The reason why airplanes can fly, why airplanes can fly

Any aircraft must generate a lift force greater than its own gravity in order to fly into the air, which is the basic principle of aircraft flight.

I believe everyone has played with kites or bamboo dragonflies when they were children, these two small gadgets are very simple in structure, but they contain profound principles of flight. The wing of the airplane comprises two kinds of fixed-wing and rotary-wing, and the principle of the kite is somewhat similar to the glider, all rely on the upward lift force that is blown by the on-demand air flow, but there is a certain difference with the fixed-wing aircraft; However, gyroplanes and bamboo dragonflies have the same effect, both rely on the rotation of the rotor to produce upward lift.

How does the wing generate lift? Let's start with a little experiment: hold one end of a piece of white paper, the other end of the white paper will naturally hang down due to gravity, and now we will take the white paper to our mouth and blow in a horizontal direction to see what happens.

Ha, instead of being blown open, the hanging end of the paper floats up, what is the reason for this? The basic principle of fluid mechanics tells us that the atmospheric pressure of the slow flow is greater, and the atmospheric pressure of the fast flow is smaller, and the air on the white paper is blown and flows faster, and the pressure is smaller than the air that does not move under the white paper, so the white paper is held up.

For a fixed-wing aircraft, when it flies in the air at a certain speed, according to the principle of relative motion, the movement of the wing relative to the air can be seen as the wing is not moving, while the air flow flows through the wing at a certain velocity. Because the wing is generally asymmetrical, the upper surface is more convex, and the lower surface is relatively flat, which makes the air be divided into upper and lower strands when flowing through the wing, the air flowing through the upper surface is fast and the pressure is small, and the air flowing through the lower surface is slow and the pressure is large, which produces a pressure difference between the upper and lower wings, and the upward pressure is the lift of the aircraft, which drags the aircraft in the air.

Here's why airplanes can fly:

When the air of equal mass passes through the upper surface and the lower surface of the wing at the same time, different flow velocities will be formed above and below the wing, the flow velocity is large and the pressure is small when the air passes through the upper surface of the wing, and the flow velocity is small and the pressure is strong when passing through the lower surface, so that the aircraft will have an upward resultant force at this time, that is, the upward lift, due to the existence of lift, the aircraft can leave the ground and fly in the air.

Structural features of the aircraft

The fuselage is mainly used to carry personnel, cargo, fuel, ** and on-board equipment, and through it it will be the wings, tail, landing gear.

and other parts are connected into a whole. in light aircraft and fighters.

On strike aircraft, the engine is often installed in the fuselage.

The wing is the main component used to generate lift on the aircraft, which is generally divided into two wing surfaces, the front and rear of the wing are basically straight and the straight wing is called the straight wing, the leading edge and the trailing edge of the wing are swept backward called the swept wing, and the plane shape of the wing is triangular.

The former is suitable for low-speed aircraft, and the latter two are suitable for high-speed aircraft.

The vertical tail is vertically installed at the tail of the fuselage, and its main function is to maintain the directional balance and control of the aircraft.

Airplanes fly into the sky on the principle of aerodynamics.

Airplanes fly into the sky on the principle of aerodynamics, the main of which are two fluid theorems: the continuity theorem and Bernoulli's theorem. Most of the lift of the aircraft is generated by the wings, and the air flows to the leading edge of the wing, which is divided into two streams, upper and lower, which flow along the upper and lower surfaces of the wings respectively, and rejoin at the trailing edge of the wing and flow backwards.

The upper surface of the wing is relatively convex and the flow tube is thinner, indicating that the flow rate is increased and the pressure is reduced.

On the lower surface of the wing, the airflow is blocked, the flow tube becomes thicker, the flow rate slows down, and the pressure increases. As a result, there is a pressure difference between the upper and lower surfaces of the wing, and the sum of the pressure difference perpendicular to the direction of the relative airflow is the lift of the wing. With the help of the lift gained from the wings, the heavier-than-air aircraft overcomes its own gravity due to the Earth's gravity and soars into the blue sky.

How the plane landed

The landing of an airplane is similar to that of an airplane taking off. During landing, the aircraft needs to maintain sufficient lift while constantly decelerating to ensure that the aircraft can descend smoothly. When landing against headwinds, the aircraft can obtain the required lift at a lower speed, thereby reducing the relative velocity to the ground at the moment of grounding, thereby reducing the taxiing distance.

In order to achieve the same lift, the relative velocity of the aircraft to the ground is greater than when landing against the wind. This makes the speed of the flying pants machine at the moment of grounding larger, the gliding distance becomes longer, and the control is not good, which is easy to cause potential safety hazards.

In addition, the direction of the runway is fixed, but the direction of the wind changes frequently. Therefore, when the aircraft takes off and lands, it is not always headwind, and it is often carried out in crosswind conditions. Due to the slow speed and poor stability of the aircraft during take-off and landing, the aircraft may deflect in case of strong crosswinds, which increases the difficulty of the pilot's foolish behavior.