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The helicopter has been with us for many years, since the first commercially viable production model in 1936. Their ability to hover, take off and land vertically, and operate at low speeds has carved out a niche for helicopters for decades. However, their dominance over the vertical aircraft airspace may be in doubt as a new paradigm emerges; that of the Quadrotor.
The quadrotor is similar to a helicopter like a bicycle is to a car. Instead of two opposed rotors the quadrotor has 4, mounted symmetrically on the body of the vehicle. This gives the quadrotor far greater control when in the air. A helicopter changes its angle of attack from the main rotor in an ungainly fashion, a quadrotor merely has to trim speed/torque from one of its rotors to accomplish the same effect. In case you were wondering how both vehicles control their various control surfaces, actuators are once again the answer, with linear actuators providing several essential motive forces in fully scaled up helicopters.
But just how good are these quadrotors? Helicopters have ruled the roost for decades, surely it’ll take more than a shoe box with rotors on each corner to retire them! To see them in action check out some of these videos:
This video demonstrates the far greater control possible with the quadrotor’s four engined design, which in turn leads to its programmability. Early in the video you see one do three vertical flips(!), and near the end a swarm of the quadrotors fly in an intersecting figure eight pattern. Since there are far fewer variables involved in controlling a quadrotor (as opposed to a helicopter) programmable, computer controlled flight suddenly seems a realistic possibility.
That last video was kind of ominous, let’s end this with another video of quadrotors playing music instead:
Of course, these quadrotors are all quite small. One could argue that helicopters are in no danger when these quadrotors are barely larger than sparrows. The idea is gaining traction though, and some full size vehicles using the same concepts already exist. For example there’s the Bell Boeing V-22 Osprey, a two rotored vehicle already in military service. More exciting, Bell Helicopter and Boeing are also working on a 4 rotored version: The Bell Boeing Quad TiltRotor.
