How does the helicopter stay stationary in the air?

Answer 1

Two things keep a helicopter flying, and another keeps it flying straight.

To take off:

1) The blades are shaped like the wings of an airplane and create a difference in pressure (high underneath the wing, low above). This difference in pressure "pushes" the helicopter upwards (lift). But because of gravity, however, there might not be enough lift to take off from the ground.

2) In order to take off, the blades must rotate at supersonic speeds (to be stronger than gravity's push downwards), this make it possible to gain altitude.

To "Fly:"

1) A helicopter's blades in air act like a boat's propeller in water. If the blades rotate at an angle, it will start moving. To make the helicopter hover, the blades must be perfectly straight up. At the same time, the rotating blades make the helicopter itself rotate the other way (about the axis of rotation).

In a GPS, the helicopter would not be going anywhere like this (with no angle on the blades), but the Direction at which it is looking will be changing in circles

2) Helicopters need a way to fix this crazy-out-of-control spinning. They can use a tail rotor for this, but they can also use a "twin" set of blades that rotate in opposite directions (counter-rotating blades).

With the addition of counter-spinning blades, now the GPS will be pointing at 1 direction.

in summary:

1) By keeping the blades rotating fast enough to be lifting with the same force as gravity is pushing down, the altitude is kept the same.

2) By keeping the Blades from spinning at an angle, the Helicopter does not move to the sides.

3) By using a counter-rotating blades set, the helicopter is able to keep looking at one direction.

with these 3 things, Helicopter are able to hover in air, and their GPS can be kept and a fixed height, at fixed position on a map, and at a fixed direction.