Few, if any, of you probably remember a few years ago when I posted (better) pictures of my rear suspension when I first designed it. It is a triangulated 4 bar of sorts but the lower links are actually the quarter elliptic springs. Well, the car is finally getting almost done and I drove it a few days ago. I am pleased to say the rear suspension seems to behave very well on the first shake down. I did end up putting a little stiffer springs in after the dirst run but more because the back of the car sat about an inch low for my liking.
I did have but I can't seem to find them. Where the springs bolt in is actually the end of the 3x3 frame tube. I just made a plate with threaded holes and a hole for the center bolt. Then bolt up through the bottom of the frame to sandwich in the springs. The widest spring I can get in there is 1 3/4". It took a little snooping to find. I started out which cheap tractor supply trailer springs but when I decided to stretch the wheelbase a little they were too short so I used front leafs from a 47 Ford pickup. Then yesterday when I wanted it stiffer, I just changed out the other 2 leafs for ones from the back of a 39 International which are about .040 thicker each. Top links were made from a tie rod I pirated from a Massey combine. One thing that I can smile about now is how many people on this board told me it wouldn't work and only a couple members were positive. At that time nobody seemed to have seen it done. Even I wasn't sure it wouldn't wrap the springs and wheel hop. I haven't tried any hard launches yet but I did goose it hard coming out of a corner in second and kick the ass end out, let off the gas and it squared right up, no wheel hop or other negative behavior..
Actually looking at doing something a *little* like this, a pair of floating cantilever springs as lower links for a torque-arm setup with a Watts for lateral location.
Cool, I'm pretty sure that's the same style of rear suspension that Malcolm is running in his roadster that he's been running the wheels off of. There are pix on his thread if anyone is looking for more pix of this style of set up
http://www.jalopyjournal.com/forum/showthread.php?t=567286 if not in that thread click the link to the first half on the first page
A few years back I had a '32 3W that had a Dave Gale chassis under it with both rear and front quarter elliptical suspension. Unlike yours though, mine had straight top rods and a panhard bar. Of all the hot rods I have owned that one rode without a doubt the smoothest. I never had any issues "launching" it. Drove it for over 4 years without a hiccup.
How does yours drive out? I haven't had mine very far yet since I don't have a serial number yet. But so far I like it. I designed mine with the lower tabs as short as possible because I was worried about the spring wrap on acceleration and wheel hop. Very nice work btw, in a whole different league than mine.
Willowbilly3, have you had a chance to drive it more? That is how I'd like to set up the rear of my '26 Chevy roadster. I'm using the stock Chevy style front end.
So no shackles at the mounting points on the rear-end housing, right? Same basic idea as I am planning on, but the torque tube will serve as the third link. We discussed this off-forum, a while back. I was greeted by a bunch of naysayers and predictors of doom as well. On the other hand, i ran it by my old man, mechanical engineer by vocation, long-time road-racer by avocation. he loved it, thought it was slicker than gooseshit. Which is what I thought...
My under construction modified will use quad quarter eliptics, a la Miller Indy cars. The Millers used over and under quarter eliptics front and rear, check out the Miller V 16 in particular. We'll see how it works in practice.
I've got a couple hundred miles on it and no complaints at all. It launches straight, hooks up great and rides real nice. I haven't did any canyon bending with it yet, kinda want to work my way into that and keep an eye on everything to check for fatigue, loose bolts or what ever. I've only had it through the gears all the way to fifth real hard once due to some death wobble in the front that has cropped up a couple times and makes me a little nervous. The one thing I was most concerned about was spring wrap and wheel hop but it hasn't given the slightest hint of that. I kept the spring eyes real close to the axle to minimize the leverage the axle wrap would put on the springs, seems to have been the right geometry (so far).
Thanks for the up date. I'm trying to get the shop and parts ready to start my roadster. I had hoped to have a roller by spring or early summer. As always other stuff happens. Your design will serve me just fine.
Here is one my students built http://www.jalopyjournal.com/forum/picture.php?albumid=22623&pictureid=439942
Not sure if it's the right thing but I chose to have the wider end of the triangulation on the axle rather than the frame. I figured the upper mountings on the axle would take a lot less abuse fore and aft if the mounting point was closer to the wheel, if that makes any sense.
It does make sense to me. It would seem to give them more leverage to manage both the side and twisting movement. It would probably work the other way too but it wouldn't look like it would work.
The triangle upper link will work about the same in either position..However there is a roll center created at the single point created when the upper arms are extended to meet which imparts more sideways flexing to the springs which acts/results in the spring also functioning as a sway bar [only] because the front of the spring is solid mounted..Not necessarilly a bad thing...
I run a quarter elliptic car. I got em on both ends. The fronts are trailer springs from TSC the rears are from who knows what, I got them out of a pile in the scrap yard. Dont believe the nay Sayers mine rides like a Caddy. My buddy who helped with the build was not impressed with the suspension until we got back from the first Cruz night. He said I take my hat off to you sir that thing rides way better than I ever thought. My set up runs a third link or torque arm . The springs mount quite a bit lower than the centerline of the axle but the torque arms lower link is in line with the lower spring mounts. The front of the springs are captured in a box that allows for ride height adjustment. The front of the torque arm is a tie rod end hooked to a shackle that allows the axle to swing thru a different arc than the long torque arm . So far so good drives straight turns in well and burns the tires with no hop. I dont have to many miles on her yet, being we got her done just in time to put up for the winter. The front got new king pins to calm down a death wobble problem , that is made worse by having Bike tires on the front, thats gonna change also. Good luck with your set up and laugh in the face of the naysayer.
I race a quarter elliptic car..on the rear. 1959 bugeye road racing, works great. Love the feel and yes the springs and the upper links ..on the bugeye do act as a sway bar. If done right the quarter elliptic stuff puts all the mass of the rear suspension in front of the rear axle..lower polar moment of enertia. Moving the upper link front mounting point up or down can have a very positive affect on traction and weight transfer. Bobby Knighton here in Houston use quarter elliptic rear springs on his yellow 32 coupe that was very hard to beat for many years in the altered class.
It was my thought from study diagrams of both designs that with the upper control arms located on top center of the rear end housing there would be more torsional loading/flex on the mounts, probably a moot point if they are strong enough.
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