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A helicopter with two screws
A helicopter with two screws

A helicopter with two screws


Among the many helicopters schemes developed up to now, common circuit with two concentrically arranged rotors, which was first applied M. AT. Lomonosov in his "aerodromic typewriter." Both rotors are located in the circuit on the same axis, one above the other. upper screw shaft thus runs inside the hollow shaft of the lower screw. The screws rotate in opposite directions, so the fuselage reactive torque transmitted two mutually balancing each other. Helicopters constructed under this scheme have good maneuverability.

In particular, by changing the angles of the blades of one of the screws in comparison with mounting angles of the blades of another propeller (differential change in the overall pitch propellers) achieved by the difference in their reaction torque, which is being transferred to the fuselage, the helicopter rotates in one direction or another. The longitudinal and lateral control and management of the rise and descent will be described below. Now, we note only that the principles of such management are the same for most helicopters.


A helicopter with two screws 2

A helicopter with two screws


The Russian helicopter has been built under this scheme is still in 1907, the designer of the Antonov. Subsequently, the scheme used in many countries. Modern helicopter design II. I. Kamov also designed for twin-screw coaxial scheme.

The main advantages of helicopters, built under this scheme are its small size and light weight. This is achieved by the absence of the long tail boom to the tail rotor installation n long shafts to transmit torque from the motor to the screw, as the screws are mounted on a vertical axis next mail.

It is interesting to note that all helicopters weighing up to 800 kg built on the twin-screw coaxial scheme. It is possible that the helicopters will be in the near future, widespread use of individual aircraft.

This scheme, like any other, is not without drawbacks. Thus, due to the fact that the lower screw runs in a stream of air, thrown and twisted the upper screw, deteriorating conditions of work and difficult calculation in the design of the screw.

Helicopter with two longitudinally spaced rotors

Driving a helicopter with a longitudinally arranged rotors was first proposed NI Sorokin. According to this scheme, one screw located above the forward fuselage, and the second - on the tail. Both screws can be driven into rotation by one or two motors. Screw rotational direction opposite to the mutual settlement of reactive moments.


Helicopter rotors with two

Helicopter rotors with two


This scheme is beneficial to build a heavy multi-seat helicopter, as the fuselage of the helicopter is a convenient location for freight and passengers, and, in addition, a helicopter of this scheme has good longitudinal control and allows a significant change in center of gravity along the axis of the fuselage. For example, if the helicopter will drop the nose, that is. e. the center of gravity moved forward, it will create a diving point that could easily be eliminated increasing traction nose screw with a corresponding reduction of thrust screws installed in the tail. If you move the center of gravity paza- we will have to increase traction screws installed in the tail, and reduce cravings nose screw.

Advantage helicopter constructed according to this scheme is that it has a small cross-section of the fuselage, and therefore, low resistance to harmful, allowing fly with the greatest speed.


Helicopter rotors with two


Lack helicopter constructed according to this scheme is that the screw at the rear of the helicopter forward flight running in the air pre-perturbed forward screw, which reduces its efficiency.

Shown model helicopter with two longitudinally extending screws. Rotor blades for easier storage hangar can be made folding above the fuselage, which greatly reduces the size of the helicopter.


A helicopter with two rotors 23

Helicopter rotors with two


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