Colin Chapman did something very similar many years ago. Apparently the story goes, the racing rules insisted that the standard live rear axle had to be used plus the original drum brakes in a particular racing class.
So Colin fitted the live axle allright, complete with original drum brakes bolted solid to the chassis, and then fitted a very light semi trailing arm rear suspension with sprocket drive.
It was rather more ingenious than that effort, because it had some rear camber compensation. The unsprung weight and camber compensation of Colin Chapman's effort would have been a significant advantage over the leaf sprung live axle guys.
I don't know what the scrutineers said, but I would love to have been a fly on the wall during that discussion !
I'd be interested to know what drove them towards that setup - it looks heavy and has remarkably poor properties in single wheel bump.
On the other hand it would be the work of a moment to turn it into a twist beam. I rather like twist beam suspensions, they seem like a very sensible solution for a light car. In this case, where axle tramp and so on is not going to be a concern, I'd have thought they'd work well, with a de Dion diff, rather than messing about with power transmission through the beam itself. On the other hand they save the weight of 4 CV joints.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
I'm not sure what the design is supposed to offer. It seems all the claimed properties are available from a double wishbone setup with a little judiciois design and tuning.
One of the advantages I see is that you have camber gain in roll, as with sla setup, but unlike sla there is no camber gain in squat or heave. Of course, this advantage would be better suited to a high powered application such as a racecar.
One of the advantages I see is that you have camber gain in roll, as with sla setup, but unlike sla there is no camber gain in squat or heave. Of course, this advantage would be better suited to a high powered application such as a racecar.