| The dictionary defines a helicopter as an "aircraft that | | | | civilian helicopter was not given until 1946. |
| flies by means of horizontally rotating blades." It is | | | | Significant developments in helicopter engineering |
| derived from the Greek words helix, meaning spiral, | | | | ensued during the first half of the 20th century, with |
| and pteron, meaning wing. Helicopters may be used | | | | improvements in fuels and engines. The production of |
| for military or civil purposes, including transportation | | | | lightweight turbo shaft engines in the second half of |
| of troops, infantry support, firefighting, business | | | | the 20th century aided in the invention of larger, |
| transportation, medical purposes and police | | | | faster and higher-performance helicopters. The most |
| surveillance. | | | | important apparatus in a helicopter is its rotors, which |
| Aviation pioneers like Jan Bahyl, Louis Breguet, Emile | | | | are commonly designed in the Sikorsky-layout. Many |
| Berliner, and Igor Sikorsky designed the first | | | | helicopters also have a smaller vertical propeller called |
| successful helicopters, with Juan de la Cierva | | | | a tail rotor mounted at the rear of the aircraft. This |
| introducing the first practical autogiro in 1923, which | | | | creates thrust in the opposite direction from the |
| became the platform for the modern helicopter. | | | | torque generated by the main rotor. |
| Raúl Pateras de Pescara, an inventor from | | | | Although helicopters have the advantage of |
| Argentina, demonstrated the first fully controllable | | | | maneuverability and can take off or land vertically |
| helicopter using special controls. The first practical | | | | anywhere, a pilot can still face potential dangers like |
| helicopter, built by German inventor Professor Heinrich | | | | ground resonance, low-G condition, vortex ring state, |
| Focke, could fly at a speed of 75 miles per hour. | | | | etc. Therefore, it is imperative to operate within safe |
| Although mass production of military helicopters | | | | flight patterns and to avoid hazardous conditions. |
| started in 1942, the license for the first certified | | | | |