Pocket dictionary: Understanding Yaw
Posted Thursday, May 1 2014 at 01:00
Yaw is not a term that will show up too often in a conversation, but it is one that will affect you whether you understand it or not. The credit crunch still did a number on you even if you thought it was something made by Cadbury’s.
Now according to formula1.net, yaw describes the rotation of the car about the Z-axis.
I am sorely tempted to explain the X,Y and Z axis, but that might be a difficult hole to dig my way out of. Instead, let me put it this way. Do you remember driving on a really muddy road and the car began to slide around hopelessly?
It was facing forward, but somehow you were moving sideways; that is yawing. It is basically the difference between the driver’s intended direction and the car’s actual direction.
Let me make this clearer. This is Jeremy Clarkson on top gear.com:
“On snow or ice or gravel, we all know that a car will not stop or steer. And yet rally cars do both of these things. That means the whole thing is sorcery, and the people who do the driving must be witches.”
“I remember well the first time I drove a rally car. Men in corporate-branded clothing strapped me into the seat very tightly and explained what all of the levers did, but I could not hear anything above the sound of my own heartbeat.
I set off, gingerly, and arrived quite soon at the first corner. I turned the wheel, but the car continued to go straight on. So I braked. And this made no difference, either. The car maintained its speed and direction as though I wasn’t there. And then it fell in a ditch.”
The moral of this story is; In some conditions, cars just refuse to obey normal driver input. This is why modern cars now come with a system called electronic stability control or ESC.
According to how stuffworks.com, stability control detects discrepancies between the steering wheel’s direction and where the car is headed, then instantly makes corrections. By applying brakes on specific wheels for example, it is trying to bring the car back into your control.
It is worth noting however, that yaw is not always bad. It is absolutely necessary when trying to drift around a corner spectacularly, because then, the car is obeying a whole different set of rules. But I strongly recommend that you do not try this unless you are a professional rally driver. You will end up in a ditch or find yourself having supper with Jesus.