GG,Originally posted by Gruntguru:
Z, not sure if you noticed, ...
...
This is a very clever and innovative car with a very low suspension component count and one major suspension component doubling as an aero undertray. This design and future iterations are capable of great things.
Indeed it is!
Yes, I recognised it straight away. I would really like to see UWA finish this car and perhaps get it over to some Northern hemisphere comps next year. Any chance? Certainly, I hope future UWA teams continue with the concept.
To restress what you said above, it is a VERY SIMPLE CONCEPT, with a minimal part count. So much so that I doubt anyone would have believed it could work if it was only suggested as an "idea" on these pages...
Proof that the concept works, to some degree at least, is one of Rex's (?) photos on the Facebook page that shows the car parked with one front wheel on top of a couple of red and blue boxes, about 10-15 cm high. All other wheels are still firmly on the ground!
~~~o0o~~~
To any interested teams currently running conventional suspensions.
Some of the UWA concept and the Z-Bar sketch above might be combined to retrofit a fairly simple soft twist-mode suspension to a conventional wishbone car. This is something you might do to a previous year's car as a research project.
First, remove all normal springs (dampers can stay). Then, looking at bottom right of sketch, at front and rear of car fit lateral Z-bars to control heave and pitch only. These might be lateral steel or glass/carbonfibre leafsprings as shown, or else any conventional "third spring" arrangement. These do the job of UWA's "W" springs (silly me, thinking they looked like "E's"!), although the W's also provide axle location (clever!). Next fit an unsprung undertray, somewhat like UWA's.
The chassis is now only supported like a bicycle (with single spring at front and rear), so wants to fall over whenever going around corners. So fit a SINGLE lateral U-bar at about mid-chassis with its outer ends connected to the undertray tunnels, thus preventing body-roll (search Rex's photos). During cornering the body leans on this single ARB, which in turn pushes down on the outside tunnel, and lifts the inside tunnel.
These roll forces (up on inner, and down on outer tunnel) are passed on to their respective wheels by the tunnels acting as "balance beams". So LLTD (= ERMD in above sketch) is determined entirely by the geometry of the linkage (specifically, the ARB/tunnel attachment points), and not by any spring rates, or by any bumps or twist in the road.
Note that in the above sketch (bottom-right) there are two longitudinal torsion bars, acting as Z-bars, that control both heave and roll. This layout is well suited to production cars because of the easy packaging of the torsion bars, which are conveniently the right size to carry most of the car's weight (ie. heave loads), as well as the roll loads. The UWA single lateral U-bar is a simpler solution, although it does require the undertray, or some sort of side balance-beams to work.
Z