Why Continuous Rotation?

The 401cr can do something other simulators can't: It provides a high-quality, one-to-one ratio between vehicle rotation and simulator rotation, without washouts or inverse forces.

Vehicle yaw is one of the most critical, if not the most critical, forces a driver feels on-track. Sure, it helps you know whether there's slip angle, and how much, but there's more than that: It tells you where your car is in space and where it's going. There's a reason drivers talking about their last stint move their hands in arcs! So yaw sense is a critical component of vehicle simulation, but why is continuous rotation important specifically?

A limited-rotation simulator requires washouts, and washouts mean changes of direction — and changes of direction can be felt. The lower the rotation range, the worse the problem is, and feeling something when you should feel nothing is the only thing worse than feeling nothing when you should feel something.

The 401cr gives drivers exactly — and only — what they’re expecting, leaving them free to drive instead of translating the simulator’s cues. To get a sense of why this is, take a look at the video loop below.

In this right-hand hairpin, the limited rotation simulator (on the right, with +/- 30 degrees of yaw) saturates part-way through the corner and stops providing meaningful cues, before suddenly starting to move again after the corner exit. The driver feels his car stop turning during the middle of the corner, not turn through the second half of the corner, and then turn to the left while the car is going straight!

Competing simulators' yaw is almost always less than the +/- 30 degrees shown here. At best, drivers feel scaled down or cued vehicle rotation; at worst, they turn one way while the car is turning another.

At best, drivers feel scaled down or cued vehicle rotation; at worst, they turn one way while the car is turning another.

For example, on a short oval, the car rotates through 360 degrees. The 401cr makes a continuous turn, but during half of the lap, a limited-yaw simulator is turning right while the car is turning left or going straight. This applies for any corner more than half the simulator's maximum rotation angle, and no amount of tricks can compensate.

In response, some argue that simulator yaw is for slip angle (sometimes causing simulator makers to try to re-brand yaw as a "traction loss" axis). But 1:1 yaw feedback aids significantly in your ability to position the car, even at zero slip angle. You can feel the apex instead of seeing it. And cueing slip angles results in an 'edge' of opposite yaw force with every motion as the simulator pulls back to center.

Further, a 1:1 ratio is necessary when dealing with many small steering corrections happening on top of a large, fast rotation. This isn't something a limited-yaw simulator can handle, but it's absolutely essential to understanding a car at the limit. And only continuous rotation can do it.