A backpack helicopter / helipack 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 ...

motor and

rotor ROTOR was an elaborate air defence radar system built by the British Government in the early 1950s to counter possible attack by Soviet bombers. To get it operational as quickly as possible, it was initially made up primarily of WWII-era syst ...

and controls assembly that can be strapped to a person's back, so they can walk about on the ground wearing it, and can use it to fly. It uses a harness like a

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

harness and should have a strap between the legs (so the pilot does not fall out of the harness during flight). Some designs may use a

ducted fan In aeronautics, a ducted fan is a thrust-generating mechanical fan or Propeller (aeronautics), propeller mounted within a cylindrical wiktionary:duct, duct or shroud. Other terms include ducted propeller or shrouded propeller. When used in vertic ...

design to increase upward

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

. Several inventors have tried to make backpack helicopters, with mixed results. Typically, a backpack helicopter differs from a conventional helicopter in two main ways: First, there is no tail rotor, and the main rotors are contra-rotating. Yaw is controlled by fine adjustment of a differential gear in the rotor drive transmission. When one rotor is adjusted to spin slightly faster than the other, it induces yaw (turning motion). Second, the rotors are fixed pitch, which assists with simplicity; this means, however, that in the event of engine failure autorotation is impossible. Usually, a ballistic parachute would be incorporated for safety. An edition of ''

Popular Science Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience. While science journalism focuses on recent scientific developments, popular science is more broad ranging. It may be written ...

'' magazine in 1969 featured a backpack helicopter that used small jet engines in a tip jet configuration instead of contra-rotating rotors. This design could function in autorotation. Related are devices like a backpack helicopter which also include a seat and leg supports, which are small, open-topped helicopters. In theory, a helicopter would be more efficient than a rocket-powered jetpack, possessing a greater

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

, and being more suited to hovering, due to the lower velocities of the propelled gases. Australian electric company CopterPack had developed "an electric backpack helicopter with a self-levelling autopilot", and released test videos in June 2021. However, the device consists of two rotors with diameters around connected via

carbon fiber Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers ( Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon comp ...

tubes to a backpack with battery packs, and a pair of armrests with hand controls on them. Later video analysis revealed operator and equipment were at the end of a drop cable that was edited out using post-production software.

Examples

Pure backpacks

* The Heliofly was a make which was designed in

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

in 1941 onwards. * The Pentecost HX-1 Hoppi-Copter was developed by Horace T. Pentecost, an independent inventor and demonstrated to the military in 1945. * Rhyme (made in Japan) * The Libelula ("dragonfly") from Tecnologia Aeroespacial Mexicana has a 2-bladed rotor driven by a small rocket motor at the end of each rotor blade. The company also manufactures a jetpack.

With a seat

* SoloTrek XFV (Exo-skeletal Flying Vehicle). * Martin Jetpack * Vortech designed various models which have seats. They formerly also made a pure backpack model with two very long rotor blades driven by a little propane-powered jet motor at the end of each blade. *

GEN H-4 The GEN H-4 is a Japanese ultralight coaxial helicopter under development by GEN Corporation of Nagano. The aircraft is intended to be supplied as a kit for amateur construction.Bayerl, Robby; Martin Berkemeier; et al: ''World Directory of Le ...

* Hirobo * Trek Aerospace's Springtail

References

{{Emerging technologies, transport=yes Aircraft configurations Helicopters Ultralight aircraft

Examples

Pure backpacks

With a seat

See also

References