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In this page, Lets see how do airplanes fly.
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Video of Explanation of How do airplanes fly?
As on today, airplane is the fastest vehicle (Fig 1) to transport humans and goods across the globe. Have you ever wondered how does it fly. Lets see.
Parts of an airplane
The important parts of an airplane are shown in Fig. 2. They are
- Body or fuselage
- Horizontal Tail
- Vertical tail
- Landing gear
Lift force of an airplane
In our world, if any object is free, it will try to reach the ground by moving downwards ( Fig. 3). This is because of the attractive force exerted by the ground which is called gravitational force. So when the airplane flies, there must be some force which acts against the gravitational force to make it float. That force is called lift force.
How lift is generated in airplane.
In airplane, wings are the primary lifting surfaces. The difference in pressure between upper and lower surfaces of the wing creates the lift force. The pressure on the upper surface is lesser than the pressure on the lower surface. The net force will act in the vertical direction (Fig. 4). This force is called lift. When the lift force is greater than the weight of the airplane, the airplane will float in the air or go upwards. The pressure difference is created by the flow of air over upper and lower surface of wing.
Thrust of an airplane
Now you know how the airplane is floating in the air. How does it move forward. Lets take an example of a bicycle. By pushing the pedal down you are giving a force which moves the bicycle forward. Similarly, the engines of the airplane provide a force to push the airplane forward. This force is called thrust of the airplane.
Drag of an airplane
Take the example of bicycle again. When you are going in a bicycle, when there is no wind, you would feel easier to push the bicycle. When there is a strong wind, you would feel difficult to pedal. It is because a force is acting against your movement. This force is called drag. Similarly, any object moving in the air will experience drag. The drag will act in the direction opposite to the movement of the airplane.
Major forces acting on the airplane
Now you know four major forces acting on the airplane (Fig. 5)
When the lift is greater than the weight, the airplane will float. When the thrust is greater than the drag, it will move forward. Now you know how the airplane flies.
Control surfaces of an airplane
To turn the airplane different control surfaces (Fig. 6) are used.
Pitching and yawing of an airplane
To turn up and down, which is called pitching of an airplane, the tail is used. When the control surface at the horizontal tail which is called elevator is deflected upwards, the airplane will pitch up. When the elevator is deflected down, the airplane will pitch down. Similarly, to turn left or right which is called yawing of an airplane, the control surface on the vertical tail which is called rudder is used. When the rudder is turned toward the right or starboard side, the airplane will turn toward right. When the rudder is deflected toward left or port side of the airplane, the airplane will turn left.
How does the airplane roll
The wing has control surface named ailerons on both left and right wings. When the ailerons are deflected in different direction on both the wings, the airplane will roll based on the deflection. When the aileron is deflected the lift generated by the wing will vary. If the aileron is deflected down, the lift will increase. When it is deflected up, the lift will decrease. With the asymmetric deflection of ailerons in both wings, the lift generated by both the wings will be different. That difference in lift induces a moment about the centerline of the airplane. Moment is nothing but the force multiplied by the distance. The net imbalance in moment will roll the airplane (Fig. 7). To roll in the opposite direction, the direction of aileron deflection should be reversed.
How the airplane is controlled
All the control surfaces are controlled by the pilot at the cockpit. Generally there will be a yoke, alternatively known as a control wheel or a control column along with a pair of pedals (Fig. 8). When the yoke is moved forward or backward, the airplane will pitch up or pitch down. When it is turned, the airplane will roll. When the right pedal is pressed, the airplane will turn toward right. When the left pedal is pressed, the airplane will turn toward the left.
Summary of How do airplanes fly
This is how the airplane flies. The lift is generated by the pressure difference and the thrust is generated by the engine. Both lift and thrust are used to overcome the weight and drag respectively. Different control surfaces such as aileron, rudder and elevator are used to control the airplane.
I hope this page is useful to you.
Thank you friend.
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Table of Contents
- Video of Explanation of How do airplanes fly?
- Parts of an airplane
- Lift force of an airplane
- How lift is generated in airplane.
- Thrust of an airplane
- Drag of an airplane
- Major forces acting on the airplane
- Control surfaces of an airplane
- Pitching and yawing of an airplane
- How does the airplane roll
- How the airplane is controlled
- Summary of How do airplanes fly