the cult of JVL drink the koolaid or be banned.

Ok.. heres my 7 cents.

the latest design is very good. And allows for the most head room and like that.

However..if it was me... i'd make a few slight mods to some of these bars to get them to fit better, and to allow you more headroom in the car, along with better entrance/exit from the car.

The "top of the windshield bar" bend this bar about 6-8" in from where it meets with the lateral bars, so this bar comes back a little bit. Now...you add 2 little 6-8" pieces of tube which form a triangle to the main hoop, in the windshield opening. These little pieces of tube serve as your mandatory gusset here.

Now..because you have put these bends in there...Move the "roof-v bars" in to the crotch of this bend, and you do gain a bunch of head room

Now..When you put in your "a-pillar support bars", run them to where your "windshield gusset bars" join to the lateral bars. Gives you more room to get in and out of the car. Also, you then form a nice line from the bottom mounting foot, up through this bar, through your gusset bar, and to the roof v bars.

The "main hoop to lateral gussets" (ones beside your head) I like to run these further down to the joint of the top door bar....if possible in your car.

The "door bars" from my personal experience. it is MUCH easier to get into and out of the car if you make the juntion of the 2 bars in the center of your entrance/exit path, than it is to have it directly centered in the door. In my experience this is about at the front of your seat. Also....do not be affraid to move the top door bar joint at the main hoop up. I like to have it about where the bend is for the main hoop. Obviously the height of the door bars at the main hoop vs the a-pillar can be drastically different.

You can see what i'm suggesting in the quick paint sketch.

Another thing you are going to want to consider. 2008 and Rally America wants everyone wearing a HANS (or equivalent). Because of this. you need to give more thought to belt mounting. I can tell you that ALL belt manufacturers STRONGLY recommond the shoulder belts be mounted no more than 8" behind the seat. Plus i can tell you that if you order the soo popular G-force 5 point FIA approved belts...in most cars the shoulder belts will not reach back between the strut towers.

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Chris

Which part of your picture is the continuous windshield bar? Is the gusset to the front half lateral bar on the windshield side or the back? By the way, that's not required to be gussetted anymore.

I agree with you on the door bars to support being near the main hoop. There are technically some limitations on the dimensions of that though so be aware.

Also, the a-pillar reinforcement has to be within 100 mm of the junction of the windshield bar and the front half lateral. That means you can go about 4 inches forward with it to give more space for in/out. It also makes it into a fucking cruel angle to profile. Thankfully, it's 1.5 onto 1.75 so that helps keep the gaps down.

We've used the same design now in a Merkur, Legacy, and Impreza and all three are comfortable, easy in and out, and two of the three passed tech and logbook easily.

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Grant Hughes

Let me suggest that you decide on the final roof (and backstay) brace configuration only AFTER you have the main structure of the cage built AND have done a preliminary fitting of the seat within the main framework. The reason is that due to difference in people heights and prefered driving postion and sterring wheel and pedal locations, the end location of you head relative to the roof brace bars can vary quite a bit. For example, for a Ford Focus and a short person sitting closer to the wheel, the X configuration can be better, with the roof bars not over your head.

If this is being done by a shop, then make sure you present both the x- and v- brace options upfront, and explain that you need to work with them to locate the seat and make the final brace config decision during the build process.

Also, where is the plane of the main hoop located relative to the plane of the car's B-pillar? The reason to ask is that if you place the main hoop well behind the B-pillar (as is being done more and more) then the upper diagonal brace in the door opening becomes more important, to provide more protection from the B-pillar being crushed in upon your upper torso/shoulder. The longer brace as drawn by Chris illustrates this.

Looks very good overall; this should be an excellent cage in any of the cofigs you have drawn.

Regards,
Mark B.

dtompsett Wrote:
-------------------------------------------------------
> Sprongl's had that new design (2 bars w/ bends
> welded in middle) in their Evo that wrecked at
> STPR two years back... After the fact, Frank and
> Dan both commented on how much safer they felt
> having the cage built like that... tubes bent,
> stretched, pulled in other members... rather than
> breaking at the welds and impaling Dan.


The Sprongl's accident is the one I was originally referring to. I saw pictures of the door bars folded inwards after the accident without breaking and was pretty impressed.

---

"Time to unpimp ze auuto."





sleightc (A.T.) Yahoo {DOT} com

Do It Sidewayz Wrote:
-------------------------------------------------------
> Ok.. heres my 7 cents.
>
> the latest design is very good. And allows for the
> most head room and like that.
>
> However..if it was me... i'd make a few slight
> mods to some of these bars to get them to fit
> better, and to allow you more headroom in the car,
> along with better entrance/exit from the car.
>
> The "top of the windshield bar" bend this bar
> about 6-8" in from where it meets with the lateral
> bars, so this bar comes back a little bit.
> Now...you add 2 little 6-8" pieces of tube which
> form a triangle to the main hoop, in the
> windshield opening. These little pieces of tube
> serve as your mandatory gusset here.
>
> Now..because you have put these bends in
> there...Move the "roof-v bars" in to the crotch of
> this bend, and you do gain a bunch of head room
>
> Now..When you put in your "a-pillar support bars",
> run them to where your "windshield gusset bars"
> join to the lateral bars. Gives you more room to
> get in and out of the car. Also, you then form a
> nice line from the bottom mounting foot, up
> through this bar, through your gusset bar, and to
> the roof v bars.
>
> The "main hoop to lateral gussets" (ones beside
> your head) I like to run these further down to
> the joint of the top door bar....if possible in
> your car.
>
> The "door bars" from my personal experience. it
> is MUCH easier to get into and out of the car if
> you make the juntion of the 2 bars in the center
> of your entrance/exit path, than it is to have it
> directly centered in the door. In my experience
> this is about at the front of your seat.
> Also....do not be affraid to move the top door bar
> joint at the main hoop up. I like to have it
> about where the bend is for the main hoop.
> Obviously the height of the door bars at the main
> hoop vs the a-pillar can be drastically
> different.
>
> You can see what i'm suggesting in the quick paint
> sketch.
>
> Another thing you are going to want to consider.
> 2008 and Rally America wants everyone wearing a
> HANS (or equivalent). Because of this. you need
> to give more thought to belt mounting. I can tell
> you that ALL belt manufacturers STRONGLY recommond
> the shoulder belts be mounted no more than 8"
> behind the seat. Plus i can tell you that if you
> order the soo popular G-force 5 point FIA approved
> belts...in most cars the shoulder belts will not
> reach back between the strut towers.
>
>
>
> Chris


Oh yeah?

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 10/08/2007 02:34AM by john vanlandingham.