About 1500 Leonardo da Vinci has represented the project of the helicopter with the screw set in motion manually. Later other inventors have developed the flying models equipped with engines. But the first helicopters representing practical interest, have appeared only in 1930th years.
To be kept in air, it is necessary for planes to move forward. Wing movement through air creates the force opposite to force directed downwards of an attraction. Helicopters can hang in air, since. The carrying power is created at the expense of their rotation "ъЁ№ыіхт". The same as at planes, the carrying power is created by a stream of air which is bending around surfaces of a wing.
These narrow wings of the helicopter are called as blades. Rotation to the complete set of the blades named a rotor, is informed by the engine. And here at autofat the propeller moves a flying machine forward, and the stream of air arising thus forces a rotor to rotate, as a windmill. As well as at the helicopter, this rotation creates a necessary carrying power.
At lag of the helicopter the carrying power equals to its weight. That the helicopter gained height, the carrying power increase is reached by increase in a corner of a forward edge of blades in relation to a horizontal, named an angle of attack. For simultaneous increase in an angle of attack of all blades the pilot uses the lever named the modular switch of a step. At decrease the carrying power decreases by reduction of an angle of attack.
a movement Direction
At horizontal flight forward the rotor bends forward a little to provide a carrying power and to move the helicopter by air. For this purpose the angle of attack of each of blades increases, when they appear behind, and decreases - ahead. The rotor can bend and in other directions, forcing the helicopter to move back or to the parties. The pilot operates an inclination of a rotor by means of the lever of a cyclic step. When the hanging helicopter starts to move forward, it can bend on one side. It occurs because at the expense of air stream towards to the helicopter speed concerning air of the blade rotating forward while speed of the blade rotating back, decreases raises. Thus, the carrying power usually is more from one board of the helicopter and less - from another. For overcoming of this
Blade problems fasten on hinges that does by their more flexible and forces to be bent slightly up at rotation forward. It leads to reduction of a carrying power and counteracts its increase owing to increase of speed of blades concerning air. As a result the helicopter is not exposed to an undesirable inclination.
In flight odnorotornyj the helicopter tends to the slow reference round the vertical axis. It speaks Newton's third law: on any action there is an equal counteraction on force. Differently, when the helicopter informs force (action) to a rotor, rotating it, the rotor will inform in turn opposite directed force (counteraction) to the helicopter. As the helicopter is rather heavier, he will slowly address, however all the same it is necessary for rotating force to oppose other, compensating force.
The Majority of helicopters one basic rotor and the complete set of the small vertically located blades - protivovrashchatelnyj have a rotor. It provides horizontal rotating force which extinguishes a twisting moment owing to rotation of the basic rotor, thus, stabilising the helicopter.
Draught Change protivovrashchatelnogo a rotor provides change of a direction of movement. It is reached by change of an angle of attack of blades that reduces draught and allows the helicopter to turn in a direction opposite to rotation of the basic rotor. The increase in a corner and draught turns the helicopter in a direction of rotation of the basic rotor.
the Engine failure
In default the engine, the helicopter can be planted safely by means of the procedure named autorotation. The pilot lowers the modular switch of a step owing to what the edge of blades slightly tilts downwards. At decrease in the helicopter air which is bending around the blades, continues to rotate them in the necessary direction. When the helicopter comes nearer to the earth, the pilot again raises an edge of blades for maintenance of a carrying power, sufficient for decrease delay before landing.