Why do quadcopters have for rotors instead of three. Now that's an interesting question. I think it's because it keeps the whole system simple.
Normal helicopters will "feather" the blades during each rotation controlled with the cyclic. With a quadcopter, the propellers don't have to vary their pitch at all, and all motions can be controlled by varying motor speed. To roll or pitch, a single motor is slowed. To yaw, the two blades that rotate the same direction are sped up by the same amount that the other two are slowed down so that altitude is kept constant. And elevation is changed by increasing all rotor speeds. So it's a lot more mechanically simple than having a cyclic. I think it could also be done with 3 rotors, but the programming to make yaw movements smooth would be difficult, because two rotors would be spinning one direction and only one counter-rotating.
Why do quadcopters have for rotors instead of three. Now that's an interesting question. I think it's because it keeps the whole system simple.
ReplyDeleteNormal helicopters will "feather" the blades during each rotation controlled with the cyclic. With a quadcopter, the propellers don't have to vary their pitch at all, and all motions can be controlled by varying motor speed. To roll or pitch, a single motor is slowed. To yaw, the two blades that rotate the same direction are sped up by the same amount that the other two are slowed down so that altitude is kept constant. And elevation is changed by increasing all rotor speeds. So it's a lot more mechanically simple than having a cyclic. I think it could also be done with 3 rotors, but the programming to make yaw movements smooth would be difficult, because two rotors would be spinning one direction and only one counter-rotating.