Why can kites fly into the sky? Why can kites fly into the sky

A kite is a kind of flying machine that uses air as a power force, usually pasted with paper or silk on a skeleton such as bamboo strips, pulled by a long thread tied to it, and released into the sky with the wind. In fact, there is no need to be surprised at all, an airplane heavier than a kite can fly, let alone a kite. So how did the plane fly?

This requires mentioning a law, Bernoulli's law: in a stream of water or air, if the velocity of the fluid is small, the pressure is greater, and if the velocity is large, then the pressure is smaller. This principle is derived from the conservation of mechanical energy, so it is only suitable for ideal fluids with negligible viscosity and non-compressibility.

The kite must be pulled by the string to fly, and as for the kite with a broken string, we know that it can't fly far. Therefore, the kite is able to maintain its balance in the air under the combined action of the wind, the traction force and the lifting force mentioned earlier. So let's talk about the force of the kite in the air.

In the air, we assume that the direction of the wind is basically horizontal, and the angle of the wind force on the kite, as well as the amount of upward force, is controlled by the string of the kite. If we increase the traction force, that is, the force acting on the lifting line, we can make the windward angle of the kite tend to 45°, then the lifting force will increase, and the kite will fly high; When we reduce the traction, the kite will fly higher and farther under the combined force of the wind and the lifting force, but we must quickly increase the traction force to keep the angle of the kite stable again and bring it to a balanced state. Therefore, when the wind is strong, the line is released, and when the wind is low, the line is retracted, so that the kite will always fly in the air.

The principle of the kite lifting into the air is mainly to rely on the thrust (of the wind) to lift in the air. The kite itself has weight and will fall to the ground, and the reason why it can float and fly in the air is that it is supported upward by the force of the air, which is called Yangli. When the kite is in the air, the air will be divided into the upper and lower stratospheres, at this time, the air through the lower layer of the kite is blocked by the kite surface, the flow rate of the air decreases, the air pressure increases, the kite rises, the air circulation of the upper layer is comfortable, the flow rate increases, the air pressure decreases, the kite is sucked up, and the lifting force is generated by the difference in air pressure.

Therefore, the kite flying in the air, in addition to receiving the lifting force of the air, is also subject to the pressure of the air pressing downward, this pressure is called resistance, if the resistance is less than the lifting force, the kite can fly in the air, so if the angle of the kite string is placed below, the resistance is enhanced, the kite will only fly far away, if placed above, the lifting force will be enhanced, the resistance will be reduced, and the kite will fly to a high place. <>

The kite always goes up against the wind, and the "body" of the kite is always diagonally downward, which is the key to the kite being able to fly into the sky. The kite always flies against the wind, and when the wind blows on the kite, it will exert a pressure on the kite, and this pressure is perpendicular to the surface of the kite. Because the kite is diagonally downward, the pressure on it from the oncoming wind is diagonally upward.

The weight of the kite is very light, and this upward pressure of the air is enough to send the kite into the blue sky. When the wind is very small, the kite flyer often runs with the kite string in the wind, or stands in place and constantly pulls the kite string, and uses the string to adjust the angle of the kite facing downward, which is to increase the upward pressure of the air on the kite and make the kite fly higher.

The reason why kites can fly is because of the lifting force. The kite is affected by the wind in the air, and the air through the lower layer of the kite is blocked by the kite surface, the flow rate of the air decreases, the air pressure increases, the air circulation in the upper layer is comfortable, the flow rate increases, the air pressure decreases, and the lifting force is generated by this air pressure difference, which is the reason why the kite can fly.

It is necessary for the kite to fly into the sky.

Kites can only be flown in windy weather, with the exception of the Coilhawk Kite.

Kites need to be pulled by a string, and a "kite with a broken string" will inevitably fall off after a short drift.

The kite is exposed to the wind in the air, and the air is divided into upper and lower layers. The air passing through the lower layer of the air slag slag kite is blocked by the kite surface, and the air velocity decreases and the air pressure increases. The air circulation in the upper layer is comfortable, and the flow velocity is enhanced, resulting in a decrease in air pressure; The lifting force is generated by this difference in air pressure, which is why the kite can rise.

In addition to silk and paper, the kite is also made of plastic. The bone poles are made of bamboo strips, wood and glue sticks. Someone designed a boneless kite, which is structured by introducing air into a silk wind pit, so that the kite forms a gently floating air pillow, and then rides the wind up.

The principle is that any object that flies in the air by aerodynamic force relies on a variety of physical forces, including buoyancy, gravity, and thrust, each of which has multiple causes.

The force of gravity, the pull of the kite string, and the thrust of the wind. The mutual pull of these three forces determines whether the kite takes off or lands, the gravity force is vertically downward, and the pulling force can be decomposed into two forces in the horizontal and vertical directions, and the pulling force in the vertical direction is still downward.

For the kite to fly and disturb him, it also needs to use the upward thrust of the wind. Therefore, kite flying must use the wind to slow down and the wind cannot be too small, and it needs to support its own gravity and part of the pulling force.