How does an airplane take off? Why can it fly smoothly at high altitude?

After thousands of years of human dream, after continuous practice, it finally came true more than 100 years ago. So what exactly is the principle of an airplane that can fly in the sky?

In fact, the principle is not complicated, since the invention of the glider.

After that, after many years of practice and hard work, an airplane with a power plant was finally invented, and an airplane that could be maneuvered. The airplane is made up of the fuselage, wings.

Tail, power plant and landing gear.

The principle of take-off is mainly based on the wing and power plant (mainly the engine). The take-off of the aircraft is mainly the thrust provided by the power plant, such as when the plane is taxiing on the runway and preparing to take off, the air will flow through the wings, and then divide into two streams of air, then the air flow will produce pressure on the wings, and when the pressure under the wings is greater than the pressure above, then lift will be generated.

At the airport, we have all seen planes driving at high speed on the runway when they are ready to take off. So why is it driving at high speeds? In fact, the faster the plane runs on the runway, the faster the flow of air will be, and the greater the lift.

When the lift is high enough, the plane will leave the ground and slowly fly into the sky. However, the engines of the aircraft must constantly provide power to propel the aircraft forward, otherwise it will fall off.

Airplanes fly by lift. The difference between the lower wing gas pressure value and the upper wing gas pressure value is the lift.

The wings of a bird are afraid of hitting the air, and the flexible shape of the wings is used to change the impedance (reaction force) generated by the air.

And to reach the direction of flight. At the same time, the wings play the role of slowing down the gravity of the body (gliding).

The aircraft takes off and continuously accumulates force to slow down the gravity of the fuselage and fall directly to achieve the final effect of take-off, and at the same time, the wings change the airflow period to the angle and altitude of the aircraft. The decisive factor for the aircraft to fly is the thrust and pull force generated by the engine, the wing only slows down the gravity of the fall and balances the gravity of the aircraft, and at the same time plays a role in the resistance of the wing to the air to change the direction of the aircraft's power.

In fact, it is the use of updrafts to propulse, and some of its own power engines. Because the air is interactive, there will be some aerodynamic forces.

The principle is fluid dynamics, which is based on the pressure in the air, and some buoyancy in the air. Because this is all calculated and the plane can gain a lift, it can run smoothly at high altitudes.

The main thing is that the wings will have lift during the ascent process, so the plane will take off. Because at high altitude, the wings have a certain balance ability, so they can fly smoothly.

First, inertia converts kinetic energy into potential energy until the potential energy and kinetic energy are balanced; Second, the air convection produces a lifting force that breaks the balance, making the lifting force bigger and bigger, that is, the potential energy is getting bigger and bigger, until the plane takes off. For example, the process of an airplane taxiing and taking off on the runway is a process of potential energy equal to kinetic energy plus lifting force and balance.

Junior high school physics has a detailed explanation of fluid pressure! When the airplane is fast enough, the air velocity difference will form between the upper and lower wings, and the pressure difference between the upper and lower wings will act on the wings to produce a lift! The lift is large enough and the plane takes off!

There is a difference in air velocity between the upper and lower wings, which causes the aircraft to generate lift, hydrodynamics, go and see!

It's very complex, to be precise, some aerodynamics, generating an upward force.

The airplane mainly uses the upper and lower surface areas of the wings to flow air at different speeds, resulting in pressure differences. The use of pressure difference to make the aircraft float in the air is the principle of fixed-wing aircraft take-off.

The take-off principle of the aircraft relies on the engine backjet take-off.

The principle of the take-off of the plane:

In the take-off stage of the aircraft, the wings of the aircraft will show a certain elevation angle, which makes the aircraft in the process of taxiing, the air above the wings mostly flows downward, so that the air velocity above will decrease, and the flow rate of the air below will increase, under the action of two forces, the aircraft has an upward lift.

When the pressure ratio between the upper and lower wings reaches an optimal point, coupled with the fact that the aircraft itself also has engines to provide thrust, the two can fly as soon as they are combined, and the air flow rate will change according to the speed of the aircraft, so the faster the aircraft, the greater the lift the aircraft gets, and the higher it will naturally fly.

Notes:

During the flight of the aircraft in the air, the three tail fins need to play a role in controlling the direction, and they can all change the aerodynamic force by changing the angle, so when the aircraft has a change of direction operation, these tails will change with it.

The plane also needs air to provide lift when it lands, which is also to avoid the plane from falling. However, at this time, the wing will raise a baffle, which can block part of the air from circulating upward, so that the lift force slowly supports the aircraft, and combines with the aircraft power plant to achieve a safe landing.

Categories: Education Science >> Science & Technology >> Engineering Technology Science.

Problem description: Does an airplane generate a lot of heat when it is in the air?

Analysis: The side profile of the wing is a shape in which the upper edge is arched upwards and the lower edge is basically straight. As a result, the liquid is blown through the upper and lower surfaces of the wing and from the front to the rear at the same time, and the air flow from the upper edge is faster than that of the lower edge (because the upper edge has a large arc and a longer arc length, which means that the distance is longer).

According to the Bernoulli equation of physics, the same fluid flowing through a certain surface has less pressure on the surface at a faster speed. Therefore, it is concluded that the atmospheric pressure on the upper surface of the wing is smaller than that on the lower surface, so that the lift force is generated, and the lift force reaches a certain level, and the aircraft can lift off the ground.

There's a formula that I don't know if you've ever seen: l cl*1 2* *v*v*s.

Its significance is that the lift of an aircraft is the product of the following five quantities:

1.The lift coefficient cl (that c represents the coefficient, l is the corner code, I don't have a character tool can not type), its value is related to many fine variables such as the windward angle of the aircraft, generally in a few tenths, the details are not very affectionate: (

2.One in two is.

3.Atmospheric density (the environment in which the aircraft is located, which can be high or low altitude).

4.The square v*v of the airplane relative to the velocity of the surrounding atmosphere (it can only be expressed as this without a corner code).

5.Wing area s

This formula is only suitable for relatively slow flights, just like the common large and small passenger planes with orange flights, other aircraft (as long as the wings) speed does not exceed Mach 1 can basically be used, but like the fighter that of two or three Mach high-speed flight is not good, if the speed is too large, the air on the surface of the wing of Xiaowuwu will become viscous, to take into account the Reynolds number, at that time there is another formula, very complicated, I don't understand. ：）

I work in a civil aviation company, so the answer should be relatively correct. Hope it helps. ：）

The main forces acting on the aircraft in flight are lift, gravity, pull and drag. Lift causes the aircraft to leave the ground and fly through the air. The direction of gravity is the opposite of lift, which is a downward force that is generated by the gravitational pull of the earth.

The pulling force causes the aircraft to fly forward in the air, and the aircraft is hindered by the air during the flight, which forms a drag force and limits the flight speed of the aircraft. Airplanes are based on the principle of balance of lift and gravity to be able to fly in the air for a long time.

Most aircraft are mainly composed of organisms, landing gear, power plant, flight control systems, on-board equipment, and other systems, including wings, fuselage, and tail. The main forces acting on the aircraft in flight are lift, gravity, pull and drag.

One of the key points why airplanes can take to the skies is the special structure of the wings. The cross-section of the wing of an aircraft is generally rounded and blunt at the front and sharp at the rear, with an arched upper surface and a flat lower surface. When equal mass air passes through both the upper and lower surfaces of the wing, different flow velocities are formed above and below the wing.

The velocity of air passing through the upper surface of the wing is high and the pressure is small; When passing through the lower surface, the flow velocity is small and the pressure is strong, so the aircraft will have an upward resultant force, that is, the upward lift, due to the existence of lift, so that the aircraft can leave the ground and fly in the air. The faster the aircraft flies and the larger the wing area, the greater the lift generated.

The direction of gravity is the opposite of lift, it is a downward force caused by the gravitational pull of the earth, and the magnitude of gravity is affected by the weight of the aircraft itself and the amount of fuel it carries. The pulling force causes the aircraft to fly forward in the air, and the power of the engine determines the size of the pulling force. In general, the greater the output power of the cavity engine, the greater the thrust generated, and the faster the aircraft can fly.

When the aircraft is in the air, it is hindered by atmospheric molecules in the air, and this obstacle forms a drag force that is opposite to the direction of the pulling force, limiting the flight speed of the aircraft.

We all know that if you throw a stone upwards, it will fall even if it is thrown high. This is because the stone starts with a lot of upward force, but then it is affected by gravity, so it will eventually fall. When the stone rises to the highest point, the lifting force and the descending force reach a balance, and the aircraft is also based on the principle of balance between the lifting force and gravity, so that the aircraft can fly in the air for a long time.