Hi,
I ran across this while checking on swing axle suspensions -- I was looking because I thought that VWs had the same issues as Corvairs. Apparently the early ones did. I can't say that I know why the roll center is so high on a swing axle suspension, but there are a lot of things about suspensions that are pretty vague to me.

"The problem with the swing axles though, and the reason that VW stopped using them (and why Chevy got crucified over the early Corvair), is that the roll center ends up being extremely high, like 3-4" higher than axle centerline high, which is dangerously close to the center of gravity height.. And the roll center moves around a lot with suspension motion. So you have a suspension that already is extremely resistant to motion in roll, in the rear, in a rear-heavy chassis (not great), and then if you go over a crest or lift off the throttle (already a bad idea in a rear engined car) the roll couple can actually change signs with the roll center being HIGHER than the center of gravity.

When the roll couple changes signs, the suspension wants to lean "IN" to the turn. But since the CG is above ground level, the car won't. The outside suspension just extends.

This is swing axle jacking"

So I guess that Nader should have gone after VWs too .

hj

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The VW was much lower power and was probably driven less aggressively in most cases. In the Corvair there was a transition from understeer to oversteer somewhere just under 30 mph. Add all this to the early swing axle issues you note and all of a sudden mom is going bass-akwards into the ditch.
I don't know the breakdown of Corvair accident stats regarding the nature of the crashes.

 

There's a good article and video on this. I'll link to it later.

 

This is the video:
https://www.hagerty.com/media/videos...vair-kill-you/

More commentary on the same:
https://www.roadandtrack.com/car-cul...dful-to-drive/

As to VW, those were down on power and probably not driven as aggressively as the Corvair might have been. The video mentions the VW and the Porsche 356 which also had the swing axle.

Also as to Nader and VW:
https://www.nytimes.com/1971/09/12/a...-by-nader.html

But VW wasn't GM. And they didn't do the stupid things GM tried to do to discredit Nader.

 

Wow, learn something new. I had heard about the Corvair death trap and Nader reports on it as a child, way back before there was any thought of being an auto tech, especially surprising being a suspension specialist that I am now and never heard of this swing axle design so I looked it up before posting and HOLYHELL!!! It's easy to see what a design mistake that system was, also noticed Mercedes used and abandoned it in the 50's.

Thanks for the 411.

 

Another aspect of Corvair's vs VW was they did NOT have higher powered engines available from the factory---my Dad had one of the Spyder's that had somewhere near 150 HP.

Most people have far more problems when a vehicle goes into an under steer attitude as its correction is not as intuitive or taught as is over steer. Its safe to say a Corvair WAS "dangergous" when the inexperienced driver pushed on past its suspension's capabilities. We also have to remember tire technology was far, far behind what's available which is another factor to consider.

The Wikipedia page is an interesting read if you're so inclined: GM Corvair