Rotor shaft
Helicopter rotor shaft

Helicopter rotor shaft


NV shaft is loaded by forces and moments on his sleeve and the torque generated at the output of GH. HB Nala length is determined by field layout, aerodynamic and operational considerations.

From the layout considerations of choosing the minimum allowable height HB accommodation sleeve above the fuselage, taking into account the deflection of the blade; aerodynamic - determine the excess back HB above the front of the helicopter in longitudinal scheme; Maintenance - define the safe height HB plane in finding staff in the area of ​​the rotating screw.

The distance between the co-axial screws is chosen from the condition of ensuring an adequate supply on the approximation, which prevents collision of the upper and lower screws of the blades in all flight modes, and if the necessary evolutions.

Forces and moments caused in the rotating shaft of variable bending stress, changing with the speed of the screw. The values ​​of forces and moments are determined from the aerodynamic calculation of the helicopter. Their value significantly affects the alignment of the helicopter, which changes when you change the direction of thrust of the screw shaft relative to HB. This changes the magnitude and the resultant transverse force acting on the shaft.

In order to increase the flexural endurance of the shafts, in addition to choosing a rational configuration (smooth transitions from one diameter to another, large radiuses of rounding), appropriate technological processing techniques are applied, in particular, with hardening of the shot. Hardened can be exposed as a shaft entirely, from the outside and from the inside (with the exception of, for example, carvings), and individual places, the most dangerous in terms of endurance. Threads in dangerous sections can be hardened by knurling. The roughness of processing the surfaces of the shafts in the zone of significant bending stresses is not more than R z = 2,5. In some cases, subsequent polishing of surfaces is introduced.

4.3.4, a shows the KSS of the rear shaft of the NV of the helicopter of the longitudinal scheme CH-47. The shaft of an experimental Boeing-360 helicopter is made of composite material.

The KCC shaft helicopter HB ONE-84 effected separation of the console tree pas two autonomous element. The inner shaft (spring) 5 is designed to transmit torque from the gearbox to the hub HB. Thrust and shear forces are perceived HB stationary relative to the fuselage outer cantilever shaft 4.

To ensure the operability of the shaft must be met, primarily, the conditions of their strength and rigidity. Only if the shaft transmits torque Mcr, its diameter can be found by the formula.


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