How does a helicopter fly

Before it became a reality, the idea of vertical flight had engaged the imaginations of engineers for centuries.
Leonardo Da Vinci sketched what he called an aerial screw in the fifteenth century.
In the nineteenth century British engineer Sir George Cayley drew designs for what he dubbed an aerial carriage
But it wasn't until the early twentieth century--shortly after the famous flight of Wright brothers--that the first hoppers got off the ground.
Whereas an airplane relies on forward motion to circulate air against its wings and create lift, a helicopter uses rotating blades for lift.
The pilot can control the angle of the blades against the relative current of air in such a way that they push the air down (and the craft up) or, following Bernoulli, create a high pressure zone under the blades that lift them up.
Tipping the rotor forward produces motion forward and up, while tipping it backward moves the copter in the opposite direction.