As long as you understand this equation, can you fly yourself?

The following article comes from WeChat public account: Original point reading, author Zhang Yuannan Zhangye

From ancient times to the present, how many people have imagined to insert wings, fight like eagles, and soar freely! However, it is the 20th century what really makes dreams real.

In 1903, two brothers, two bicycles repair workers in Donaldon, Ohio, the two brothers of Werba Leit and Oville Late, under extremely difficult conditions, they made a "flight" power aircraft. At 10:35 am on December 17th of this year, Oville Leat drove his "flight number", left the ground for 12 seconds in the air, and the flight distance was 120 feet. This historic flight announced that humans have begun to enter the era of wings and blue sky!

Wright brothers and plane invented

Today, large transport aircraft can send dozens of tons or even hundreds of tons of items to the blue sky, and the speed of flight can be several times the speed of the sound; the flying height can be as high as tens of thousands of meters; In any two places in the world. So, what amazing power helps humans to achieve a blue sky? This is an interesting and confusing issue.

Everyone knows that the reason why the birds fly are all because of a strong wings. The wings slap the air, which generates the upward force. The seeds of some plants in nature are completely another type. They have a "gliding device" that is more complete than human gliding machines.

The wing fruit of the cricket tree, under the action of wind, can fly with the objects heavier than itself

Readers must have played a toy called "Bamboo Dragonfly". This is a piece of bamboo -like bamboo -like bamboo sheet. The shape of the two -wing section is thick and thin, and a small stick of about 10 cm long is fixed in the middle. When playing, pinching the stick on the palm of the two hands and rubbed it hard, so that the bamboo slices on the top rotated quickly. Then suddenly let go, "Bamboo Dragonfly" rose into the air, rising and higher, until the final rotation became slower, and immediately lost balance and dragged down!

"Bamboo Dragonfly" can rise into the air because when the propeller -like wings are rotating, a lift will be generated to take itself over the sky. This magical lift is formed because of the asymmetry of the wings of the "bamboo dragonfly" wings.

"Bamboo Dragonfly" section of a wing

When the wings are rotating, the airflow flows through and below the wing surface at the same time. The airflow flowing through the lower wing surface has not changed the front and rear speeds, and the airflow flowing through the upper wing surface is because the bulge part makes the pathway of the gas narrowed, so the speed of the airflow becomes larger. According to the principle of Bynuli of the fluid movement, the corresponding pressure with a large speed and the corresponding pressure of small speed. That is to say, the pressure on the wing surface is greater than the pressure of the upper wing surface. The difference in pressure of the upper and lower wings is exactly the origin of the "bamboo dragonfly" lift.

However, while the wings of the sports are lift, they are also resistant to air. The size of the resistance is closely related to the wing shape!

The following extremely interesting experiments can help readers understand this deeper. People can easily blow the candle flame in front of them, and even blow it out. But not everyone can make the candle flames in front of them! Maybe this will make you feel incredible, but the fact is completely possible. The figure below will tell you how to achieve this.

The test method is to put a square card between the mouth and the candle flame. The test result is that the more you blow your breath, the more obvious the candle flame floats to you! Readers can try it if you don't believe it!

The above experiments show that square cards not only hinder the movement of the forward airflow, but also generate a reverse braking force. If we do not put a square card between the mouth and the candle flame in the experiment, but the streamlined object like a fish shape, the air will flow forward as if not hindered.

The picture below is another experiment. In the middle is an approximate streamlined hindrance made of paper, and the blunt side faces you. How do you blow your breath now, candle flames can only be drifting forward!

Below we return to the question of "Flying". To realize the wings and blue sky, first need a good wing. And a good wing must meet at least two requirements: one is to generate sufficient lift, and the other is a streamlined outer body.

However, how can I do it all? On the journey to the blue sky, human beings must thank the "Father of Russia" Rockevsky's performance.

Nicholas Rockevsky (ииколай җуковский, 1847-1921) graduated from the Department of Applied Mathematics at the University of Moscow. He has a profound knowledge, versatile, and has a deep accomplishment in aviation.

Rockevsky

During the Rockevsky era, the gliding machine test had just begun, and everything was explored in practice. At that time, many scientists believed that flight could only seek truth from the failure again and again!

Rockevsky believes that a flight theory must be established. He devoted himself to the research of gas winding and tirelessly explored for decades. In 1906, he successfully resolved the main topics of aerodynamics, founded the principle of wing lift, and found a method of designing excellent wings. He was ingenious and introduced a function with multiple (z = x+yi) as an independent variable.

This function can transform one graphic of the z plane to another graphic of the plane of w (ω = u+vi).Rockevsky proves that on the Z plane, the circular circle of the round A and -A is cut, and through the transformation, it will become an aircraft wing-shaped section on the plane.This proof provides information for designing a variety of excellent wings, avoiding practical blindness!There are many results in the life of Rockevsky. The papers such as "About Flight Theory" published by 1890-1891 predicted the possibility of turning over the fight during flight.

In 1906, when Johovsky's foundation papers "On the Connection of Evil flow" was published, his prophecy was realized!A Lieutenant Russian Army Lieutenant Nest Chelov completed the first stunt performance of the world's "flipping" in the world.

In 1921, Lenin issued an order to recognize Rockevsky's great achievements in the aviation industry, respecting him as "the Father of Russian Airlines".

This article is authorized to reprint from WeChat public account: Original Reading (ID: Tupydream), author Zhang Yuannan Zhang Ye

Reprinted content only represents the author's point of view

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It does not represent the high energy office of the Chinese Academy of Sciences

Edit: 3C 273

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