Mike S.

Tinman...the intersection point for the X on the rear legs is typically in the rear field of view for caged 944's I've been in. To get one of those rear X diagonals to align with the main hoop diagonal usually is not possible if your pickup points on the rear legs and thus X are outboard, which is where you generally desire them to be. The result is just more diagonals in the rear field of view, which we know John is wishing to avoid. Given that this is what John judges as an advantage and is his design criteria/requirement, the merit (advantage) of his solution is more than the "cool factor of the way your drawings look".

Please jump in here with some details if you've got something that gets a main hoop diagonal and rear diagonal to "line up" as one looks in the rear view mirror. Shoot us a pic if possible.

Mike

tinman944

Mine line up on the same angle. When you look in the mirror I only see one bar.
One problem I see with John design is with the cross brace, It starts to far in towards the center of the car. the closer you put that towards the outside edge the lower it is in the sight of view.
On my cars I do not X I just use the one cross bar. one on the main hoop and one ons the back braces.
The second problem is the main hoop is not set back far enough for his seat location.I think the placement of the cross bar is inward so it clears his helmet or head .
Sorry no pictures that I want to show.

Funny thing is I think John and I got the saws-all out on the same day.

RedlineMan

Hmmm...

Since I am one who has previously been called on the carpet by some for having strong opinions, I should not by rights deny others their own.

I also know that there are many ways to accomplish something. I am looking for more creative and esthetically pleasing ways of accomplishing the goal. It is true that straight lines are strong when it comes to structures, but Hell... what would all the architects do for a living? It would be a damn boring world if only those that could draw a straight line were allowed to design anything. Truth be told, there is a lot of strength in virtually ANYTHING if it is done right.

For instance, if you look at my belt bar arrangement -vs- what Carrera is offering (please, do dabble away! ), if one were stronger than the other, I would not want to try and live on the difference between them. His certainly would be strong and simple. The difference as I see it is that how many would think of doing a belt bar the way I did -vs- simple pieces of angular tubing here and there? I prefer to look for unique solutions that offer visual interest yet give up nothing structurally. If those that have questions sit and study what would be pulling on what, from where, and in what direction, you should be able to see that mine is quite strong indeed. Camber, you can even see your triangle (or "A") if you look.

My main hoop is placed EXACTLY where I wanted it, and for some very good reasons.
- it is hidden
- it compliments the important existing structural member that is the b-pillar.
- it shortens the longest unsupported and most vulnerable piece of tubing in the cage; the side hoop. This vulnerable expanse will also be further supported by an angled tube from beltline-high on the main hoop to the side hoop next to my head (see avatar).
- because it IS very nearly over my head, it will better PROTECT my head from intrusion. In terms of roll protection, it does little good to support a part of the car where no one sits, or that does not usually fail in the first place. The further back you go, the more that is the case.
- it shortens the length of the door bar, making it stronger.

Considering the only part of this project that has ever been on paper is the rear truss idea, I think it is going well!

Comments are appreciated... mostly.

RedlineMan

Speaking of door bars...

Larry Herman

How are you going to get your big butt over that thing?


Don't take umbrage, you should have seen me trying to crawl into that cup car. Glad no one had a video camera.

RedlineMan

Oh Larry;

If you're no small fry trying to get in a Cuppy, imagine me? It is quite a procedure, you can trust me on that! Plus, the one I used to have to crawl in was driven by a guy 5'8" & 155lbs!

This setup is very similar to the 944T I did last year (avatar), except my bar is higher. It's actually a little harder to get out than in, but not bad in either event... really!

The REAL question it dawned on me to ask before welding it in was... can I get the SEAT in!

RedlineMan

This one started bugging me;

Where is there extra tubing? Aside from the sill tube, they are the quarter rounds that project my belt bar, and the two/per quarter rounds in the door bars. A good morning dump and a hair cut would drop that.

If I had the dimensions handy, I could calculate how much my proposed 1" .063" rear truss would weigh compared to the generic 1.75" .095" X, the former weighing only .630lbs/ft. (37.52% of the latter)

tinman944

OMFG

Mike S.

Tinman,

Thank for the insight.

Why not? Hope you change your mind. Inquiring minds what to learn.

John,

I know others have said similarly in the past, but I too like that side bar design for an NA 944. Functional and sharp looking.

Larry,

I would enjoy watching "big" John getting into a NASCAR door barred 944

Mike

tinman944

There is no function to that door bar at all. Yes it looks pretty with all that bondo on it...In a side impact It makes me wonder how long the doctor is going to scratch his head wondering if he should take all the Bondo chunks out or just cut off the leg.

Geo

Well, since you are asking......

I've seen a lot of cages that are at best less than efficienct (strength vs mass) and at worst, let's say "not so swift" because of builders being too clever.

A cage serves two purposes in a race car - safety and stiffening. Anybody can build a strong and stiff cage, but the trick is to do it while being efficient with materials (to keep mass low) and with as few bends as possible. I think we all agree (and I know that you and I do) that all cages involve compromise, or IOW, no cage is perfect.

I think the architect is not a good one because their mission is generally quite different from that of a cage builder.

For me, cage beauty lies in efficent strength. Also cage beauty for me lies in form following function.

FWIW I've critiqued my own cage in this forum, pointing out the compromises made and why. I guess I'm just saying that I know my own work is not without points to critique and critisize.

Oddjob

Ok, Ill ask:

By saying there is no function, you are implying that this door bar arrangement offers zero safety or structural improvement over having no cage/door bar in the car at all - is that what you are stating?

tinman944

The way the bar is right now in the car . If that car was to have a side impact in the door the driver would be in trouble.
There is nothing supporting that door bar from going inwards toward the driver.
Now think about what is going to happen when John puts that bar in up by his head.
Honestly I do not care what John does to his car..what I do care about is that no one follows in his footsteps when they try to build a cage in there own car.
There is more wrong with this cage then there is right,as far as safety goes. That is why there are rules and guide lines when you build a cage to meet the requirements of a race group.
Building a cage is a lot of fun . I would say most anyone can do it. A few simple rules to follow.
Do not try and reinvent the wheel.
There are plenty of guys on here that have built there own cages that look really good. and I would say are safe and stiff.

Mike S.

Tinman...adding to Jim's question, I was thinking you get some advantage like this:

tinman944

Maybe I am just going to sit back for a few days and see what John comes up with next.
When he is done I will give my advice.
I hate to help a guy out that already knows everything there is to know.
Lets do it like the tuners do. when you finish it up lets crash test it to see how safe it really is.
Mike I will Pm you later