The Helicopter can hang and thrust forward but the plane can´t.Why?

Question

What makes the Helicopter able to hang and also thrust forward and at times backwards while in the air and the aeroplane cannot perform these acts.Why?
I love the Helicopters and want to be the pilot of one in future.Educate me more on the flying mechanisms of this adorable flying little thing.

Answer 1

Almost all of the answers you have gotten so far are accurate. Let me try a slightly different approach to the answer and see if this helps.

First, you have 4 factors that relate directly to allowing or preventing a craft from flying. Each factor must be dealt with or you will not have forward flight. 1. Lift. 2. Gravity. 3. Thrust. 4. Drag. Lift and gravity are opposing forces as are Thrust and drag. Gravity will always pull you down to earth. Drag will always limit your ability to move forward. Lift must be created in enough quantity to overcome the force of gravity or you will always be on the ground.

Now, with a helicopter, lift is created when the engine turns the top rotors fast enough for the rotors to create enough lift to overcome the force of gravity. I won’t go into the fact that the rotors are also shaped like wings as that is for the next class on aerodynamics. The tail rotor is only there to keep the nose of the craft pointed in the direction of choice. All lift is from the top rotor. Interestingly enough, all of the forward motion also comes from the top rotor. It is a trade off. The more forward motion you get from a top rotor, the less lift you will get. This is the trade off that requires the helicopter pilot to balance out the forces. It is also the reason helicopters can hover. If no forward tilt is applied to the rotors, there is no thrust so no force to overcome the drag.

So, what about a fixed wing airplane? For this situation, you have the prop (I’ll work with basic aircraft to prevent confusion) creating the forward thrust to overcome the drag. You have no lift created until you first overcome the drag and start moving forward. Once moving forward at a high enough speed, the wings will start creating lift (again, you’ll have to wait for the class on aerodynamics.) When the plane is going fast enough, the wings will be able to create sufficient lift to overcome gravity and you have flight.

As you can see, both flight techniques have distinct advantages and disadvantages. Airplane flights can be much faster while helicopter flights are much more maneuverable. It all boils down to where the lift comes from and how it is created. If you were to try to hover a fixed wing airplane, there would be no air moving over the wings to create lift and it would fall to the ground.

I hope this helps.

Answer 2

The rotation of the rotor disc creates the lift required for hovering and flight in any direction, including backward. The airplane produces it's lift by forward motion through the air. If the plane is not moving at a given speed, the wing "stalls" and the plane falls. The rotor on a helicopter can stall as well, but only if the RPM droops or slows.
Trouble is, if you stall a helicopter, there is no recovery. You suddenly become a very expensive rock.

Answer 3

When in translational flight, not hovering but moving forward above about eighteen knots, the rotor system takes on the characteristics of a disc. Much like a frisbee. When you throw a frisbee, if it's spinning fast enough, it will move toward the direction it is tilted. The same happens in a helicopter rotor disc. The cyclic moves the swash plate which tilts the rotor in the desired direction of flight. To go forward, you apply forward pressure on the cyclic, the rotor plane tilts forward and off you go. If you were standing behind the helicopter when this happens, you'll feel the breeze as the aft thrust hits you.

Answer 4

Airplanes depend on forward motion to generate lift or the upward force that holds them up. This is accomplished by something called the Bernoulli principle. This priniciple essentially means that when you have air moving above and below an object that has a specific shape, the air on the top moves faster and thus creates a low pressure area and the air below it moves slower and creates a high pressure area. This shape is called an airfoil and is the typical cross section shape of an airplane wing.
For aircraft that have alternate means of generating upward force, this is not an issue. (example: Jumpjet or Harrier)
For those aircraft that have rotors that move such as helicopters, the motion of the rotor in a circle generates the upward force without forcing the entire craft to move forward.
It is actually a pretty simple concept that is applied in many different ways.

Answer 5

1) Usually airplanes have a efficiency around 10 or more, so the thrust is about 1/10 of the weight, so airplanes can't "hovering"
2) When the plane is not moving the control surfaces can't act, and the plane can't be controlled to keep the position.

But this is not due to the airplane itself, in fact some radio controlled airplanes can "hovering" there are a lot of videos
for exemple watch this video.(first)
There are also some full scale airplanes that can stay mid-air, for example X-31 (2nd and 3rd videos) or Su-37 because they have thrust to weight ratio higher than 1 and vectorized thrust.(and of course all VTOL aircrafts)

Answer 6

A helicopter uses a down thrust do create lift so by changing the angle of the blades you can move in different directions. An airplane use a fixed wing and motor the motor to create lift under the wing thus its only able to fly in one direction.

Answer 7

a harrier can do that but only becuase it can point the thrust from the engines down other wise an airplane needs air movment over the wings to create lift to stay in the air.the rotor blades on a helicopter produce lift that is pointed downward and can be angled left ,right, forward and backwards

Answer 8

If you can't imagine why a helicopter can hover and an airplane can't, and are calling helicopters "adorable little flying things" then may I highly suggest that you consider a different career path. Perhaps you would be better suited to a career in something less scientific, such as art.

Answer 9

Helicopters and planes dont fly the same way.... helocopters creat lift from the rotating wing, or blade. as a planes creat lift from air pasing over and under the wing. in helicopters the wing is always moving so it con hover, and an airplane has to be moving to have air pass over and under the wing...good luck with your flight training.

Answer 10

Totally different lift generating systems.

Airplanes depend upon forward motion to force air around the wings to generate lift.

Helicopters spin their wings through the air and therefore do not require forward motion to generate lift.