Belly tank rear suspention

Hey,

Ok here is my question, does any one have any ideas on how to setup a rear suspention on a belly tank? Now some may ask why the heck I would ever want to do this, and the reason is simple...Location. I am in the process of building a lakester (Hellcat tank, V4F GL cl***). The main purpose of the tank will be a Bonneville car, but since I live on the East coast I thought it might be nice to run it every now and again at Maxton or that new place in Maine. From what I am told these places require rear suspention, where as Bonneville doesnt.

I have set up rear suspention many times before for all sorts of cars, but this is much different. There is basicaly no drive shaft (2-3in max). I was thinking maybe making it so the entire motor and trans moved with the arc of the rear. But after thinking it over it would just be way to complicated. Does anyone have any pics of belly tank rear suspention? Any kind of imput would surly help out.

Mike

 

You could do some kind of independent setup.

 

An independent setup would work.....But i really want to keep it as traditional as I can. My plan was to use a Halibrand 301 champ case with early ford tubes.

 

Not belly tanks, but the same setup. Looks like it's been done several ways.

 

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Wouldn't that setup with the motor mounted to the wishbone make the complete drive line unsprung weight? That cant be good.

 

Probably not all that critical in LSR, did 160 with a flatty after all.

 

fordat31: I too live on the east coast and in the process of planning a P-38 tank XO/GL build. Most tanks back in the day did not have rear suspension as you already know.

Just a question: I don't know why Maxton would require rear suspension and Bonneville would not.... My thinking would be Maxton would be alot smoother and therefore; would not require rear suspension as compared to the rough salt at Bonneville. But hey, I very well may be missing something?

 

Any reason you can't run a transverse leaf and split bones? I know it puts suspension elements outside the body envelope, but it is going to be hard to get a functional suspension system that fits inside that tiny tail.

 

I can see you have never been to Maxton if you think it is smooth. Built of cement in the early forties. Has deteriated a lot . I saw a solid axel modified roadster bounce 4" in the air in the pits. Driver said he couldn't go faster than 150MPH.

 

Yes Maxton is much rougher than the salt. I attended an even in Oct. just to check it out. There was a huge bump about 100 feet after the start line that would launch any car with out suspention. Also the Split bones and transverse spring would work if the drive shaft were longer. But since it is so short as soon as the rear moved the tini shaft would bind.

 

Er, good point. No chance of some kind of sliding coupler of any kind in there? What trans are you running? It wont need much travel. With the bodywork limiting the overall movement of the rear suspension to just a few inches, and with nice long bones the slider could be really, really short.

Even on my long travel (18" swing) 4x4 stuff, with nice long links, the slider travel is remarkably short.

 

Many years ago I saw some pictures of a swing axle set up made out of a V8 QC center with stub bells. The swing axles mounted to the bells with torque tube balls and clam shells. I don't recall who did it. A big name I think. Don Francisco?

Formula Ford style IRS suspension with a Hewland VW case transaxle is an option. But I have never seen a lakes/LSR car running one. The Hewland gear sets are easy to change in the field and come in various ratios.

A Corvair transaxle is also a possibility. But the gear ratios are limited. Would work with a De Dion rear axle.

 

I think that if you set the car up to have a driveshaft as long as possible and limited the suspension travel to 1 1/2" you might get away with using a quarter eliptic spring suspention. The quarter eliptic would lend itself to the tight confines of the belly tank.

 

Most of my suspention setup experience is with 4X4 stuff as well and I agree that the slide coupling only moves a very short distance. Do you think that would still work if the rear shaft only have one U-joint?

 

IMO- A IRS with parallel T-bars would be the most practical/aero.

http://www.1speedway.com/irs_quickchange.htm

 

Myself personally, I'd mount the QC to the trans, run a pivot point off of a midplate on the motor and very soft mount points off the front of the motor (maybe just a pair of curved pins mounted to the frame and hoops mounted to the block to help locate the motor as it moves through its arc), and then mount a pair of torsion bars inside of the tank and a rubber snubber to limit travel...if you mounted the pivot points on rubber bushings they would allow for very minor articulation of each tire, while the pivot and torsion bar setup would give you suspension...I would also do the wishbone system by mounting the drivetrain on the wishbone with torsion bars and a panhard bar you can keep much of it inboard on the tank...just be sure to use some sort of limiting devices so you don't wind up with too much travel...

 

Nope, there would have to be two, and it sounds like you wont have the room.

I suspect that an IRS setup might be the answer, or the entire drive train on a swingarm design, which might use fewer high-dollar parts.

Pivoting at the mid-mount like Ruiner says seems like it would allow for the movement to take up the smallest envelope. And you could run a couple of coil overs in front of the engine, getting pushed down. That would keep the springs out of the tight tail, and eliminate any need for the frame to continue past the pivot point.

 

My roadster was very much inspired by the Markly Bros. Tank which was very much inspired by Bob Herdas 'liner. Mine has a V8 QC hard mounted with Ford torque tube bells just outboard of the side plates. And a spool. Splined to accept Linclon U joints.The outer axle tubes are '56 Olds as are the backing plates and brakes. The axles are shortened and splined to the Lincoln u joints. Morris cross toursion bars and some shocks that fit at 45 degrees. I could remove the deck lid and take pictures if you need it. but that is a Very tradtional tank rear end.

 

I love the coilover setup idea, much less weight, space and work than a torsion setup and just as adjustable...hell, it doesn't even need to be a ball mount wishbone, you could easily get by with an A-frame custom fabbed setup located at the front by a pair of urethane 4 bar bushings...or run quarter elliptic frame mounted springs inboard on a single trailing arm, and the trailing arm mount pivots like those swivel shackles (only a much stronger, handmade version) with your drivetrain mounted to the trailing arm, and again the engine, trans and QC are all one unit, the quarter elliptics and panhard will give you your locating, the swivel mount gives you your articulation...

 

Man. 100 was fast in the Peter Beater. Holy ****.

 

Man, I'd be very surprised if nobody has done a single trailing arm on a bellytank...swivel mount from ch***is to trailing arm, front motor solid mounts, lower midplate mount and a trans mount, then some tabs and brackets from the QC bell pattern holes to the trailing arm...you could do torsion bars perpendicular to the axle tubes coming out of the tanker, or an inboard quarter elliptic setup from the ch***is angled to the trailing arm by the QC, or a pair of coilovers in the same way the quarter eliptics mount along with a panhard/track bar for any of those setups...just gotta make sure your swivel mount has limited movement and use ch***is straps or snubbers to limit your travel...someone has to have already run that system, right?

 

In the early 50's there were several streamliners and modified roadsters built with the complete engine, trans, and rear mounted on a fabricated wishbone. At the front of this wishbone was a Ford pivot ball. This was mounted in a female socket located in a crossmember. At the back end the whole ***embly was mounted to a buggy spring in the conventional way of all Fords.
This allowed for a sprung rear end without any driveshaft to bind or bottom out.
There are some photos in early 50's Hot Rod magazines showing the whole ***embly sitting out of the car.
PM me if you don't have access to early Hot Rods and I'll dig through my collectoin and post them.

 

I would probably use the diff centre and inboard brakes from a jag IRS. That could pretty much mount direct onto the back of the gearbox with a simple chain coupler.

A pair of swing axles and split rear bones would locate the wheel hubs, add a pair of motorcycle coil shocks, and that is about as simple as it gets.

Minimum unsprung weight is what you need for best road holding at speed on a bad surface.

 

Or.......... you can go to post #4 and open the pic and look to the right of and just below the top staple

 

Now that I've thought about it, in a perfect world it may be all well and good. But I have to wonder what would happen if a tire blew at speed and all that weight was flapping up and down

 

The Beatty tank also had a rear swing axle made with torque tube parts.

 

Especially With inboard brakes, it is the simplest, cleanest, and lightest solution.

 

Ok there are some great ideas here. I have drawn up a little sketch of a suspention that I think might work. When I go into work tomorrow I will scan it in and post it.