How was the helicopter invented? 10

Bamboo dragonfly in China.

China's bamboo dragonfly and the Italian Leonardo da Vinci's sketches provide inspiration for modern inventions and point out the correct direction of thinking, and they are recognized as the starting point of the development history.

The bamboo dragonfly, also known as the flying spiral and the "Chinese spinning top", is a peculiar invention of our ancestors. Some believe that China had bamboo dragonflies as early as 400 BC, and another more conservative estimate is that it was in the Ming Dynasty (around 1400 AD). This folk toy called bamboo dragonfly has been handed down to the present.

Although modern *** is ten million times more complex than the bamboo dragonfly, its flight principle is similar to that of the bamboo dragonfly. The modern rotor is like the blade of a bamboo dragonfly, the rotor shaft is like the thin bamboo stick of the bamboo dragonfly, and the engine that drives the rotor is like the hands of the bamboo stick that we rub hard. The blades of the bamboo dragonfly are round and blunt in the front and sharp in the back, the upper surface is relatively rounded, and the lower surface is relatively straight.

When the air flow passes over the upper surface of the round arch, its flow velocity is fast and the pressure is small; When the air flow passes over a straight lower surface, its flow velocity is slow and the pressure is high. As a result, a pressure difference is formed between the upper and lower surfaces, and an upward lift force is generated. When the lift force is greater than its own weight, the bamboo dragonfly will take off into the air.

The principle of the rotor generating lift is the same as that of the bamboo dragonfly.

The Encyclopædia Britannica records that this "*** toy" called "Chinese spinning top" was introduced to Europe in the middle of the 15th century, that is, before Leonardo da Vinci drew the design of *** with screw rotors.

Volume 9 of the Concise Encyclopædia Britannica reads: "*** was one of the earliest ideas of human flight, and for many years it has been believed that the first person to propose this idea was Da? Vinci, but now it is known that the Chinese made *** toys earlier than the Europeans of the Middle Ages. ”

Painting by Leonardo da Vinci, Italy.

The Italian Leonardo da Vinci proposed the idea and sketched it in 1483.

At the end of the 19th century, an imaginary picture of Leonardo da Vinci painted in 1475 was found in the Milan Library in Italy. It is a huge spiral made of sizing linen that looks like a giant screw. It rotates with a spring as the power force, and when it reaches a certain speed, it carries the body into the air.

The driver stands on the chassis and pulls the wire rope to change the direction of flight. Westerners say that this is the earliest blueprint.

It was invented based on the bamboo dragonfly of Doraemon

Principle of direct bai helicopter take-off:

The engine drives the rotor to provide lift, lifting the power in the air, the main engine returns to the small propeller at the tail at the same time, and the airborne gyroscope can detect the rotation angle and feedback to the small propeller, and the reaction force at different speeds generated by the large propeller can be offset by adjusting the pitch of the small propeller.

It is mainly composed of the fuselage and lift (including rotor and tail rotor), power, transmission and airborne flight equipment. The rotor is generally driven by a turboshaft engine or piston engine through a mechanical transmission system composed of a propeller shaft and a reducer, and can also be driven by the reaction force generated by the jet at the tip of the propeller.

The maximum speed can reach more than 300km h, the diving limit speed is nearly 400km h, the practical ceiling can reach 6000 meters (the world record is 12450m), and the general range can reach about 600 800km. The transfer range of the internal and external auxiliary fuel tanks of the aircraft can reach more than 2000km. There are different take-off weights according to different needs.

The largest heavy *** currently in service in the world is the Russian Mi-26 (with a maximum take-off weight of up to 56t and a payload of 20t). At present, the practical application is mechanically driven single-rotor and dual-rotor, of which the single rotor is the most numerous.

In essence, it is another kind of aircraft that is different from the aircraft, and its thrust, lift and maneuvering are relatively large and far from the aircraft.

1. Bats and radar.

Bats emit a kind of ultrasound wave that comes back when it encounters an object, but humans can't hear it. Radar was invented based on this property of bats. Radar is used in a variety of places, such as airplanes, aviation, etc.

2. The downwind ears of jellyfish.

In nature, jellyfish have been living in seawater for more than 500 million years. But what does a jellyfish have to do with a downwind ear? Because jellyfish swim to the sea in droves before the storm comes, it is a sign that the storm is coming.

But what does this have to do with "downwind ears"?

It turns out that on the blue ocean, the infrasound waves (frequency 8 13 Hz) created by the friction of air and waves are the foreshadowing of the storm. This kind of infrasound is inaudible to the human ear, but it is easy for jellyfish. Scientists have found that jellyfish have a thin stalk in their ears, a small ball on the handle, and a small listening stone inside the ball.

Scientists imitated the structure and function of jellyfish ears, and designed the jellyfish ear storm instrument, which quite accurately simulated the organs of jellyfish that sense infrasound waves.

3. Thin-shell buildings.

The eggshell is arched in shape, has a large span, and includes many mechanical principles. Although it is only 2 mm thick, it is difficult to break it by smashing it with a hammer. Architects imitated it for the design of the thin-shell building.

This type of building has many advantages: less material, large spans, and durability. Not all of the thin-shell buildings are arched, and the world-famous Sydney Opera House resembles a group of sails in harbour.

4. Zebra. Zebras live on the African continent and look no different from ordinary horses, with stripes on their bodies being a protective color derived from their environment. Of all the zebras, the fine zebra is the largest and most beautiful.

It is 140-160 cm tall at the shoulders, and its ears are round and large, with fine and numerous stripes. Zebras often live with wildebeest, whirlhorned oryx, gazelles and ostriches in the grasslands to ward off predators. The application of zebra stripes to the military is a very successful example of biomimicry.

5. Dragonflies and biomimicry.

The dragonfly vibrates through its wings to create locally unstable air currents that are different from the surrounding atmosphere, and uses the vortices created by the air currents to make itself rise. The Dragonfly can soar with very little thrust and can fly not only forward, but also backward and left and right, and can fly forward at speeds of up to 72 km/h. In addition, the dragon's flight behavior is simple, relying on only two pairs of wings to flap constantly.

Scientists have successfully developed a helicopter based on this structural basis. When flying at high speed, the aircraft often causes violent vibrations, and sometimes even breaks the wings and causes plane crashes. The dragonfly relied on its weighted wing moles to fly at high speeds, so people followed the example of dragonflies and added counterweights to the wings of the plane, and the solution solved the thorny problem of vibrations caused by high-speed flight.

The development originated from the bamboo dragonfly in China: two pieces of bamboo cut into uneven thickness are placed on a wooden stick, and the bamboo pieces can fly into the sky using inertia and air pressure as a power with both hands. We used the bamboo dragonfly as a toy and didn't take a step further.

However, Europe has groped for the "bamboo dragonfly principle" and created ***.

In 1936, the Germans created an engine-driven ***, which can last for 2 hours and 20 minutes, reach an altitude of three or four hundred meters, and can also hover, turn 360 degrees, fly forward, backward, fly sideways and other complex actions.

In 1936, the Russian-Americans successfully developed the first military ***. Three years later, a batch entered service in the US Army.

Or the Germans were the first to install a machine gun on ***, which was used in combat in 1944. This is where the armament *** is attached.

Now the military *** has become a family of its own, they have anti-tank ***, fire support ***, destroyer ***, anti-ship ***, anti-submarine ***, land and sea *** and so on, this is a special type. There are also multi-purpose types, in addition to attacks, they can also be used for transportation, airborne, ambulance and other purposes.

The first practical helicopter: On September 14, 1939, the American aircraft engineer Igor Ivanovich Sikorsky completed the world's first recognized practical ***VS-300***, and its single-rotor with tail rotor *** configuration became the most common *** configuration now.

First prototype: August 1907, Frenchman Paul. A.T. Kearney developed a full-size manned aircraft and successfully flew it on November 13 of the same year.

This *** is known as "the first *** of mankind". Although it can't be called a complete ***, it has opened up a new field of aircraft.

The first test flight was successful***: in 1938, the German Hannareich piloted a twin-rotor *** for a perfect flight performance. This *** is considered by the *** industry to be the world's first successful test flight.

The first practical *** recognized in the world was done by Russian-American aircraft engineer Igor Ivanovich Sikorsky. On September 14, 1939, the famous *** aircraft designer, known as the father of modern ***, flew the VS300*** of his own design for the first time.