Loading…
Rotation of the vehicle around its vertical axis. When a car turns into a corner, it yaws — the nose points toward the inside of the turn. Controlling the rate and amount of yaw is central to cornering technique.
The textbook Vehicle Dynamics defines the physics: "the moment M results in an angular momentum L. The angular momentum can be calculated by the integral Jz times the yaw rate, where Jz is the mass moment of inertia for a rotation about the vertical axis." It explains that "the yaw moment must be compensated for by cornering forces, which means that the driver has to countersteer." Going Faster! (Lopez) illustrates the driver's perspective: "At corner entry the car not only changes direction, it rotates around its center, creating a yaw angle. At corner exit, the rotation is in the opposite direction as the car goes back to zero yaw entering the following straight." The text notes that "the initial steering input frequently has to be adjusted to maintain the proper angle" — too much yaw means excessive tire scrub and slower exit speeds, while too little means the car hasn't rotated enough to point toward the exit.