The principle of helicopter flight is similar to the bamboo dragonfly.
The helicopter was modeled after the Chinese bamboo dragonfly. The bamboo dragonfly, also known as the flying spiral and the "Chinese gyro", is a curious invention of our ancestors. Modern helicopters, though millions of times more complex, have similar principles of flight to the bamboo dragonfly.
The rotor blades of a modern helicopter are like the blades of a bamboo dragonfly, the rotor shaft is like the thin bamboo stick of a bamboo dragonfly, and the engine that drives the rotor blades is like our hands rubbing the bamboo stick.
The maximum speed of the helicopter can reach more than 300km/h, the dive limit speed of nearly 400km/h, the practical limit of lift up to 6000 meters (world record 12450m), the general range up to 600 ~ 800km or so. The general range can be 600-800km. The range of the aircraft can be more than 2000km by carrying the in-flight and out-flight fuel tanks.
Advantages of helicopters
The helicopter's outstanding feature is that it can do maneuvering flights at low altitude (a few meters above the ground), low speed (from hovering), and unchanged nose direction, and especially can take off and land vertically in a small area. 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.
Reference: Baidu Encyclopedia-Helicopters