Small disscussion on locostusa.com:
http://www.locostusa.com/forums/viewtopic.php?t=144
I happened apon this a few minutes ago, and was very interested in it. very low shock design, pushrod, mumford linkage.
The first and second pics are digital renderings, but the third one is shown on an older mustang II
[Edited on 13/10/05 by derf]
Horizontal dampers are usually a problem. Citroen managed to make it work in the eighties. Rover engineers tried but failed to copy it. It's a good idea for space saving, lowering C of G and increasing luggage space. If you can make it work.
The Watts linkage is good but the rest I suspect is trying to be much too clever without any real gain.
[Edited on 13/10/05 by britishtrident]
Yes it's an excellent design, and would definatly fit in with the design of the locost frame. Since I saw it, and I am going to re-do my front
suspension. I have been contemplating re-doing my rear suspension along the lines of what is shown here. The way that it sits would definatly fit in
the chassis, and would also give a hight adjustability into my rear.
The only modification to the design is to get rid of the 3rd center link, and add a second set of trailing arms above the ones that are there.
Can anyone take a guess if the watts link will fit below the chassis?
That Mustang owner really went through a lot of cutting and welding to make a chevette rear suspension... Three-link suspension like this one (and the chevette) are pretty good for turning, although not much better than the locostīs 4 link. I agree the watts linkage is the only original thing there, the rest is just useful to impress your friends, but no better in the performance department, and heavier too.
Spot the two bolts in shear, and there holding all the weight of the car? I would'nt wan't is like that, it's not going to last
long.
Dan
Dan, look at the suspension mounts on most vans - all the ones i've seen in the traffic light queue have them mounted in single sheer. Its not the best practice but is ok if engineered correctly.
What's wrong with the standard damper arrangement?
And a sensible Watts Link has the crank attached to the chassis. Unsprung weight and all that. Only a seppo could dream up that nightmare.
The most interesting thing is those mufflers/silencers. By the look of the weld print through, they are Flowmasters, and date back to the mid eighties
in design. But, are very effective and create little back pressure.
They'd have to be the most sensible part of the whole car, and would do more for the total performance than that abomination of a rear
suspension setup.
[Edited on 13/10/05 by Syd Bridge]
Different angle.
It doesn't work correctly. The fixed arm means the axle will just pivot around the front mount and put unnecessary loads on the pinion and
propshaft. Nice use of different coloured paints, but other than that it's bullshit baffles brains thinking.
Edit.
The more I look at it the more it upsets me. Just looking at the crank arms and it doesn't take much to figure that the rate will fall fairly
dramatically. Daft thing is that with the pushrod mount being so low on the axle that there is room to put a vertical shocker unit anyway.
[Edited on 13/10/05 by gazza285]
Why the hell didn't they just do dual trailing arms AND the horizontal dampers?
That inane center arm would cause the whole rear axle to twist in relation to the propshaft.
It's fine if you don't actually expect the axle to move.
I can't see what locates the top of the axle at the wheel ends. It looks like it will pivot forwards. I don't think changing things for the sake of it does anyone any good. The Watts linkage is a proven method of locating axles as is panhard and mumford links but all that is doing is complicating something for no gain.
quote:
Originally posted by Syd Bridge
The most interesting thing is those mufflers/silencers. By the look of the weld print through, they are Flowmasters, and date back to the mid eighties in design. But, are very effective and create little back pressure.
They'd have to be the most sensible part of the whole car, and would do more for the total performance than that abomination of a rear suspension setup.
[Edited on 13/10/05 by Syd Bridge]
quote:
I don't think changing things for the sake of it does anyone any good.
Running a watts link horizontal like that would put the rear roll center at the center pivot point?
I would like to find some info on mumford link design but it seems to like the black box in programing that says "miracle happens here"
Dale
Hmm, all this work...and it's still a live axle. Effort better expended on a good IRS design IMO.
Didn't Lotus have a series of axle housing failures with their original three link design? Forces from accelerating and braking put torsional
forces through the axle tubes which aren't there with a 4 link setup.
I think some posters have missed the point - the pictured suspension is grafted onto the underside of an existing car that looks like it had cart
springs. With some ingenuity they've improved the axle location a million percent within the space constraints and made a nice looking job of
it.
You'd be insane to put it on a locost though . . . . .
cheers
Bob
oh yeah...
"I don't think changing things for the sake of it does anyone any good."
I change things for the sake of it whenever I get a chance..... I happen to think it's how progress happens!!
So who wants a go in my car when it's done ? ? ? ?
ttfn
Bob
quote:
Originally posted by Bob C
I think some posters have missed the point - the pictured suspension is grafted onto the underside of an existing car that looks like it had cart springs. With some ingenuity they've improved the axle location a million percent within the space constraints and made a nice looking job of it.
You'd be insane to put it on a locost though . . . . .
cheers
Bob
Then it's called improving it, not changing it, and is a completely different matter. If that is replacing a cart spring rear then it's
probably an improvement. I agree that he would have been better off with another set of trailing arms instead of the contraption bolted to the diff
though. edit:- I've just looked again and he could have mounted the shocks upright from the bolts that the bellcranks pivot on and saved even
more time, weight and effort and probably be more efficient.
[Edited on 14/10/05 by Peteff]
Here's a picture of a mumford link setup Dale.
There's a bit about it on the site as well here
hi gazza,
I think you missed my point - it's not in a locost is it? The installation photo shows you can't put the upper trailing arms in so the
chevette/ascona/manta style system has been used. Quite right, it's not better than a std. locost system but it's not in a std. locost etc.
etc.
FWIW I agree it would be simpler lighter & probably better with vertical dampers & it looks like there's room. There's plenty not to
like, rod ends holding whole weight of car stuck out 3" on a bolt & spacer, questionable triangulation of the back face of the
'box' - at least the bellcranks on the photo look sturdier than the rendered ones (gorgeous rendered images though!).
night night
Bob
I've looked at the pictures (agreed, nice renderings) over and over again and the only answer I can come up with is "because he
could"!
It's not progress, it's overkill, it's 'king ugly, it doesn't appear sturdy or safe and it doesn't look like it would
actually work very well, if at all.
But, if I had his brain in my head and the same amount of spare time and cash, I would probably have done the same thing.
quote:
Originally posted by gazza285
Different angle.
It doesn't work correctly. The fixed arm means the axle will just pivot around the front mount and put unnecessary loads on the pinion and propshaft.
quote:
Originally posted by Syd Bridge
What's wrong with the standard damper arrangement?
And a sensible Watts Link has the crank attached to the chassis. Unsprung weight and all that. Only a seppo could dream up that nightmare.
snip
snip
[Edited on 13/10/05 by Syd Bridge]
quote:
Originally posted by MikeRJ
Hmm, all this work...and it's still a live axle. Effort better expended on a good IRS design IMO.
Didn't Lotus have a series of axle housing failures with their original three link design? Forces from accelerating and braking put torsional forces through the axle tubes which aren't there with a 4 link setup.
quote:
Originally posted by cymtriks
quote:
Originally posted by gazza285
Different angle.
It doesn't work correctly. The fixed arm means the axle will just pivot around the front mount and put unnecessary loads on the pinion and propshaft.
Not quite!
The central arm has a floating link at the front so it cannot locate the axle fore-aft.
What it does do is to stop the axle from rotating. The two trailing links provide fore-aft location, a third, or fourth trailing link to prevent the axle from rotating isn't needed as this movement is prevented by the third central link.
The complete set up goes like this:
Translation:
fore-aft by the two side links
sideways by the Watts linkage
vertical by the springs
Rotation:
About car centre line by the springs
About Axle centre line by the trailing link and the central floating link
About the vertical by the trailing links
That's all six taken care of and not conflicting so it does work!
Having said that how many links are there?
2 pushrods
2 bell cranks
2 trailing links
2 lateral links
1 Watts link centre
1 trailing arm
1 trailing arm vertical support at the front
That's 11 links!
What on Earth's wrong with a Satchell link? Just four links, two upper trailing and two lower angled from the ends of the axles to the back of the transmission tunnel. All for links being rubber bushed or spherical jointed. Simple. Cheap. Works well.
I ment that it prevents free rotation.
The central link could be described as a torque reation link, it transmits no fore-aft loads at all but is loaded in bending as it as it takes up the
torque reaction.
I still reckon Satchel link would be better though it would be hard to get the right angles for the lower tubes in the available space. Perhaps an
axle mount swept back from the axle centre line would be needed, or a stronger lower tube, say 1/8 wall thickness.
Has anyone tried a Satchel link?
On the mumford pic shown. Am I correct in that the roll center is the joing point of the 2 long arms if their lines where extened to meet in the
middle.?
Dale
quote:
Originally posted by britishtrident
Actually in the real world nearly all Watts linkages have the crank mounted on the axle,
[Edited on 15/10/05 by britishtrident]
I see a thousand watts links bolted to the diff every day- crown vic police crusiers- but I believe it is done that way as its probably a couple of
seconds faster to put in and does not require a center section in the frame to bolt the section to.
You would be suprised as to how well the big car handles its 4 link live axle same as the locost with a coil over spring type of rear -or air bag.
and unequal length A arms on the front.
Dale
So - has anyone driven a powerful car with this kind of "torque tube" wheel torque reaction control? By my reckoning the wheel torque
reaction will try to compress the springs leading to extra "squat". Does the extra squat lead to extra wheelspin?
cheers
Bob
Rover used a torque tube on the Sd1 including the racers, Opel at one time used right across the range including the Comodore racers.
I think also the Chevette HSR 2300 might have used a torque tube but can't be sure.
rover sd1
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sd1
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