Backpack helicopter
Encyclopedia
A backpack helicopter is a helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

 motor and rotor
Helicopter rotor
A helicopter main rotor or rotor system is a type of fan that is used to generate both the aerodynamic lift force that supports the weight of the helicopter, and thrust which counteracts aerodynamic drag in forward flight...

 and controls assembly that can be strapped to a person's back, so that he can walk about on the ground wearing it, and can use it to fly. Its harness
Harness
A harness is a looped restraint or support. It can also be referred to as an "hitcharness", especially by the Jordanian Armed Forces. Specifically, it may refer to one of the following harness types:* Bondage harness* Child harness* Climbing harness...

, like a parachute
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...

 harness, should have a strap between the legs, so that the pilot does not fall out of the harness during flight. Some designs may use ducted fan
Ducted fan
A ducted fan is a propulsion arrangement whereby a fan, which is a type of propeller, is mounted within a cylindrical shroud or duct. The duct reduces losses in thrust from the tip vortices of the fan, and varying the cross-section of the duct allows the designer to advantageously affect the...

 design to increase upward thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....

. Several inventors have tried to make backpack helicopters, with mixed results.

Typically a backpack helicopter differs from a conventional helicopter in two ways.
Firstly there is no tail rotor, and the main rotors are contra-rotating
Contra-rotating
Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque. Examples include some aircraft propellers, resulting in the maximum power of a single piston or...

. 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, or turning motion.
Secondly, the rotors are fixed pitch, which assists with simplicity, however this means that in the event of engine failure autorotation
Autorotation
In aviation, autorotation refers to processes in both fixed-wing and rotary-wing aircraft. The term means significantly different things in each context....

 is impossible. Usually a Ballistic parachute
Ballistic parachute
A ballistic parachute, ballistic reserve parachute, or emergency ballistic reserve parachute is a parachute ejected from the casing via a small explosion*, much like that used in an ejection seat. *Also there are slug fired systems, mortar fired systems, , & A.I.R. rocket systems...

 would be incorporated for safety.

A Popular Science magazine in 1969 featured a backpack helicopter that used small jet engines on the tips of the rotors instead of contra-rotating
Contra-rotating
Contra-rotating, also referred to as coaxial contra-rotating, is a technique whereby parts of a mechanism rotate in opposite directions about a common axis, usually to minimise the effect of torque. Examples include some aircraft propellers, resulting in the maximum power of a single piston or...

 rotors. This design could function in autorotation
Autorotation
In aviation, autorotation refers to processes in both fixed-wing and rotary-wing aircraft. The term means significantly different things in each context....

. Related are devices like a backpack helicopter which also include a seat and leg supports and are actually very small open-topped ordinary helicopters. In theory, a helicopter would be more efficient than a rocket/jet pack, possessing a greater specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...

, and being more suited to hovering due to the smaller velocities of the propelled gases.

Examples

Pure backpacks

  • The Heliofly was a make which was designed in Germany
    Germany
    Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

     in 1941 onwards.
  • The Pentecost Hoppicopter was developed by an independent inventor and demonstrated to the military in 1945.
  • Rhyme (made in Japan)
  • Libelula (dragonfly) from Tecnologia Aeroespacial Mexicana (TAM) with a 2-bladed rotor driven by a small rocket motor at the end of each rotor blade. Info. (They also make a jetpack.)
  • The NASA Puffin is another VTOL strap-on helicopter, which like the AeroVironment SkyTote
    AeroVironment SkyTote
    The SkyTote is an unmanned aerial vehicle , tailsitter Vertical Take-Off and Landing -fixed wing hybrid plane, which attains the advantages of both airplane designs...

     can also transition to horizontal flight

With a seat

  • SoloTrek XFV
    SoloTrek XFV
    The SoloTrek XFV was a single-person VTOL aircraft. It was first flown in December 2001 by Millennium Jet Inc, a private company run by Michael Moshier. Millennium Jet subsequently changed its name to Trek Aerospace Inc...

     (Exo-skeletal Flying Vehicle).
  • Martin Jetpack
    Martin Jetpack
    -References:*http://www.businessweek.com/lifestyle/content/jun2010/bw20100615_209271.htm-External links:* * *...

  • 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.
  • GenH4
  • The Aerospace Corporation
    The Aerospace Corporation
    The Aerospace Corporation is a private, non-profit corporation headquartered in El Segundo, California that has operated a Federally Funded Research and Development Center for the United States Air Force since 1960...

    's Springtail

In popular culture

Backpack helicopters are relatively popular gadget
Gadget
A gadget is a small technological object that has a particular function, but is often thought of as a novelty. Gadgets are invariably considered to be more unusually or cleverly designed than normal technological objects at the time of their invention...

 in fiction. The SoloTrek XFV
SoloTrek XFV
The SoloTrek XFV was a single-person VTOL aircraft. It was first flown in December 2001 by Millennium Jet Inc, a private company run by Michael Moshier. Millennium Jet subsequently changed its name to Trek Aerospace Inc...

 has appeared in spy film
Spy film
The spy film genre deals with the subject of fictional espionage, either in a realistic way or as a basis for fantasy . Many novels in the spy fiction genre have been adapted as films, including works by John Buchan, John Le Carré, Ian Fleming and Len Deighton...

s such as the 2003 film Agent Cody Banks
Agent Cody Banks
Agent Cody Banks is an American action comedy film directed by Harald Zwart. Its story follows the adventures of the 15-year-old title character, played by Frankie Muniz, who has to finish his chores, avoid getting grounded, and save the world by going undercover for the CIA as a James Bond type...

.

In real life, backpack helicopters are flown with the pilot's body vertical, but some appear in fiction (for example, in Dan Dare
Dan Dare
Dan Dare is a British science fiction comic hero, created by illustrator Frank Hampson who also wrote the first stories, that is, the Venus and Red Moon stories, and a complete storyline for Operation Saturn...

 comics) which are flown with the pilot's body horizontal.

Several action figures came equipped with backpack helicopters. Such an accessory was released as part of the G.I. Joe
G.I. Joe
G.I. Joe is a line of action figures produced by the toy company Hasbro. The initial product offering represented four of the branches of the U.S. armed forces with the Action Soldier , Action Sailor , Action Pilot , Action Marine and later on, the Action Nurse...

 toyline for any figure to use. The Annihilator
Annihilator
Annihilator may refer to:* Annihilator , a mathematical concept* The annihilator of a vector subspace* Annihilator method, a type of differential operator, used in a particular method for solving differential equations...

 figure had a helicopter back-pack as part of its accessories. Another vertical example is the Turbo-Copter unit for the popular Action Man
Action Man
Action Man is an action figure boys' toy launched in Britain in 1966 by Palitoy as a licensed copy of Hasbro's American "moveable fighting man": G.I...

 toy figure.
  • The 1984 Commodore 64
    Commodore 64
    The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...

     game H.E.R.O.
    H.E.R.O.
    H.E.R.O. is a single-player video game published by Activision. First developed for the Atari 2600 and released in March 1984, the game was ported to many of the home computers and gaming consoles of that era...

     (Helicopter Emergency Rescue Operation) featured a protagonist who wore a helicopter backpack
  • The game Super Monkey Ball Deluxe
    Super Monkey Ball Deluxe
    Super Monkey Ball Deluxe is a party video game made for the PlayStation 2 and the original Xbox developed by Japanese game developer Sega, the creators of Sonic the Hedgehog, and is the fourth entry in the Super Monkey Ball series of games. It is the first game in the main Super Monkey Ball series...

     shows Dr. Bad-Boon using a backpack helicopter
  • In the 2009 game Scribblenauts
    Scribblenauts
    Scribblenauts is an emergent puzzle action video game developed by 5th Cell for the Nintendo DS published by WB Games. The game was released September 15, 2009 in North America, September 30, 2009 in Australia, and October 9, 2009 in Europe. Konami released the game in Japan under the name on...

     a backpack helicopter can be summoned using the phrase "helibackpack".
  • In the 1973 Woody Allen film "Sleeper" Allen's character Miles Monroe tries to escape from the government's security police while using a largely ineffective backpack helicopter. He could not rise more than a few feet off the ground and only for several seconds, despite much arm-flapping.
  • Rotor, a villain from the 2010 LEGO Hero Factory
    Hero Factory
    Hero Factory is a line of toys by the LEGO Group marketed primarily at 6 to 16-year-olds. It was created in response to the decision to discontinue the Bionicle theme in early 2010.-Production:...

     toyline, has a helicopter pack that he uses as a weapon and a flight mechanism.
  • A backpack helicopter is featured in the Ratchet and Clank series.
  • Karlsson-on-the-Roof
    Karlsson-on-the-Roof
    Karlsson-on-the-Roof is a fictional character in a series of children's books created by Swedish author Astrid Lindgren. The cartoon adaptation became popularised in the USSR with its release in the 1970s...

     from books of Astrid Lindgren
    Astrid Lindgren
    Astrid Anna Emilia Lindgren , 14 November 1907 – 28 January 2002) was a Swedish author and screenwriter who is the world's 25th most translated author and has sold roughly 145 million copies worldwide...

    has something similar to a backpack helicopter on his back.
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