The idea of vertical flight could be localized in time, in the years of about 400 BC, when was built so called “Chinese top,” consisted of feathers at the end of a stick which was spun between the hands to generate lift. The word “helicopter” comes from two Greek words, “helliko” (spiral) and “pteron” (wing).
#AVERAGE SPEED OF A HELICOPTER FULL#
The helicopter lift force is provided by the main rotor with the blades that spin about the shaft and all the flight maneuvers under the pilot’s full control suppose a significant mechanical and aerodynamic complexity. The continued advance in the computer-aided design, manufacturing, and lightweight materials have permitted new approaches in the helicopter configuration concepts and design. The aerodynamic limitations imposed by the main rotor were understood better and overcome gradually so, the present helicopters are able to fly at about 370 km/h. In the last years, the results obtained in the scientific research of many aeronautical disciplines has allowed for large increase in the flight dynamics, control, navigation, and lift capabilities of helicopters. So far with the help of helicopters, lives of over a million of people were saved. It is able to hover, fly sideward, backward, forward, and perform other desirable maneuvers in civilian field like sea and mountain rescue, police surveillance, and firefighting or in military missions such as battlefield surveillance, troop transport, assault, and antitank operations.
For the short and medium range, the flight efficiency of helicopters is comparable with those of the airplanes. The helicopter belongs to the flight machine category with the highest operational efficiency because it does not need special take-off and landing grounds with expensive utilities and logistics equipment.
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