The outstanding feature of helicopter is that it can do maneuvering flight with low altitude (several meters from the ground), low speed (from hovering) and constant nose direction, especially it 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 has been widely used in ground attack, landing, weapons delivery, logistical support, battlefield rescue, reconnaissance and patrol, command and control, communications, anti-submarine mine clearance, electronic countermeasures. In the civilian aspects of the application of short-distance transportation, medical care, disaster relief, emergency rescue, lifting equipment, geological exploration, forest protection and fire fighting, aerial photography, etc..
Helicopter speed:
The maximum speed of the helicopter can be up to 300km/h or more, the dive limit speed of nearly 400km/h, the practical limit of lift of up to 6,000 meters (the world record is 12,450m), the general range of up to 600-800km or so. The general range can reach 600-800km. The range of carrying in-flight and external fuel tanks can reach more than 2000km. According to the different needs of the helicopter has a different takeoff weight.
Currently the world's largest heavy helicopter in use is the Russian Mi-26 (maximum takeoff weight of 56t, payload 20t). The current practical application is a mechanically driven single-rotor helicopter and dual-rotor helicopter, of which the single-rotor helicopter is the largest number.