Projects DRAG SNAKE "Vintage Terror!"

I saw this in Tulsa, wasn't sure if this was the same color or not?




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Some issues that I see looking at the photos of the rolling chassis. First there is no need for the diagonal locator from the front ladder bar mount if you plan to run the Watts link.
The spring base at the rear is very narrow and if the shocks are mounted in the area of the shackles the same will apply to the amount of damping that they will supply when the chassis rolls laterally. There is plenty of room to move both out so that they are closer to the inside of the tire. In that case the spring perch could be mounted to the frame outrigger structure that I presume (and hope) that you are planning to add to provide some measure of protection in the event of a side impact. I know that an original Cobra did not have much out there apart from the cowl hoop but you are going to need something to mount a cage to.
As the torque arm/ladder bar is going to be carrying all of the torque loading I would also like to see the bracket beefed up somewhat. I understand that the bracket was made to utilize the store bought ladder bar but I think that a better solution would have been a custom ladder bar that mounted directly to the housing and still allowed removal of the third member.
The 90 degree kick ups in the frame are also not ideal strength wise. With a lesser angle there is more room to effectively spread the load along the tubing surface with diamond shaped gusset plates on either side.

Roo

 

I'm not getting the shackles on the 1/4 elliptical springs.
Usually a 4 bar or ladders with shackles on 1/4 elliptical springs. The springs are just springs.
Or
There are no shackles and then 2 links while. The springs are the second pair of the 4 links

If the shackles weren't there, that would be 2 links in the springs, and the torque arm would be the final part in a 3 link set up.

Interested in learning something here

 

The torque arm is going to make the axle move in a very shallow arc and the springs are much shorter so even with limited travel there will be some binding without the shackles as the torque arm will not let the housing rotate to compensate for the differing arcs. In this case the torque arm is the ladder bar in your first example above.

Roo

 

Thanks Roo. Yep you have to be careful of intersecting travel arcs because at that point, the suspension locks and leaves a bunch of horsepower and torque no other option than to bounce the rear like a Mexican jumping bean. I have had a bit of experience with that you know...LMAO!

 

I took some measurements last night and I would have room in the drive shaft tunnel for both of the ladder bars. Basically mounted together at all points. That might be over kill because we are not going to make a 1000 pounds of torque back there but I have the room and I have the ladder bar.....

Also as you can see below, we have some strengthening measures for the rear mount bracket after we decide the center section is in for the final time etc. We have six bushings cut to size; we will drill holes through both plates, run a grade 8 bolt through and then tightened the plates down on the bushings etc.

 

You need to look at how others have set up a 3 link like that. even the early fords had more to hold the axle square with the frame than that.

 

Now I'm not the guy who walks into the kitchen while dinner is getting prepared and asks "why the place is a mess" ,,

I caught the mention of the watts link, (controls the rear end center)

And also I caught the addition of another bar off the torque arm,,,
On the other side of the drive shaft (stop the Yaw on the shop floor as stated)

So that skinny triangle formed by the next bar and the torque arm is going to be enough to keep the rear end squared and wheelbase equal under hard launch and high horsepower with possible uneven traction?

Or is there another part I'm missing ?

Like maybe link bars above the springs?

 

31vicky,
you are totally correct in that there is not enough location for the rear axle as it currently stands but as I noted the shackles are necessary to stop the springs from binding up as Deuced Up has already found out with the Austin.
The diagonal bar as shown in post #684 would help a little but as you note the spread between it and the ladder bar/torque arm is a little too narrow for it to be really effective. The Watts linkage will stop the rear end from moving side to side but right now the problem is that there is too much chance of substantial front to rear motion at the outer end of the housing and I don't think that rear wheel steering is a good idea on a drag car.

Roo

 

Is there something in the way ? To run one on the other side.

 

Because of the seating area etc. on the Cobra the chassis is practically an under slung design (meaning the floor pan is going to set directly on the dropped frame area there). We are sneaking the ladder bar into the drive shaft tunnel so it does not effect the seat placement etc. The original plan as shown a few pages back was to actually put one on either side of the drive shaft but the mounting area on the driver's side of the shaft was very limited because of the third members offset etc. If we were to put a second one closer to the frame rail there, the driver would basically have to saddle up on it to drive...LOL.

 

Here's an idea:
Place a jointed bar on each side, outside of the frame rail, maybe right above the springs. Maybe right next to the springs. This will solve fore-aft problems with your rear tires. Then you will need to place a shackle at the front of the torque arm to allow for the different arcs of the long arm and the shorter bars. I'm pretty sure I've seen this setup somewhere else before.

 

I know it's like stuffing 10lbsof stuff into a 5 lb bag.
It just seems there should be controlling link bars where your springs shackles are.

 

Playing with paper dolls today. LOL ......but I think I have a fairly cool answer to the "yaw" issue. We have such limited space back there but I think a couple of brackets on the top of the axle tubes that hold a watt's link (one on either end) will keep the axle right where we want it front to back etc. and not create any crazy cross arcing suspension movements. In someways it is a little like a birdcage from the Sprint car world. AND if I had been thinking further ahead, that would have been a very cool way to have done this rear end from the beginning but such is life. Anyway just to sort of test it on paper this is what if found....

 

I thought u wanted watts for side to side not fore & aft. They doing same job as link arm. Disconnect in video and move link arm same result. What controls side movement of rear? Sorry if I miss your plan.

 

Here's a pic of the torque arm with a shackle on the front. Then you only need to run two short-ish links at the outboard ends of your axle. Out somewhere between the tires and the frame rails. I'm sure lots of guys could tell you the proper height and angle to promote squatting properly for the racing grip. Keep your Watts links running sideways.

 

Look into maximum Motorsport torque arm system for 79-04 mustang. You would make a shorter version that uses your trans cross member as a mount. The outer control arms would be like the blue arms in earlier picture. These setups have carried the frt wheels on heavier cars than yours with a lot more hp. The watts link could be swapped for a simple track bar. Can't wait to see it humiliating some vettes !!!!!!!!!

 

Alchemy , you read my mind.

 

Looks like that Watts link is just along for the ride and not accomplishing anything that the torque arm isn't already doing. It did look like a fun art project though.

 

In this case the Watts linkage is located at the outer ends of the axle housing (on each side) to control the "yaw" that came with the torque arm and the spring shackles as the only longitudinal locating points.

Roo

 

Watts at each end of axle to prevent yaw makes sense now. What controls side to side movement?

 

Another Watts Link. I call it the Quarter Elliptic Torque Arm Tri-Watts Suspension.

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Thats some funny stuff right there......

 

It is basically what I call all the reinventing the wheel garbage that as usual I will likely toss after bit and replace with a four link and coilovers. LMAO

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That might work
I mean that 4 link and coil overs idea

 

It is looking like a lot of parts.

 

I really like the shackle idea up front like @alchemy showed. The guys at SW Racing have one too (similar to that) and I actually spoke with their engineer yesterday. My concern was that shackle is going to take a crazy hard hit at launch. He said no issue and is sending me some specs and an idea how to build my own shackle with the arm I already have in place. That would be really nice and simple (as someone noted earlier) we could just install the shackle and a couple of shorter control arms out back etc. I will keep you updated.

The goal either way is to get the wheel wells trimmed and cleaned up (front and back so we can finally set the body on. This will answer a lot of our space needs questions and it is goofy to go much further with out knowing for sure.

 

Lower arm on each side just outside of the frame, make your front ladder bar bracket float front to rear... Like a floating shackle that the dirt guys use. That would eliminate binding and keep the outer axle tubes in check.

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Could you go with triangulated control arms from the top of your rear to your frame uprights? (like a Chevelle rear) No Shackles on the springs and shackle on the ladder bar?
I really know little about suspension geometry. Just a thought.