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Haraktristika sleeve helicopter rotor

Haraktristika sleeve helicopter rotor

Rotor hub (VNV) consist of a body and suspension arms hinged blades. Perfection VNV largely depends on how well chosen its main parameters. Among these parameters for the hinge screws primarily include:

  • - spacing of horizontal and vertical hinges;

  • - parameters characterizing the kinematics of HB, i.e. determining the nature of changes in the true angle of installation of the blade from the angles of deviation of the blade in the plane of the stroke, rotation H, and the coefficient of the stroke compensator k, cf = / ((3, £, k);

  • - parameters characterizing the loading of the bearing units of the sleeve;

  • - parameters that determine the damping moment relative to the vertical hinge (Bill) Mg ~ fg, £,).

Helicopter rotor, depending on how they carried the blade flapping deviation plane can be divided into three main types:

  • - with horizontal hinges (GSH) (2.4.1, a-d);

  • - with elastic elements that perform the role of GSH (2.4.1, e, g);

  • - without GSH or the elastic elements replacing them (2.4.1, h).

In the latter case the required compliance is achieved by selection of appropriate stiffness characteristics of the butt of the blade and the hinge axis (OR) of the sleeve.

Changing the angle of blade setting mostly at the expense of its rotation in the OR. In some type of the second OR HB is absent, and changing the installation angle of the blade due to twisting of the elastic member.

In practice, helicopter firm uses kinematics bushing with a different arrangement of joints with respect to the rotation axis of HB. Various combinations of hinges achieved a number of specific problems of the dynamics and nature of HB load bearing hinge joints.

Increasing the separation of the GS increases the control efficiency and the allowable range of the helicopter's centering, but the bending moments on the shaft of the main reducer are increasing. From the experience of domestic helicopter industry, it follows that it is advisable to have a minimum separation of GSh, and the necessary control stocks should be obtained by appropriate selection of the deviation range of the swashplate (AP). This approach makes it possible to create the most compact and lightweight hub construction. Increasing the number of blades causes certain difficulties with placing joints in the same plane, which causes an increase in the separation of the GS. The main factor determining the minimum permissible spacing of the busbar hubs of the conventional circuit is the provision of a restoring torque Mmn, created by the centrifugal forces of the blade. It is necessary

consider that MW depends on the angle of the blade stroke p.

Usually VSH spacing can be selected from the condition that the range of angles of deflection of the blade in the plane of rotation (autorotation - off) is 12-18 °.

With the correct choice of kinematics in this case, the stability of the blade relative to the VS is ensured. The removal of the shunt at the maximum angles of deflection of the blade in the plane of rotation can not be so reduced and must be proportional to the maximum torque. The transition to modern blades from KM with ul = 6-7 instead of ul = 3,5-5, as on the helicopters of previous generations, requires a certain increase in the removal of the GS required to maintain the range of angles of deviation in the plane of rotation. This, of course, entails a certain increase in the mass of the hub bushing. The change in the frequency of oscillation of the blade in the plane of rotation is achieved by removing the VS, which is due to detuning from the "air" and "terrestrial" resonance. The combination of GS and GS in the form of a cardan unit ensures uniform loading of GSh bearings in all helicopter flight modes (2.4.1, b).

When the mechanical drive of the blades through the hub HB transferred torque M of the engine. Bushing perceives T and Q aerodynamic and inertial forces F and moments arising at the rotor blade, and transmits it to the fuselage (2.4.2).

Mass sleeve bushing is proportional to the centrifugal force of the blade and its length. Therefore, to reduce the weight of the sleeve is advisable to minimize the length of the sleeve. This is prevented by a number of restrictions. The length of the sleeve can not be made smaller than the total size of the maximum move up to the housing units hinges. In addition, reducing sleeves, especially for sleeves multiblade rotor, due to the difficulty of layout character.

The sleeve length is significantly reduced (for a given I piece) on a sleeve with the order of the hinges “GS-OSH-VSh” (Chinook helicopter, 2.4.1, c) and OSH-GSH-VSh (Fletier helicopter, 2.4.1, g ). The structural layout of the sleeve with the combined hinges is shown on the 2.4.3 (helicopter S-58).

The main indicators of design excellence articulated sleeves NV are:

  • - bearing capacity of bearings GSH, VSH and OSH;

  • - the level of stress in the details exposed to variable loads;

  • - resource and the possibility of its further increase;

  • - working capacity of dampers;

  • - weight of the sleeve;

  • - manufacturability of parts and assemblies;

  • - simplicity and ease of maintenance.

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