Why do kites fly into the sky? What is the principle?

Principle: As we all know, there are two necessary conditions for a kite to fly:

1. The kite must be in windy weather before the kite can fly.

2. Kites must be pulled by strings. A "kite with broken strings" will definitely fall off after a short period of drifting away.

Generation of lift force: The kite is affected by the wind in the air because the air will be divided into upper and lower flow layers. The air passing through the lower layer of the kite is blocked by the kite surface, and the air flow speed decreases and the air pressure increases; the air in the upper layer circulates smoothly and the flow speed increases, causing the air pressure to decrease; the lift is generated by this difference in air pressure, which is why The reason why a kite can rise.

As can be seen from the above, there are two factors in the generation of lifting force: wind force and traction force. The direction of the wind force is basically horizontal, and the angle at which the kite is affected by the wind and the magnitude of the upward force can be easily controlled by lifting the string. After several practices, kite flyers will quickly master the skills of controlling the kite: when flying a kite, they usually pump and release the kite.

When pulling, because the kite string is usually placed on the upper part of the kite surface, increasing the traction force can control the kite angle to become smaller, the upward force increases, and the kite rises steadily; when flying, it is balanced. The traction force of the kite becomes smaller. Under the combined effect of wind force and lifting force, the kite will fly high and far away, but it must be pumped again quickly to keep the kite's angle stable again. When the wind is strong, you can put out more lines, and when the wind drops slightly, you can take in some lines.

Extended information:

In 1600 AD, Eastern kites were introduced to Europe by the Dutch. In the 19th century, British inventor Clay invented the glider inspired by kites. Texas actor "Captain Cody" once used a kite to drag a folding boat across the English Channel;

Continuing his efforts in 1901, he flew on a twin box kite, which attracted great interest from the British Army. . Soon, airplanes replaced military kites. In 1970, the U.S. space program designed various "flying wings", making kites once again a toy for adults, such as the Rogloro folding flying wing, which was originally designed for the safe landing of the Mercury spacecraft capsule and was later adopted. Parachutes replaced;

But this folding wing became the wing of today's hang glider. Kites provided the principle and inspiration for airplanes to fly into the sky and became the ancestor of mankind's dream of flying into the sky.

Baidu Encyclopedia - Kite flying (traditional Chinese folk customs and activities)

Ifeng.com - The dream of a kite