Drones (Quadcopter type)

[Cam]

How is the yaw achieved? I understand how the pitch, roll and altitude is achieved, but not yaw.

 

[Finnthedude]

On a quadcopter, 2 propellers spin clockwise (CW) and 2 anti-clockwise (ACW) and are paired diagonally. This 50/50 split evens out the rotational forces for straight and level flight. To yaw, these forces need to be unbalanced. To spin clockwise the CW motors spin faster and/or the ACW motors spin slower.

Finnthedude.

 

[Cam]

On a quadcopter, 2 propellers spin clockwise (CW) and 2 anti-clockwise (ACW) and are paired diagonally. This 50/50 split evens out the rotational forces for straight and level flight. To yaw, these forces need to be unbalanced. To spin clockwise the CW motors spin faster and/or the ACW motors spin slower.

Finnthedude.

Thanks

Yeah, it's using reactionary torque, but what I don't get is if the paired diagonally opposed motors are at different speeds i.e. Front Left/Rear Right Vs , Front Right/Rear Left, my thought is that the drone will tilt diagonally due to the reduced downward thrustat one of the diagonals ???? I am obviously missing something!

 

[Finnthedude]

It doesn't tilt diagonally because you have 1 port motor and 1 starboard motor spinning faster so they balance. Conservation of momentum makes it move in the only direction of unbalance i.e yaw CW or yaw ACW.

If you only increased the speed of one motor instead of a pair, the aircraft would indeed yaw AND tilt diagonally.

There is a nice explanation HERE "Quadcopter Motor Direction For Yaw" about halfway down the page.

Finnthedude.

 

[Cam]

It doesn't tilt diagonally because you have 1 port motor and 1 starboard motor spinning faster so they balance. Conservation of momentum makes it move in the only direction of unbalance i.e yaw CW or yaw ACW.

Finnthedude.

Yeah, I've just lifted, by two hands, the front left and rear right propellers and the craft is in balance. I think I have it!!! Thanks

Cam