<VV> Fw: Fw: Camber Compensator

[kenpepke at juno.com]

The term 'Camber Compensator' is somewhat a misnomer.  It could more accurately be called a semi elliptical transverse mounted floating leaf spring.  In the case of the 1964 Corvair model year it would be better called a 'positive camber limiter.'

Doug, you have correctly identified the function of the transverse leaf spring as it affects the swing axle models of the Corvair.   But, it is the softer spring [and the heavier roll / sway bar] that increases the degree of understeer as it was relative to the original design.  This change noticeably affects the feeling of the vehicle.  It does not improve the vehicle handling.  In fact, in terms of lateral acceleration, it may have decreased the vehicle's actual performance; that is, it slightly reduces the rate of lateral acceleration attainable in the earlier vehicles.  This condition could have been generated simply by changing to a softer rate spring.  It is not necessary to add this transverse spring to carry the weight of the car nor was it necessary to incur the added production expense.  Therefore, that may not have been the actual GM intention.  

The side benefit, which is more likely the intent, is a reduced reaction to jounce / rebound.  The geometry of the suspension linkage determines the location of the rear instant roll center.  That combined with the from instant roll center determines the roll axis of the vehicle. The roll centers are somewhat dynamic with the motion of the suspension.  Spring rates and 'roll / sway bars' control the degree of roll and distribute that control in a front to rear ratio.  Under lateral acceleration the spring is in constant compression.  Tuck under and the resulting 'jacking' action comes only when the vehicle encounters an undulating surface putting the suspension into alternating jounce and rebound motion.  Under extreme conditions this can cause 'tripping' and perhaps digging in of the rim resulting in instability and possible vehicle roll over.  By adding the transverse spring Chevrolet limited the angle of maximum droop at the rear wheel and the resulting dramatic increase of positive camber should the vehicle become sufficiently airborne to extend the spring to or near its maximum length.  The result is the vehicle 'lands' with the tire more close to vertical therefore far less likely to trip or for the wheel to dig into the ground / road.   

This limiting of droop could have also been achieved by using a shorter shock absorber / dampener.  There are two main objections to using the 'shock' to limit droop.  1.  Shocks are far better at controlling in compression and 2.  the stop point on a shock at full extension is positive and, over time could cause the shock housing to fail, while that transverse leaf spring cushions the droop at maximum.
Ken P  


******************************
From: Doug Mackintosh <dougmackintosh at yahoo.com> wrote:
To: Virtual Vairs <virtualvairs at corvair.org>
Subject: <VV> Fw:  Camber Compensator
Date: Sun, 19 Sep 2010 02:05:38 +0000 (GMT)


&#65533;-- Doug Mackintosh
Corsa member since 1996
Corsa/NC member since 1996, Virtual Vairs member
Corvair owner 1969-1971 and 1996-on 




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