Why is the plane so heavy that it can fly?

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; The flow velocity is small and the pressure is strong when passing through the lower surface.

Therefore, at this time, the aircraft will have an upward resultant force, that is, an 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 opposite to lift, and it is subject to the gravitational pull of the earth.

The gravity of the force 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 amount of pulling force. In general, the engine outputs power.

The greater the force, the greater the thrust generated.

The faster the plane flies. 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.

Principle of Aircraft Flight:

1. The difference in pressure through which the air flow produces lift: the ascent of the aircraft is based on Bernoulli's principle.

That is, the greater the velocity of the fluid (including liquid and air), the lower its pressure; The smaller the flow velocity, the greater the pressure. When the aircraft flies, the streamline distribution of the air around the wing is different according to the shape of the cross-section of the wing, and the upper and lower streamlines are dense and the flow velocity is large, and the streamlines below are sparse and the flow velocity is small.

2. The shape of the wing of the aircraft can make the flow velocity under the wing lower than the flow rate above, resulting in the pressure difference between the upper and lower wings (that is, the pressure below is stronger than the pressure above), so there is a lift, and this pressure difference (or the magnitude of the lift) is related to the forward speed of the aircraft.

3. When the speed of the aircraft is greater, the pressure difference, that is, the lift, will also be greater. Therefore, the plane must take off at a high speed so that the plane can take to the sky. When the plane needs to descend, as long as it reduces the speed of its forward, its lift will naturally become smaller, less than the weight of the aircraft, and it will descend and land.

In two aspects, one is sufficient power, and the other is that the shape of the body meets the aerodynamic requirements. The former is the foundation, that is, the engine, and the latter is the prerequisite for achieving various flight performance. There is a saying that with enough power, even a brick can fly.

Now both turbofan engines and piston engines have enough power, and the shape of the aircraft is designed to meet those requirements, as stated in the upper floor.

I don't know if you have ever been on a plane? Every time I see a plane whizzing in the sky, I am always a little worried, the average civil airliner can carry 100 to 300 people, what if the plane can't bear so many people, what if it falls?

How did the plane fly when it was so heavy? After reading it, I have increased my knowledge again.

Airplanes are heavier-than-air aircraft, so they need to expend their own power to gain lift. And the ** of lift is the effect of air on the wing in flight.

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

Aircraft generally fly at an altitude between 8,000 and 12,000 meters:

Because this altitude is basically in the stratosphere, the flight resistance of the aircraft is low and fuel-efficient. Of course, the altitude of the aircraft is different for each route, and the altitude for take-off and landing is also uncertain.

More than 20,000 meters this is the limit, if the air density has been rising is too low, if you want to maintain lift, you can only speed up, but the air density is low and the oxygen content is low, if the engine is still burning, there is no force, and the thrust is not enough, it may be similar to the air intake of the internal combustion engine is not enough, and there is no deflagration of the kind of power, so it can't fly up to a certain height. The maximum flight altitude of different types of aircraft is different, military aircraft can reach 35,000 meters, and civil aircraft such as the common Boeing 737 are only 14,000 meters altitude.

The take-off and landing stages of civil airliners are in the troposphere, and in the stratosphere, they are both cruising stages and aircraft level flights. Because the ceiling of civil airliners is not high, and there is still a certain gap with fighter jets, civil airliners generally cruise at an altitude of about 10,000 meters.

The maximum take-off mass of an aircraft is determined by the engines of the aircraft, and currently the maximum take-off mass of the largest aircraft in the world is 640 tons.

The maximum take-off mass of an aircraft is the maximum weight that an aircraft can tolerate during take-off due to design or operational limitations. The maximum take-off weight is one of the three design weight limits for the aircraft, the other two being the maximum zero fuel weight and the maximum landing weight. The total weight of the aircraft is calculated before the flight.

The pilot calculates the required take-off speed of the aircraft based on the gross weight and ensures that the total weight is below the maximum take-off weight.

The principle of the take-off of an airplane

The aircraft must be able to generate a lift force greater than the gravitational force of the aircraft itself during take-off in order to lift the aircraft off the ground. Since the aircraft can only produce a limited lift, the total weight of the aircraft itself must be limited to ensure that it can take off from the ground normally.

In practical applications, the maximum take-off weight is also limited by other factors, such as runway length, atmospheric temperature, take-off plane pressure altitude and obstacle crossing ability. When determining the maximum approved take-off weight of a civil aircraft, it is necessary to meet certain airworthiness standards, which are generally measured under the international standard atmospheric conditions stipulated by the International Civil Aviation Organization.

Your question is actually asking about the flight principle of the airplane, and I will tell you the flight principle of the airplane, and you will be able to answer your question!

Newton's three laws of motion.

First Law: The velocity (v) of an object remains constant unless it is subjected to an external force.

There is no force, that is, the resultant force of all external forces is zero, when the plane keeps flying in a straight line at the same speed in the sky, the resultant force of the aircraft is zero, and the average person imagines that it is different from the imagination that when the plane lands to maintain the same sinking rate and declines, the resultant force of lift and gravity is still zero, and the lift force is not reduced, otherwise the plane will fall faster and faster.

The second law: The rate of change of momentum (p = mv) of an object with mass m is proportional to the applied force f and occurs in the direction of the force.

This is the famous f=ma formula, when the object is subjected to an external force, that is, an acceleration is produced in the direction of the external force, when the aircraft takes off and taxi, the engine thrust is greater than the drag, so the forward acceleration is generated, the speed is getting faster and faster, and the drag is getting bigger and bigger, sooner or later the engine thrust will be equal to the drag, so the acceleration is zero, the speed is no longer increasing, of course, the plane is already flying in the sky at this time.

The third law: The action force and the reaction force are equal in value and opposite in direction.

If you kick the door, your foot will hurt because the door also exerts the same amount of force on you.

Balance of forces. The force acting on the aircraft should be just balanced, if it is not balanced, the net force is not zero, according to Newton's second law will produce acceleration, in order to analyze the convenience of the force is divided into the balance of the three axes of x, y and z and the balance of the bending moment around the x, y and z axes.

The axial force imbalance will produce acceleration in the direction of the resultant force, the force of the aircraft in flight can be divided into lift, gravity, drag, thrust, lift is provided by the wing, thrust is provided by the engine, gravity is generated by gravity, drag is generated by air, we can decompose the force into two directions of force, called x and y direction Of course, there is also a z direction, but it is not very important to the aircraft, unless it is in a turn, when the aircraft flies in a straight line at equal velocity, the resistance in the x direction is opposite to the same thrust magnitude, so the net force in the x direction is zero, The speed of the aircraft is unchanged, and the lift in the Y direction is opposite to the gravity in the same direction, so the resultant force in the Y direction is also zero, and the aircraft does not take off and fall, so it will maintain a straight flight at the same velocity.

In the case of aircraft, the x-axis moment unbalanced aircraft will roll, the y-axis unbalanced aircraft will yaw, and the Z-axis unbalanced aircraft will pitch.

Then there's Bernoulli's law.

That's all for the simple aerodynamics, and now with the powerful aircraft engine, you can make the plane 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. According to the basic principles of fluid mechanics, the pressure of the atmosphere is greater than that of the slow flowing atmosphere, and the pressure of the fast flow is smaller, so that the pressure on the lower surface of the wing is higher than the pressure on the upper surface, in other words, the pressure exerted by the atmosphere on the lower surface of the wing (direction upward) is greater than the pressure applied to the upper surface of the wing (direction down), and the pressure difference between the two forms the lift force of the aircraft. When the wing of the aircraft is symmetrical and the airflow flows along the axis of symmetry of the wing, the airflow does not generate lift because the shape of the two surfaces of the wing is the same, so the airflow velocity is the same, and the pressure generated is the same.

But when a symmetrical wing moves through the air at a certain angle of inclination (known as the angle of attack or angle of attack), a similar flow phenomenon occurs with an asymmetrical wing, making the pressure on the upper and lower surfaces inconsistent, which also generates lift.

How did the plane fly when it was so heavy? After reading it, I have increased my knowledge again.

It is the principle of increasing lift of the airflow velocity used to hold the aircraft up.

So how can planes crash, not that the atmosphere is buoyant, but there are still so many planes crashing?

Quite simply, the airplane is subjected to the lifting force of the air, i.e., the lift.

Relying only on the wing curve, relying on the lift provided by Bernoulli's principle, can play a certain role, but secondary, at most, it can meet the cruise lift needs under good conditions, and it is difficult to explain the same speed, the difference between no-load and full-load lift requirements. This interpretation is also very dogmatic.

The main role is the angle of attack of the aircraft, which is defined as the angle between the wing chord and the incoming velocity, similar to the head-up angle in the vernacular, that is, when leaving the ground, the tail wing flips up, the wind resistance makes the nose of the aircraft lift, and the belly and the windward side are formed under the wings. There is also the extension and angle adjustment of the flap (that is, the part of the rear of the wing that can be retracted, which can be observed when you are on an airplane, and plays a great role in deceleration during take-off, turning, and deceleration). For example, the angle of attack of the no-load can be smaller, and the angle of attack of the full load can be larger.

You have to work hard to learn physics, let's put it simply:

An airplane is a heavier than air aircraft, and when an airplane flies in the air, it will produce aerodynamic forces acting on the airplane, and the airplane is lifted into the air by aerodynamic force. Before understanding the generation of lift and drag of aircraft, we also need to understand the characteristics of air flow, that is, the basic laws of air flow. Flowing air is airflow, a fluid, and here we will quote two fluid theorems:

Continuity Theorem and Bernoulli's Theorem:

The continuity theorem of fluids: When a fluid flows continuously and steadily through a pipe of varying thicknesses, the mass of the fluid flowing into any surface and the mass of the fluid flowing out from the other section is equal at the same time, since no part of the fluid in the pipe can be interrupted or squeezed up.

Bernoulli's theorem is to explain the relationship between velocity and pressure in the flow of a fluid.

The basic content of Bernoulli's theorem: when a fluid flows in a pipe, the pressure is small where the flow velocity is large, and the pressure is high where the flow velocity is small.

The vast majority of the lift of the aircraft is generated by the wings, the tail usually produces negative lift, and the lift generated by other parts of the aircraft is very small and generally not considered. As we can see from the diagram above, the air flows to the leading edge of the wing, divides into two streams, the upper and lower airflows, which flow along the upper and lower surfaces of the wing, 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 air flow is blocked, the flow tube becomes thicker, the flow velocity slows down, and the pressure increases. Here we refer to the above two theorems.

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. You can contact paper airplanes, bamboo dragonflies, etc. for understanding.

Why do airplanes fly at high altitudes? Despite the fit of the individual components, the main thing is that the aircraft has a pair of wings with a special cross-sectional shape. Wing profiles are also known as airfoils.

A typical airfoil is convex at the top and flat at the bottom, and is often referred to as streamlined. According to the continuity of the fluid and Bernoulli's theorem, the air flow through the upper surface is squeezed compared to the air far ahead, and the flow velocity accelerates and the pressure decreases, and even suction (negative pressure) is formed, and the flow velocity of the air flowing through the lower surface slows down. As a result, a pressure difference is formed between the upper and lower wing surfaces.

This pressure difference is aerodynamic. According to the law of force decomposition, it is broken down along the direction of flight into upward lift and backward resistance. The drag is overcome by the thrust provided by the engine.

The lift is just enough to overcome its own gravity and lift the aircraft into the air. That's why airplanes fly.