1, single-rotor type
Helicopter engine drive rotor to provide lift, the helicopter lifted in the air, single-rotor helicopter's main engine at the same time also output power to the tail of the small propeller, the on-board gyroscope can detect helicopter slewing angle and feed back to the tail rotor, through the adjustment of the pitch of the small propeller can be counteracted by the large propeller produced by the different speed of the reaction force. Twin-rotor helicopters usually use relative rotation of the rotors to counteract the unbalanced lift generated by the rotors.
2, dual-rotor type
Through the mechanism called "tilt disk" can change the helicopter rotor blade angle, so as to realize the rotor cycle pitch, so as to change the rotor rotating plane of the different positions of the lift to achieve the change of the helicopter's flight attitude, and then the direction of the direction of change in the direction of flight with the change of the direction of the lift.
At the same time, the engine of the helicopter is kept at a relatively stable rotational speed after the helicopter lifts off, and the helicopter's ascent and descent are controlled by adjusting the rotor's total pitch to get different total lift, so the helicopter realizes vertical takeoff and landing.
Features:
The outstanding features of the helicopter are that it can do maneuvering flight at low altitude (several meters above the ground), low speed (from hover) and constant nose direction, especially it can take off and land vertically in a small field. Because of these characteristics make it has a wide range of uses and development prospects.
In the military aspect, it has been widely used in ground attack, airborne landing, weapon transportation, logistic support, battlefield rescue, reconnaissance patrol, command and control, communication and liaison, anti-submarine and mine clearance, and electronic countermeasures.
In civil applications, it is used in short-distance transportation, medical care, disaster relief, emergency rescue, lifting equipment, geological exploration, forest protection and firefighting, and aerial photography. The transportation of personnel and materials between oil wells and bases at sea is an important aspect of civil use.