Axle rotation (torque reaction) was controlled by the torque tube. The only rods I see in that picture are brake rods.
The forces on the axle under acceleration will be pushing on the lower link and pulling on the upper. The spring would be more suited to the upper. Best application of these is probably using them with a standard triangulated 4-link, as Langy shows.
There is no torque tube, but when I looked closed I did see it has a 4 bar. That looks like a good setup langy. I do have concerns about the spring taking the forward thrust on mine, but the it does on full parallel leafs too.
I did at first but they aren't torque tubes. A torque tube is a solid tube the driveline runs inside of.
If I read these right, your statements contradict themselves..... Langly has the springs on bottom.... You think the spring is better on bottom or top?
But the suspension in your diagram isn't a 1/4 eliptic. I would say put the triangle the other way, widest part on the rear end and narrower where it mounts to the frame. So yes.
If I were using the springs as the triangulated upper links, I would build it just as the drawings show in your post...for ONE good reason. For the suspension to allow the axle to articlulate and move correctly, the springs are going to have to twist, or you will have to use a huge bushing or spherical joint in the spring eye. The amount of twist they will see mounted together at the center of the axle is much less than if they were mounted out near the ends, because the housing isn't moving as far near the center (in roll ONLY). For 3" of body roll, you would have nearly that much movement out near the end of the housing, but only a fraction of an inch at the center. A lot of people will say it doesn't matter on a hot rod, and maybe it doesn't. Personally I'd choose to have it operate as efficiently as possible.
No one has answered my question. If you use the spring on the bottom as a link, when it compresses and lengthens won't it change the pinion angle? Is it enough to make a difference? In my opinion ( I'm not an expert ) the best way to use the quarter elliptic spring is along with a 4 bar set up ( triangulated or straight with a panard bar ) and shackles. I'd like to use something like this on a future project so I'd like to know which is the safest and most bullet proof.
This is an interesting thread for me, I'm working my way to the back of the car and playing with 1/4's
Del, I've been waiting for more experienced builders to answer your question. Having built one rod with this set up in front and one with it in the rear, I can speak to the function of those two cars. The amount of pinion angle change through the range of motion proved to not be a problem. The springs and bars were about 18" long and I planned for just 4" of wheel travel. Spring elongation is minimal under this cir***stance. I posted a picture on page one on this thread, if you care to go back and look. The spring is on top. Not visible is a diagonal panhard bar that runs between the lower bars, prostreet or drag style. That panhard bar set up is considered less desirable than a conventional set up but it worked fine for me. Edit: I found a pic from the rear showing the diagonal locator.
I believe it was covered earlier, but yes; absolutely the best way to use the 1/4 elliptics is with 4 solid links and shackles. That way the spring is just a spring.
Some old British sports cars used shackless quarter elliptics and some very early Indy cars used dual shackless quarter eliptics. It works. I also have a '27 roadster with quarter elliptics on the front, with shackles. Obviously, that works just fine. It all depends on how much originality you wish to put into your build.
I'll venture a guess... if the spring (no shackles) and the matching bar are the same lengths, then pinon angle change should be minimal on a parallel 4 bar. But there may be an advantage / disadvantage to using the spring in either the lower or upper position, in the same way 4 bars are adjusted on drag cars to improve traction when the car squats under hard acceleration. If so, it will take a real suspension engineer to tell you where the best location for the spring is. If the change is negligible, then it probably won't matter that much. How's that for a waffeling, non answer? Gary
It's negligible...at least it was on the setup I did...I ran springs as the lower bars and triangulated uppers and had it set up so it had zero change in pinion angle when the suspension flexed. Rode very nice.
I have mine set up pretty soft to check the pinion through the range of travel and I see no noticeable change in pinion angle. I did not put an angle gauge on it though.
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