This article is about jet or rocket-powered flying devices. For other uses, see Jetpack (disambiguation).
- The Martin Jetpack is a small semi-backpack helicopter, not a jetpack, despite its name.
Jet pack, rocket belt, rocket pack and similar names are used for various types of devices, usually worn on the back, that are propelled by jetsof escaping gases (or in some cases liquid water) so as to allow a single user to fly.
The concept emerged from science fiction in the 1920s and became popular in the 1960s as the technology became a reality. The most common use of the jet pack has been in extra-vehicular activities for astronauts. Despite decades of advancement in the technology, the challenges ofEarth's atmosphere, Earth's gravity, and the fact that the human body is not adapted to fly naturally remain an obstacle to its potential use in the military or as a means of personal transport.
Andreyev[edit]
History[edit]
The first jet pack was developed in 1919 by the Russian inventor Aleksandr Fyodorovich Andreyev. The project was thought-of highly by Nikolai Rynin and technology historians Yu. V. Biryukov and S. V. Golotyuk.[1] Later it was issued a patent but apparently was not built or tested.[2]
German Himmelstürmer of World War II[edit]
Christof Friedrich, a pseudonym for Holocaust denier Ernst Zündel, published a book in 1976 claiming that, in World War II, Germany conducted late-war experiments by strapping two wearable shortened Schmidt pulse jet tubes of low thrust to the body of a pilot.[3] However, outside of the unreliable claims of Zündel, no other evidence exists that these experiments. or that the so-calledHimmelstürmer ("sky stormer") program, actually existed. What evidence that Zündel supplied was a hoax.[4]
Various development approaches
AeropackIn 1958, Garry Burdett and Alexander Bohr, Thiokol Corporation engineers, created a Jump Belt which they named Project Grasshopper. Thrust was created by high-pressure compressednitrogen. Two small nozzles were affixed to the belt and directed vertically downward. The wearer of the belt could open a valve, letting out nitrogen from the gas cylinder through the nozzles, which tossed him upward to a height of 7 meters. After leaning forward, it was possible with the aid of the jump belt's thrust to run at 45 to 50 km/h. Later, Burdett and Bohr tested a hydrogen peroxide-powered version. The jump belt was demonstrated by a serviceman in action[citation needed], but as no financing was forthcoming, there was no further testing.
In 1959 Aerojet General Corporation won a U.S. Army contract to devise a jet pack or rocket pack. At the start of 1960 Richard Peoples made his first tethered flight with his Aeropack.
In 1960, the Bell Rocketbelt was presented to the public. The jet of gas was provided by a hydrogen peroxide-powered rocket, but the jet could also be provided by a turbojet engine, a ducted fan, or other kinds of rockets powered by solid fuel, liquid fuel or compressed gas (usually nitrogen).
U.S. Army interest[edit]
American servicemen did not lose interest in this type of flight vehicle. Transport studies of the U.S. Army Transportation Research Command (TRECOM) determined that personal jet devices could have diverse uses: for reconnaissance, crossing rivers, amphibious landing, accessing steep mountain slopes, overcoming minefields, tactical maneuvering, etc. The concept was named "Small Rocket Lift Device", SRLD.
Within the framework of this concept the administration concluded a big contract with the Aerojet General company in 1959 to research the possibility of designing an SRLD suitable for army purposes. Aerojet came to the conclusion that the version with the engine running on hydrogen peroxide was most suitable. However, it soon became known to the military that engineer Wendell Moore of the Bell Aerosystems company had for several years been carrying out experiments to make a personal jet device. After becoming acquainted with his work, servicemen during August 1960 decided to commission Bell Aerosystems with developing an SLRD. Wendell Moore was appointed chief project engineer.
Hydrogen peroxide-powered rocket packs[edit]
A hydrogen peroxide-powered motor is based on the decomposition reaction of hydrogen peroxide. Nearly pure (90% in the Bell Rocket Belt) hydrogen peroxide is used. Pure hydrogen peroxide is relatively stable, but in contact with a catalyst (for example, silver) it decomposes into a mixture of superheated steam and oxygen in less than 1/10 millisecond, increasing in volume 5000 times: 2 H2O2 → 2 H2O + O2. The reaction is exothermic, i.e., accompanied by the liberation of much heat (about 2500 kJ/kg), forming in this case a steam-gas mixture at 740 °C. This hot gas is used exclusively as the reaction mass and is fed directly to one or more jet nozzles.
The great disadvantage is the limited operating time. The jet of steam and oxygen can provide significant thrust from fairly lightweight rockets, but the jet has a relatively low exhaust velocity and hence a poor specific impulse. Currently, such rocket belts can only fly for about 30 seconds (because of the limited amount of fuel the user can carry unassisted).
A more conventional bipropellant could more than double the specific impulse. However, although the exhaust gases from the peroxide-based motor are very hot, they are still significantly cooler than those generated by alternative propellants. Using a peroxide-based propellant greatly reduces the risk of a fire/explosion which would cause severe injury to the operator.
In contrast to, for example, turbojet engines which mainly expel atmospheric air to produce thrust, rocket packs are far simpler to build than devices using turbojets. The classical rocket pack construction of Wendell Moore can be made under workshop conditions, given good engineering training and a high level of tool-making craftsmanship.
The main disadvantages of this type of rocket pack are:
- Short duration of flight (a maximum of around 30 seconds).
- The high expense of the peroxide propellant.
- The inherent dangers of flying below minimum parachute altitude, and hence without any safety equipment to protect the operator if there is an accident or malfunction.
- Safely learning how to fly it, given that there are no dual-control training versions.
- The sheer difficulty of manually flying such a device.
These circumstances limit the sphere of the application of rocket packs to very spectacular public demonstration flights, i.e., stunts, but due to their strong visual impact, rocket pack flights are guaranteed to seize the attention of spectators.[citation needed] As a result, rocket pack flights enjoy great success at major sporting events. For example, a flight was arranged in the course of the opening ceremony of the summer Olympic Games 1984 in Los Angeles, USA.
Bell Textron Rocket Belt[edit]
Main article: Bell Rocket Belt
This is the oldest known type of jet pack or rocket pack. One Bell Rocket Belt is on display at the Smithsonian Institution's National Air and Space Museumannex, the Steven F. Udvar-Hazy Center, located near Dulles Airport.
RB-2000 Rocket Belt[edit]
This was a successor to the Bell Rocket Belt.[5] See Bell Rocket Belt#RB2000 Rocket Belt.
Bell Pogo[edit]
Main article: Bell Pogo
The Bell Pogo was a small rocket-powered platform that two people could ride on. Its design used features from the Bell Rocket Belt.
Powerhouse Productions Rocketbelt[edit]
More commonly known as "The Rocketman", Powerhouse Productions, owned and operated by Kinnie Gibson, is the first company to manufacture the 30 second flying Rocketbelt (June 1994) and to exclusively organize Rocketbelt performances. Since 1983 Powerhouse Productions has performed show flights in over 40 countries such as the Carnival in Rio de Janerio, Super Bowls, the Rose Parade, Daytona 500, and the Michael jackson Dangerous World Tour, as well as many television shows including Walker Texas Ranger, The Fall Guy and NCIS. Powerhouse Rocketbelt pilots include stuntman Kinnie Gibson and Dan Schlund.[6]
Tecnologia Aeroespacial Mexicana[edit]
The Tecaeromex Rocket Belt is made by the OathKeeper Inc. Company, run by its vice president, Clayton Bruce Reed Tecnologia Aeroespacial Mexicana.[7] This is said to be the only company in the world offering a flying and tested rocket belt package. It was featured in the March 2006 issue of Popular Science magazine and many TV programs around the world like the Discovery Channel, the BBC, ProSieben, TV Azteca, The Science Channel, and The History Channel. Its maker claims that four of his rocketpacks are flying now; his first tethered flights were on 22 September 2005.
On August 11, 2006, the inventor's daughter, Isabel Lozano, was the first woman in the world to fly tethered in a rocket belt in front of millions of TV spectators; she flew with a special rocket belt built by Tecnologia Aeroespacial Mexicana (TAM).[8][9] It runs on hydrogen peroxide and sells for USA $125,000 including a training course.
TAM has also developed a concept for a backpack helicopter called Libellula, with a two-bladed rotor driven by a small rocket motor at the end of each rotor blade.[10]
Jetpack International[edit]
Jetpack International[11] made three types of wingless jet packs:
| Name | Max flight time | Max distance | Max speed | Max height | Max pilot weight | Fuel | Motor type | Fuel capacity | Price |
|---|---|---|---|---|---|---|---|---|---|
| Jet pack H202 | 23 seconds | 152 m | 112 km/h | 37 m | 81 kg | H2O2 | rocket | 22 litre | Not for sale |
| Jet pack H202-Z | 33 seconds | 457 m | 124 km/h | 76 m | 81 kg | H2O2 | rocket | 30 litre | Not for sale |
| Jet pack T-73 | ~9 minutes | c. 18 km | ~134 km/h | ~76 m | 81 kg | Jet-A fuel | T-73 jet motor | 19 litre | $200,000 |
A Jet Pack H202 was flown for 34 seconds in Central Park on the 9 April 2007 episode of the Today Show and sold for $150,000. As of January 2009 their H202 jet packs are for demonstration only, not for sale.[12] Details of the likely consumer model "Falcon" were scheduled for an official announcement on May 1, 2012, but the company is currently behind schedule.[13]
Externally-Powered High Density Propellant[edit]
The thrust for jet packs depends on the density of the propellant and the flow rate. Many self-contained jetpacks have weight restrictions which prevent the use of higher density propellants. JetLev markets a jetpack which uses water as a propellant and obtains a high pressure water stream from a floating "follower". Top speed is 25 mph, maximum height is 30 ft, range is 80 miles, and duration is 4 hours. The cost is $99,500USD.[14]
Turbojet pack[edit]
Packs with a turbojet engine are fueled with traditional kerosene-based jet fuel. They have higher efficiency, greater height and a duration of flight of many minutes, but they are complex in construction and very expensive. Only one working model of this pack was made; it underwent flight tests in the 1960s and at present it no longer flies.
Bell Jet Flying Belt[edit]
In 1965 Bell Aerosystems concluded a new contract with the Defense Advanced Research Projects Agency (DARPA) to develop a jet pack with a turbojet engine. This project was called the "Jet Flying Belt", or simply the "Jet Belt". Wendell Moore and John K. Hulbert, a specialist in gas turbines, worked to design a new turbojet pack. Williams Research Corporation (now Williams International) in Walled Lake, Michigan, designed and built a new turbojet engine to Bell's specifications in 1969. It was called the WR19, had a rated thrust of 430 pounds of thrust (195 kgf, 1,910newtons) and weighed 68 pounds (31 kg).
The first free flight of the Jet Belt took place on 7 April 1969 at the Niagara Falls Municipal Airport. Pilot Robert Courter flew about 100 meters in a circle at an altitude of 7 meters, reaching a speed of 45 km/h. The following flights were longer, up to 5 minutes. Theoretically, this new pack could fly for 25 minutes at velocities up to 135 km/h.
In spite of successful tests, the U.S. Army lost interest. The pack was complex to maintain and too heavy. Landing with its weight on his back was hazardous to the pilot, and catastrophic loss of a turbine blade could have been lethal.
Thus, the Bell Jet Flying Belt remained an experimental model. On 29 May 1969, Wendell Moore died of complications from a heart attack he had suffered six months earlier, and work on the turbojet pack was ended. Bell sold the sole version of the "Bell pack", together with the patents and technical documentation, to Williams Research Corporation. This pack is now in the Williams International company museum.
Special features of the turbojet pack[edit]
The "Jet Belt" used a small turbofan engine which was mounted vertically, with its air intake downward. Intake air was divided into two flows. One flow went into the combustion chamber, the other flow bypassed the engine, then mixed with the hot turbine gases, cooling them and protecting the pilot from the high temperatures generated. In the upper part of the engine the exhaust was divided and entered two pipes which led to jet nozzles. The construction of the nozzles made it possible to move the jet to any side. Kerosene fuel was stored in tanks beside the engine. Control of the turbojet pack was similar to the rocket pack, but the pilot could not tilt the entire engine. Maneuvering was by deflecting the nozzles. By inclining levers, the pilot could move the jets of both nozzles forward, back, or sideways. The pilot rotated left/right by turning the left handle. The right handle governed the engine thrust. The jet engine was started with the aid of a powder cartridge. While testing this starter, a mobile starter on a special cart was used. There were instruments to control the power of the engine, and a portable radio to connect and transmit telemetry data to ground-based engineers. On top of the pack was a standard auxiliary landing parachute; it was effective only when opened at altitudes above 20 meters. This engine was later the basis for the propulsion units of Tomahawk and other cruise missiles.
Space[edit]
Rocket packs can be useful for extra-vehicular activity (EVA) in outer space. While near Earth a jet pack has to produce a g-force of at least 1g (otherwise it just provides some steering capacity for the wearer while falling down to Earth). For excursions outside a free falling spaceship, even a small g-force is already sufficient for a small deviation from free fall, hence much less delta-v is consumed per unit time, and not during the whole EVA. With only small amounts of thrust needed, safety and temperature are much more manageable than in the atmosphere in Earth's gravity field.
NASA's Manned Maneuvering Unit (MMU)[edit]
In the 1980s, NASA demonstrated the Manned Maneuvering Unit (MMU), a rocket pack that allowed an astronaut to function as his/her own spacecraft, but the system was retired before the decade was over. The MMU is the only jet pack of practical importance. Its operational area is outside a space station orspacecraft, where an astronaut can limitedly move independently. The MMU's propulsion was produced by high-pressure nitrogen gas discharged through nozzles (of which the MMU has 24). The MMU was used after 1984 in three Space Shuttle missions (STS-41-B, STS-41-C and STS-51-A).
NASA's SAFER[edit]
During mission STS-64, NASA Mission Specialists Carl Meade and Mark Lee tested the SAFER, a smaller, simpler version of the MMU now carried by astronauts while performing EVA in case of an astronaut's accidental separation from spacecraft or space station.
Winged jet and rocket packs[edit]
Visa Parviainen's jet-assisted wingsuit[edit]
On 25 October 2005 in Lahti in Finland, Visa Parviainen jumped from a hot air balloon in a wingsuit with two small turbojet jet engines attached to his feet. Each turbojet provided approximately 16 kgf (160 N, 35 lbf) of thrust and ran on kerosene (Jet A-1) fuel. Parviainen apparently achieved approximately 30 seconds of horizontal flight with no noticeable loss of altitude.[15]
Yves Rossy's jet wingpack[edit]
Swiss ex-military and commercial pilot Yves Rossy developed and built a winged pack with rigid aeroplane-type carbon-fiber wings spanning about 8 feet (2.4 m) and four small kerosene-burning jet engines underneath; these engines are large versions of a type designed for model aeroplanes.[16] He wears a heat-resistant suit similar to that of a firefighter or racing driver to protect him from the hot jet exhaust.[17][18] Similarly, to further protect the wearer, the engines are modified with the addition of a carbon fibre heat shield extending the jet nozzle around the exhaust tail.
Rossy claims to be "the first person to gain altitude and maintain a stable horizontal flight thanks to aerodynamic carbon foldable wings", which are folded by hinges at their midpoint. After being lifted to altitude by a plane, he ignites the engines just before he exits the plane with the wings folded. The wings unfold while in free-fall, and he is then able to fly horizontally for several minutes, landing with the help of a parachute.[19] He achieves true controlled flight using his body and a hand throttle to maneuver.
The system is said by Rossy to be highly responsive and reactive in flight, to the point where he needs to closely control his head, arm and leg movements in order not to enter an uncontrolled spin. The engines on the wing require precise common alignment during set-up, also in order to prevent instability. An electronic starter system ensures that all four engines ignite simultaneously. In the event of a spin, the wing unit can be detached from the pilot, and both pilot and wing unit descend to Earth on separated parachutes.
Rossy's jet pack was exhibited on 18 April 2008 on the opening day of the 35th Exhibition of Inventions at Geneva.[20] Rossy and his sponsors spent over $190,000 to build the device.[21] His first successful trial flight was on 24 June 2004 near Geneva, Switzerland. Rossy has made more than 30 powered flights since. In November 2006 he flew with a later version of his jet pack.[citation needed] On 14 May 2008 he made a successful 6-minute flight from the town of Bex near Lake Geneva. He exited a Pilatus Porter at 7,500 feet (2,300 m) with his jet pack. It was the first public demonstration before the world's press. He made effortless loops from one side of the Rhone valley to the other and rose 2,600 feet (790 m).
It has been claimed that the military was impressed and asked for prototypes for the powered wings, but that Rossy kindly refused the request stating that the device was only intended for aviation enthusiasts.[22][23][24]
On 26 September 2008, Yves successfully flew across the English Channel from Calais, France to Dover, England in 9 minutes, 7 seconds.[25][26] His speed reached 186 mph (299 km/h) during the crossing,[27] and was 125 mph (201 km/h) when he deployed the parachute.[28] Since then he has—in several flights—managed to fly in a formation with three military jets and cross the Grand Canyon, but he failed to fly across the Strait of Gibraltar—he made an emergency landing in the water.
Current technology[edit]
According to the U.S. Government, real jetpacks have little practical value due to the limitations of current technology.[citation needed] The United States Armed Forces, which conducted most jet pack research, has declared that helicopters are far more practical.[citation needed] Many others have worked on devising a functional jet pack, but with limited success.
In recent years, the rocket pack has become popular among enthusiasts, and some have built them for themselves. The pack's basic construction is rather simple, but its flying capability depends on two key parts: the gas generator, and the thrust control valve. The rocket packs being built today are largely based on the research and inventions of Wendell Moore at Bell Helicopter.
One of the largest stumbling blocks that would-be rocket pack builders have faced is the difficulty of obtaining concentrated hydrogen peroxide, which is no longer produced by many chemical companies. The few companies that produce high-concentration hydrogen peroxide only sell to large corporations or governments, forcing some amateurs and professionals to set up their own hydrogen peroxide distillation installations. High-concentration hydrogen peroxide for rocket belts was produced by Peroxide Propulsion (Gothenburg, Sweden) from 2004 to 2010,[29] but after a serious accident Peroxide Propulsion stopped making it.[30]
Two high-profile jet pack projects are currently being operated:
Home-made versions[edit]
Episode 32 of MythBusters investigates the urban legend of an affordable jet pack or rocket pack that can be built from plans purchased on the Internet. Extensive modifications were made by the MythBusters team due to vagueness in the plans and because of the infeasibility of the specified engine mounting system. The jet pack produced by the MythBusters had two ducted fanspowered by ultralight-type piston engines. (Fans[who?] complained that the use of piston engines destroyed the whole idea of the pack's being truly based on jets, by which, presumably, they meant self-contained gas turbines.) They found it was not powerful enough to lift a person off the ground, and was expensive to build. The plans specified a Rotax 503 ultralight engine, but they intended to use the more powerful and lighter Rotax 583 engine before a similar lighter unnamed engine was substituted.[31]
America's only "private rocketeer", Gerard Martowlis, built a fully operational rocket pack. Like all flying packs, his is extraordinarily difficult and extremely dangerous to fly, taking many hours to learn and practice. He performed his test flights using a safety tether system in case he lost control. A consequence of the short flight time of any peroxide-based pack is that the entire flight is below the minimum parachute altitude. Accordingly, any loss of control or failure of the pack is most likely fatal. The training also incurs expensive fuel costs.[quantify]
References in popular culture[edit]
The concept of jet packs appeared in popular culture, particularly science fiction long before the technology became practical. Perhaps the first appearance was in pulp magazines. The 1928 cover of Amazing Stories featured a man flying with a jet pack.
When Republic Pictures planned to do a superhero serial using its renown "flying man" scenes as used in The Adventures of Captain Marvel, the character of Captain Marvel was tied up in litigation with the owners of the character of Superman. For its postwar superhero serial, Republic used a jet pack in King of the Rocket Men. The same stock special effects were used in other serials.
While several science fiction novels from the 1950s featured jet packs, it was not until the "Bell Rocket Belt" in the 1960s that the jet pack caught the imagination of the mainstream. Bell's demonstration flights in the U.S. and other countries created significant public enthusiasm.
Two episodes of the 1964 animated series Jonny Quest featured characters using jet packs (referred to as "rocket belts").
In 1965 the jet pack appeared in the James Bond movie Thunderball when 007 played by Sean Connery used a jet pack in the pre-title sequence to escape the bad guys and rendezvous with his French contact. The pack was piloted by Gordon Yaeger and Bill Suitor. The jet pack had a brief cameo in Die Another Day. In the same year of 1965 it appeared in the pilot episode[citation needed] of Lost in Space with jet pack stock footage appearing in the television series several times. The jet pack from Thunderball was also featured, though somewhat anachronistically, in the 2005 video game adaptation of From Russia With Love
A Bell Rocket Belt was featured extensively in the 1976 CBS Saturday morning children's live action TV show Ark II.
A rocket pack (unknown make) was seen in an episode of the TV series The Fall Guy.
A jet pack was also the basis of an episode of Gilligan's Island.
A rocket pack flight famously occurred on the opening of the summer Olympic Games in Los Angeles in 1984, piloted by Bill Suitor, who landed opposite the presidential platform, where Ronald Reagan sat.
A rocket pack was used to deliver the game ball at the 2011 University of Michigan vs. Purdue University football game in Ann Arbor, Michigan. The pack was piloted by Eric Scott and powered by hydrogen peroxide.[32]
In the 1991 period action/adventure film The Rocketeer, the protagonist, Cliff Secord (played by Billy Campbell), acquires a stolen military jet pack, and uses it to become the eponymous superhero.
Jet-packs appear in the popular video game Halo: Reach. On September 13, 2010, during a Halo: Reach launch party at London, England's Trafalgar Square, stuntman Dan Schlund of Powerhouse Productions Inc "Rocketman" firm (which provides jet packs for use by marketing and sporting companies) donned a Halo-esque "Spartan armor" suit and a jet pack and maintained flight for 30 seconds before landing safely.[33] The jet-pack also appears in the 2012 video game Halo 4, developed by 343 Industries.
Jetpacks also appeared in other video games, including BloodRayne (worn by Nazi troopers), Tribes, Giants: Citizen Kabuto, Armed and Dangerous, and the Pilotwings series, in which it is referred to as a "Rocket Belt". It is also found in famous gta video game series that is in Grand Theft Auto: San Andreas.
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