What does the gimbal yaw motor do?

[YuKay]

Is this what turns the bird? Or can the camera yaw on its own?

 

[joshmentele]

Is this what turns the bird? Or can the camera yaw on its own?

View attachment 3015

The yaw motor will stabilize the footage so that it doesn't shake from left to right when flying.
The drone is turned by spinning the two clockwise motors faster while simultaneously spinning the other two slower.

 

[YuKay]

So it might be possible in theory to give the pilot some control over the gimbal yaw? Is there any leeway for the camera to turn, even 5-10%, without finding a leg?

 

[joshmentele]

So it might be possible in theory to give the pilot some control over the gimbal yaw? Is there any leeway for the camera to turn, even 5-10%, without finding a leg?

They could possibly do that, but it would reduce the amount of stabilization that can happen on fast turns. The mavic 2 has that capability but its yaw motor turns quite a bit farther than that on the Evo.