Well the frequency of accidents as concluded by the government in 1972 refutes your assertion of a high frequency rollovers.
This fact is directed specifically at you… If the tire pressures were set as specified in the owners manual by Chevrolet, the cars handling would have been safe, benign understeer at the limit.
Those Tatras oversteered as designed throughout all their models. I have seen promotional films of 60s era Tatra 603s (?) hanging their tails out from beachfront asphalt to snow covered alpine passes.
The earliest Tatras had front suspension designs that made the front tires roll with exactly the same angle as the body. As the car rolls the front tires lose traction balancing the oversteer tendencies of the rear engine. The swing axle rear gains traction (from negative camber) while the front loses traction which creates understeer. Clearly Tatras didn’t quite lose their oversteer.
VWs and Porsche 356s and 911s were designed exactly the same. Their trailing arm front suspensions and front struts in the 911 reacted the very same way. Each could still hang their tails out if provoked.
The Corvair had a double A-arm suspension which would not have reacted the same way. It would have maintained traction at the front a bit better than a VW or Porsche.
That is true, but because the specified inflation pressures were so unusual (at least, for Americans), GM should have placed a notice on the sun visor, advising Corvair owners of the importance of the wildly-different front/rear inflation that was necessary in order to achieve safe handling.
Somehow, they managed to place a cardboard sleeve on the sun visor regarding the operation of the car’s heater, but they failed to do something similar with the much-more-important tire inflation bias.
Corvair owners weren’t expected to delve into the Owner’s Manual for the operation of the heater, but they were expected to do so for something that could–literally–be a matter of life or death.
That statement about tire pressures, which I agree with by the way, also seems to imply that not adhering to those pressures was partly to blamej for the rollovers.
I forgot which magazine it was in the 1960s that tested the Corvair, but they stated about half way through the write-up that the handling “felt improved” with all tires inflated to a cold 26psi.
I don’t know - I wasn’t there for those tests.
When I was in my teens, I read Rudolf Caracciola’s autobiography. He drove for Mercedes, and even though they competed with Auto Union, he felt comradeship with the AU drivers. He was very outspoken about the extreme oversteering of the AU race cars, which he said had led to the death of several experienced AU race drivers.
Pressure spec was 15 psi front 26 psi rear. Makes sense considering the 35/65 front to rear weight distribution.
Believe me I know that better than half the Corvair-driving public probably did 60 years ago - I’d be out to the car every other week verifying those cold pressures, lol!
the mid 30’s cars.. had 6 liter supercharged 16 cylinder engines with tires about 6 inches wide PLUS the swing axle rears. Those car were going to oversteer no matter what! The low moment of inertia - an advantage in most cars - made the AU cars wicked tricky.
The Mercedes-Benz cars were mid-front cars - the engine was behind the front axle - and used deDion rear suspension. The exta moment of inertia from this layout made them more stable. They oversteered for the same reasons - skinny tires and tons of power - but would be a bit more stable.
The ‘38 and ‘39 AU cars switched to supercharged 3 liter V12s as did Mercedes. AU adopted a de Dion rear suspension but stayed with the mid-engine layout. This made them much more stable.
Its never just one thing that causes problems, it is always a combination of things.
As Mustangman pointed out the problem isn’t just the Swing Axel but on a combination of design factors. For anyone further interested in the Corvair and Beetle IRS Swing Axel issue there’s a great Wiki article at
“Jacking” on suspension unloading (or rebound) causes positive camber changes on both sides, which (In extreme cases) can overturn the car.
Change in camber due to cornering forces can cause loss of rear-wheel adhesion leading to oversteer—a dynamically unstable condition that can cause a vehicle to spin. This is an especially severe problem when a swing axle is used in a rear-engine design, because of the greater side-g forces on the rear wheels from the mass of the engine. Camber changes during deceleration can increase the severity of lift-off oversteer.
The presence of the swing-axLE itself is related to, and a catalyst for, the jacking forces and camber changes described in that article.
Maybe not the sole cause, but one of the root causes.
While it never came to fruition, Auto Union had plans for the Type 52 Schnellsportwagen passenger car, which embodied the engineering of their rear-engine race cars. If it had been built, it probably would have resulted in even more deaths for N a z i officers than the original Tatra sedans.
Tear-drop - the ultimate aerodynamic form.
