How is a helicopter able to stay up in the air in one spot for a long time?

Answer 1

The rotor of a helicopter is similar to the wing on an airplane, with the airflow over it maintained by the engine turning it.

The amount of lift that an airfoil produces increases roughly linearly with an increase in the airspeed over it, and roughly linearly with the angle of attack (the angle or pitch that the airfoil makes compared to the direction from which the air is flowing). Thus, lift or thrust from the rotors could be changed either by changing the rotor RPM or changing the pitch of the blades. While some R/C helicopters control thrust through changes in rotor RPM, due to the amount of angular momentum of the blades, that approach is not practical in real helicopters. Real helicopters control thrust thrust through a control called a "collective". When the pilot pulls up on the collective, the pitch of the rotors increase (while maintaining a constant RPM) thus increasing thrust.

A control called the "cyclic" can be used to tilt the rotor disk (by changing the pitch of the rotors as a function of where in the rotation they are) and vector the thrust to move the helicopter forward/backwards and left/right.

Finally anti-torque pedals controlled by the pilot's feet control the amount of pitch (and thus thrust) in the tail rotor. These are necessary to counteract the torque from the main rotors.

To maintain a hover in one spot, the pilot must be constantly applying small control corrections. Changes in any of the controls collective/cyclic/pedals usually necessitate changes in the others. It's like balancing a pole on your finger, you need to continuously move your finger to keep the pole upright, but if you move too much the pole will wobble and fall.

The corrections that the pilot needs to make to keep the hover in control are generally so small and quick, that if you try to think about what input you need, it will be too late. It needs to be learned as an automatic response that you can do without consciously thinking about.

Answer 2

Even though this seems like a joke, it's not. The difference between aircraft and helicopters are that aircraft use air to lift them, but helicopters just beat the air into submission. Helicopters have angled rotors which are designed to push the air down, and therefore the helicopter up. The same principle applies to moving left, right, forward, and backward. Aircraft need to be moving at least 69 MPH (depending on the type of aircraft) to stay in the air, but helicopters have no need for motion because they just propel themselves upwards, similar to all other directions. I hope I was helpful.
- Malcolm

Answer 3

Helicopters have the ability to hover; that is stay in one place in the air without moving forward.
The reason for this is the wing. On conventional aircraft or "fixed wings," the aircraft is able to stay in the air by means of the flow of air moving across the wings creating lift. They must therefore move forward through the air to create this lift. Helicopters have moving wings; that is the rotor is the wing. As the rotor moves atop the helicopter, it creates lift. If you were to look at the profile of a helicopter rotor and compare it to the wing on a regular aircraft, they would appear very similar.
So helicopters create lift because the rotary wing atop the aircraft moves through the air without the need for the helicopter itself to move forward for air to flow over it.
Just like fixed wings however, helicopters gain more lift as they move forward through the air increasing the airflow over the rotor or "wing."

Answer 4

on fixed wing planes the forward movement allows the wings to 'lift the plane' But it has to keep going forwards to keep it up. On a helicopter the 'wings' is the rotor and the circular movement lifts the plane. So providing the rotors keep turning the helicopter will stay up without forward movement. The pilot can decide whether to go forward, backwards sideways,or just stay where it is, by using the basic controls.

Answer 5

Martin, Pilot and others gave you the correct answer (the hover)...

After 15 years as a US Naval Aircrewman (10 years in Helicopters):

"We beat the air into submission!!"

Answer 6

Its all the skill of the pilot in balancing all the forces acting on the helicopter. Back and forwards, left and right and gravity with the engines thrust.
Stand on one leg for ages and you will see what I mean, as well as getting some strange looks lol.

Answer 7

The helicopter can hover for a time but not a long time as the rotors spin they pull the air from above them and push it down as this happens there becomes a lack of air to move and the helicopter fall until it can gain enough air to keep itself up again !

Answer 8

Helicopters are fitted with a special sensor that detects vacumm pockets in the air and when it finds one and enters it ,it can stay there indefinitely.

Answer 9

The Blades of the chopper create lift. The faster the spin the more lift is created. As the blades spin they are designed at an angle to froce the air downwards so pushing the copter upwards. The rear blades stop the chopper from spinning out of controll, they also give the direction for the chopper which are controlled by foot pedals..The pilot tilts the Blades against the air creating motion to fore or aft. If the blades are not angeled against the air the chopper remains still or hovers..The acceleration and forward motion is controlled by a shaft between the pilots legs. Left and right is controlled by foot pedals..

Answer 10

Because the pilot has got one steady hand!!!