A captive helicopter is a

helicopter A helicopter is a type of rotorcraft in which Lift (force), lift and thrust are supplied by horizontally spinning Helicopter rotor, rotors. This allows the helicopter to VTOL, take off and land vertically, to hover (helicopter), hover, and ...

which is tethered to the ground with a rope, as with a captive balloon. Captive helicopters can be used for the same purposes as captive balloons. A primary advantage of captive helicopters is that they can be more accurately steered than captive balloons or

kite A kite is a tethered heavier than air flight, heavier-than-air craft with wing surfaces that react against the air to create Lift (force), lift and Drag (physics), drag forces. A kite consists of wings, tethers and anchors. Kites often have ...

s in order to compensate for the influence of the wind. A further advantage is that, unlike kites, they can be launched in the absence of wind. Their main disadvantages are that they require power for their flight and are very noisy. Unlike kites (which rely solely on the wind for power) and balloons (which require specialty lighter-than-air gases), helicopters are normally powered by

aviation fuel Aviation fuels are either petroleum-based or blends of petroleum and synthetic fuels, used to power aircraft. They have more stringent requirements than fuels used for ground applications, such as heating and road transport, and they contain add ...

s. However, it is possible to run captive helicopters electrically by running a cable inside the tether line holding the helicopter. In 1887, Parisian electrical engineer Gustave Trouvé demonstrated his tethered electric model helicopter at a meeting of the French Association for the Advancement of Sciences in Toulouse. At the end of the 1930s, the German company

Telefunken Telefunken was a German radio and television producer, founded in Berlin in 1903 as a joint venture between Siemens & Halske and the ''AEG (German company), Allgemeine Elektrizitäts-Gesellschaft'' (AEG) ("General electricity company"). Prior to ...

tried to make a longwave transmission experiment with a captive helicopter driven with a three-phase, AC-power engine. The helicopter should have reached a height of 1000 metres. Because of electrostatic charges induced by earth's

electric field An electric field (sometimes called E-field) is a field (physics), physical field that surrounds electrically charged particles such as electrons. In classical electromagnetism, the electric field of a single charge (or group of charges) descri ...

, the fuses melted when the captive helicopter reached a height of 750 metres and the captive helicopter landed roughly.Klawitter, Gerd; Herold Klaus; Oexner, Michael (2000). ''Langwellen- und Längstwellenfunk''. Germany: Siebel Verlag. {{ISBN, 3-922221-48-3.

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Electric Tethered Observation Platform (modern captive electric helicopter)

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See also