Jet pack
Encyclopedia
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
of escaping gases (or in some cases liquid water) so as to allow a single user to fly
Flight
Flight is the process by which an object moves either through an atmosphere or beyond it by generating lift or propulsive thrust, or aerostatically using buoyancy, or by simple ballistic movement....
.
The concept of these devices emerged from science fiction
Science fiction
Science fiction is a genre of fiction dealing with imaginary but more or less plausible content such as future settings, futuristic science and technology, space travel, aliens, and paranormal abilities...
in the 1920s and became popular in the 1960s as the technology became a reality. Currently, the only practical use of the jet pack has been extra-vehicular activity
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
for astronauts. Despite decades of advancement in the technology, the challenges of Earth's atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
, Earth's gravity
Earth's gravity
The gravity of Earth, denoted g, refers to the acceleration that the Earth imparts to objects on or near its surface. In SI units this acceleration is measured in metres per second per second or equivalently in newtons per kilogram...
, and the human body
Human body
The human body is the entire structure of a human organism, and consists of a head, neck, torso, two arms and two legs.By the time the human reaches adulthood, the body consists of close to 100 trillion cells, the basic unit of life...
(which is not well suited for this type of flight) remain an obstacle to its potential use in the military or as a means of personal transport
Transport
Transport or transportation is the movement of people, cattle, animals and goods from one location to another. Modes of transport include air, rail, road, water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations...
.
German Himmelstürmer of World War II
During World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, Germany made late-war experiments of strapping two wearable shortened Schmidt pulse jet tubes of low thrust to the body of a pilot. The working principle was the same as the Argus As 014
Argus As 014
|-See also:*List of aircraft engines*Republic-Ford JB-2 Loon*Ford PJ31*Chelomey D-3-Bibliography:*Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9...
pulse jet that powered the Fieseler Fi 103 flying bomb (more popularly known as V-1 or buzz bomb), though the size was much smaller.
The device was called "Himmelstürmer" (sky stormer) and operated as follows: when the flier ignited both engines simultaneously the tubes began to pulse modulate. The angled rear tube strapped to the flier's back provided both lift and forward thrust while the chest mounted deflector tube of lower thrust maintained a constant upward thrust. This lifted the flier up and forward. By opening the throttle to the rear tube, calculated "jumps" could be made of up to 60 meters (180 ft) at low altitude (under 50 ft, 15 m). The tubes consumed very little fuel but not much could be carried either.
The intended use for this device was for German engineer units to cross minefields, barbed wire obstacles, and bridgeless waters. The device was never intended for troop use, despite the imaginative depiction of it in that role in the comic book and film The Rocketeer
The Rocketeer
The Rocketeer is a superhero created by writer/illustrator Dave Stevens. The character first appeared in 1982 and is a homage to the Saturday matinee heroes of the 1930s and 1940s....
(which was a prop bearing no resemblance to the real device).
At the end of the war this device was handed over to Bell Aerosystems which tested it on a tether out of fear of harm as no test flier was willing to risk his life with the German machine. What became of the device is not known.
The fictional device used by The Rocketeer was a rocket pack that was technically unique (at least in the film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
adaptation) because it was designed to remain cool. The Himmelstürmer, by comparison, never operated long enough to get extremely hot and both tubes were angled away from the body of the flier. In operation the thrust difference between pulse tubes acted as a push/pull/lift system. Flight time for jumps was in seconds with no lengthy descent time as altitude was minimal. As soon as the throttle was disengaged the device was shut off, a very simple operation and there was no report of any casualties.
Jump Belt
In 1958, Garry Burdett and Alexander Bohr, engineers of ThiokolThiokol
Thiokol is a U.S. corporation concerned initially with rubber and related chemicals, and later with rocket and missile propulsion systems...
Corporation created the "Jump Belt", which they named Project Grasshopper. Thrust was created by high-pressure compressed nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
. On the "belt" were fixed two small nozzles, directed vertically downward. The wearer of the "belt" could open a valve, letting out from the nitrogen gas cylinder
Gas cylinder
A gas cylinder is a pressure vessel used to store gases at above atmospheric pressure. High pressure gas cylinders are also called bottles. Although they are sometimes colloquially called "tanks", this is technically incorrect, as a tank is a vessel used to store liquids at ambient pressure and...
through the nozzles, in this case it was tossed upward to the 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. Then Burdett and Bohr tested a hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
powered version. The "jump belt" was demonstrated by a serviceman in action, but there was no financing, and the matter again did not go to further tests.
Aeropack
In 1959 Aerojet General CorporationAerojet
Aerojet is an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California with divisions in Redmond, Washington, Orange, Gainesville and Camden, Arkansas. Aerojet is owned by GenCorp. They are the only US propulsion company that provides both solid rocket...
won a U.S. Army contract to make a jet pack or rocket pack. At the start of 1960 Richard Peoples made his first tethered flight with his Aeropack.
In 1960, Bell
Bell Aircraft
The Bell Aircraft Corporation was an aircraft manufacturer of the United States, a builder of several types of fighter aircraft for World War II but most famous for the Bell X-1, the first supersonic aircraft, and for the development and production of many important civilian and military helicopters...
Rocketbelt was presented to the public. The jet of gas was provided by a hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
powered rocket but the jet can 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
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
).
Development continues
American servicemen did not lose interest in this type of flight vehicle. Control of transport studies of the U.S. Army Transportation Research Command (TRECOM) assumed that personal jet apparatuses could find the most diverse uses: for reconnaissanceReconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....
, crossing rivers, amphibious landing, access to steep mountain slopes, overcoming minefields, tactical manoeuvring, etc. The concept was named Small Rocket Lift Device, SRLD.
Within the framework of this concept the administration in 1959 concluded with the company Aerojet General
Aerojet
Aerojet is an American rocket and missile propulsion manufacturer based primarily in Rancho Cordova, California with divisions in Redmond, Washington, Orange, Gainesville and Camden, Arkansas. Aerojet is owned by GenCorp. They are the only US propulsion company that provides both solid rocket...
a big contract to research on 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 company Bell Aerosystems 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 send an order for Bell Aerosystems to develop an SLRD. Wendell Moore was appointed as the chief project engineer.
Hydrogen peroxide powered rocketpacks
A hydrogen peroxideHydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
-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 the catalyst (for example, silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
) it decomposes into a mixture of superheated steam
Superheated steam
Superheated steam is steam at a temperature higher than water's boiling point. If saturated steam is heated at constant pressure, its temperature will also remain constant as the steam quality increases towards 100% Dry Saturated Steam. Continued heat input will then generate superheated steam...
and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
in less than 1/10 millisecond
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
increasing in volume 5000 times: 2 H2O2 → 2 H2O + O2. The reaction is exothermic
Exothermic
In thermodynamics, the term exothermic describes a process or reaction that releases energy from the system, usually in the form of heat, but also in the form of light , electricity , or sound...
, i.e. with 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 directly led 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
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 ,...
. Currently, such rocket belts (limited to the amount of fuel the user can carry unassisted) can only fly for about 30 seconds.
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 of the construction of Wendell Moore can be prepared in workshop conditions but needs 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 parachuteParachuteA 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...
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. Due to their strong visual impact, rocket pack flights are guaranteed to seize the attention of spectators. 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
Olympic Games
The Olympic Games is a major international event featuring summer and winter sports, in which thousands of athletes participate in a variety of competitions. The Olympic Games have come to be regarded as the world’s foremost sports competition where more than 200 nations participate...
1984 in Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
, USA
Bell Textron Rocket Belt
Bell Rocket Belt
The Bell Rocket Belt is a low-power rocket propulsion device that allows an individual to safely travel or leap over small distances. It is a type of rocket pack.-Overview:...
is on display at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
's National Air and Space Museum
National Air and Space Museum
The National Air and Space Museum of the Smithsonian Institution holds the largest collection of historic aircraft and spacecraft in the world. It was established in 1976. Located in Washington, D.C., United States, it is a center for research into the history and science of aviation and...
annex, the Steven F. Udvar-Hazy Center
Steven F. Udvar-Hazy Center
The Steven F. Udvar-Hazy Center is the Smithsonian National Air and Space Museum 's annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia, United States....
, located near Dulles Airport.
RB-2000 Rocket Belt
This was a successor to the Bell Rocket Belt. See Bell Rocket Belt#RB2000 Rocket Belt.Bell Pogo
The Bell Pogo was a small rocket-powered platform that 2 people could ride on. Its design used features from the Bell Rocket Belt.Powerhouse Productions Rocketbelt
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 and performed Rocketbelt performances exclusively since 1983, including the 1984 Summer Olympics1984 Summer Olympics
The 1984 Summer Olympics, officially known as the Games of the XXIII Olympiad, was an international multi-sport event held in Los Angeles, California, United States in 1984...
, Carnival in Rio de Janerio, Super Bowls, the Rose Parade and Daytona 500
Daytona 500
The Daytona 500 is a -long NASCAR Sprint Cup Series race held annually at the Daytona International Speedway in Daytona Beach, Florida. It is one of four restrictor plate races on the Cup schedule....
, Michael Jackson
Dangerous World Tour
The Dangerous World Tour was the second worldwide concert tour by American megasuperstar Michael Jackson. The tour, sponsored by Pepsi-Cola, included 69 performances to an audience of 3.5 million. All profits were donated to various charities including Jackson's own "Heal the World Foundation". The...
and many T.V shows including Walker Texas Ranger and NCIS. Powerhouse Rocketbelt pilots include stuntman Kinnie Gibson and Dan Schlund.
Tecnologia Aeroespacial Mexicana
The Tecaeromex Rocket Belt is or was made by Company OathKeeper Inc. ran by vice president Clayton Bruce Reed Tecnologia Aeroespacial Mexicana, which is said to be made by the only company in the world that offers a flying and tested rocket belt package, featured in the March 2006 issue of Popular SciencePopular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
magazine and many TV programs around the world like the Discovery Channel
Discovery Channel
Discovery Channel is an American satellite and cable specialty channel , founded by John Hendricks and distributed by Discovery Communications. It is a publicly traded company run by CEO David Zaslav...
, the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
, ProSieben, TV Azteca
TV Azteca
Azteca, is the second largest Mexican television entertainment. It was established in 1983 as the state-owned Instituto Mexicano de la Televisión , a holding of the national TV networks channel 13 and 7 and was privatized under its current name in 1993 and now is part of Grupo Salinas...
, The Science Channel
The Science Channel
Science is a United States cable, satellite and IPTV Television Network produced by Discovery Communications. Science features programming in the fields of space, technology, prehistory and animals.-History:...
, The History Channel
The History Channel
History, formerly known as The History Channel, is an American-based international satellite and cable TV channel that broadcasts a variety of reality shows and documentary programs including those of fictional and non-fictional historical content, together with speculation about the future.-...
. 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). It runs on hydrogen peroxide
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
. It sells for USA $125,000 including a training course in using it.
TAM has also developed a concept for a backpack helicopter
Backpack helicopter
A backpack helicopter is a helicopter motor and rotor 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, like a parachute harness, should have a strap between the legs, so that the pilot does not...
called Libellula
Libellula
Libellula is a genus of dragonflies, commonly called Skimmers, in the family Libellulidae, distributed throughout the temperate zone of the Northern Hemisphere. Most species are found in the United States, where they are the best-known large dragonflies, often seen flying over freshwater ponds in...
, with a 2-bladed rotor driven by a small rocket motor at the end of each rotor blade.
Jetpack International
Jetpack International made 3 types of jet packs. They do not have wings:| Name | Max flight time | Max distance | Max speed | Max height | Max pilot weight | Fuel | Motor type | Fuel capacity | Price |
|---|---|---|---|---|---|---|---|---|---|
| Jet pack H202 | 33 seconds | 152 m | 112 km/h | 37 m | 81 kg | H2O2 Hydrogen peroxide Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent... |
rocket | 22 litre | Not for sale |
| Jet pack H202-Z | 43 seconds | 457 m | 124 km/h | 76 m | 81 kg | H2O2 Hydrogen peroxide Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent... |
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 incl. training |
A Jet Pack H202 was flown for 34 seconds in Central Park
Central Park
Central Park is a public park in the center of Manhattan in New York City, United States. The park initially opened in 1857, on of city-owned land. In 1858, Frederick Law Olmsted and Calvert Vaux won a design competition to improve and expand the park with a plan they entitled the Greensward Plan...
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.
Externally Powered High Density Propellant
The thrust for jet packs depend on the density of the propellant and the flow rate. Many self contained jetpacks have limited weight restriction which prevents 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".Turbojets
Packs with the turbojet engine work on the traditional keroseneKerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
. They have higher efficiency
Fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
, 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
In 1965 Bell Aerosystems concluded a new contract with the Defense Advanced Research Projects AgencyDefense Advanced Research Projects Agency
The Defense Advanced Research Projects Agency is an agency of the United States Department of Defense responsible for the development of new technology for use by the military...
(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 turbine
Gas turbine
A gas turbine, also called a combustion turbine, is a type of internal combustion engine. It has an upstream rotating compressor coupled to a downstream turbine, and a combustion chamber in-between....
s, worked to design a new turbojet pack. Williams Research Corporation (now Williams International
Williams International
Williams International is a manufacturer of small gas turbine engines based in Walled Lake, Michigan, United States. It produces jet engines for cruise missiles and small jet-powered aircraft.- History :...
) in Walled Lake, Michigan
Walled Lake, Michigan
Walled Lake is a city in Oakland County in the U.S. state of Michigan. The population was 6,999 at the 2010 census.-Origins of the name:The town's name is said to have been given by the first Euro-American settler, Walter Hewitt, in 1825...
, designed and built a new turbojet engine to Bell's specifications in 1969. It was called the WR19, with a rated thrust of 195 kgf
KGF
KGF may refer to:*Keratinocyte Growth Factor*King George's Fields A UK set of 471 memorial playing fields and recreation grounds*Kolar Gold Fields*The IATA code for Sary-Arka Airport, Karaganda, Kazakhstan...
(1,910 newtons) and weighing 31 kg.
The first free flight of the "Jet Belt" took place on 7 April 1969 at the Niagara Falls Municipal Airport
Niagara Falls International Airport
-Traffic figures:Niagara Falls International received 56,943 passengers in 2008. As per Federal Aviation Administration records, the airport had 660 passenger boardings in calendar year 2005 and 1,409 unscheduled enplanements in 2006....
. 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 and go 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
Myocardial infarction
Myocardial infarction or acute myocardial infarction , commonly known as a heart attack, results from the interruption of blood supply to a part of the heart, causing heart cells to die...
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 the technical documentation, to Williams Research Corporation. This pack is now in the Williams International company museum.
A version of this engine went on to power the later US Tomahawk cruise missiles.
Special features of the turbojet pack
The "Jet Belt" used a small turbofanTurbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
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 temperature. 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
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
fuel was in tanks beside the engine. Control of the turbojet pack was similar the rocket pack, but the pilot could not tilt the entire engine. Maneuvering was by deflecting the controlled nozzles. By inclining levers, the pilot could move the jets of both nozzles forward, back, or sideways. The pilot rotated left/right by the 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 higher than 20 meters. This engine went on to become the basis for the early cruise missile propulsion unit.
Space
Extra-vehicular activity
Extra-vehicular activity is work done by an astronaut away from the Earth, and outside of a spacecraft. The term most commonly applies to an EVA made outside a craft orbiting Earth , but also applies to an EVA made on the surface of the Moon...
(EVA) in outer space
Outer space
Outer space is the void that exists between celestial bodies, including the Earth. It is not completely empty, but consists of a hard vacuum containing a low density of particles: predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, and neutrinos....
. While near Earth a jet pack has to produce a g-force
G-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
of at least 1g (otherwise it just provides some steering capacity while falling down), for excursions outside a free fall
Free fall
Free fall is any motion of a body where gravity is the only force acting upon it, at least initially. These conditions produce an inertial trajectory so long as gravity remains the only force. Since this definition does not specify velocity, it also applies to objects initially moving upward...
ing spaceship even a small g-force, for a small deviation from free fall, is already sufficient, hence much less delta-v
Delta-v
In astrodynamics a Δv or delta-v is a scalar which takes units of speed. It is a measure of the amount of "effort" that is needed to change from one trajectory to another by making an orbital maneuver....
is consumed per unit time, and not during the whole EVA. With only small amounts of 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....
needed, safety and temperature are much more manageable than in Earth gravity in the atmosphere.
Rocket packs were tested during mission STS-64. Mission Specialists Carl Meade and Mark Lee tested the SAFER Rocket Pack while Hammond remained inside the Orbiter.
NASA's Manned Maneuvering Unit (MMU) (compressed gas powered)
In the 1980s, NASANASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
demonstrated the Manned Maneuvering Unit
Manned Maneuvering Unit
The Manned Maneuvering Unit is an astronaut propulsion unit which was used by NASA on three space shuttle missions in 1984. The MMU allowed the astronauts to perform untethered EVA spacewalks at a distance from the shuttle. The MMU was used in practice to retrieve a pair of faulty communications...
(MMU), a rocket pack that allowed an astronaut
Astronaut
An astronaut or cosmonaut is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft....
to function as his/her own spacecraft, but the system was retired before the decade was gone. The MMU is the only jet pack of practical importance. Its operational area is outside a space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...
or spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
, where an astronaut can limitedly move independently. The MMU's propulsion was produced by high-pressure nitrogen gas discharged through nozzles (which the MMU has 24 of). The MMU was used since 1984 in three Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
missions (STS-41-B, STS-41-C and STS-51-A).
NASA's SAFER
Recently, NASA has introduced the SAFERSimplified Aid for EVA Rescue
Simplified Aid for EVA Rescue is a small, self-contained, propulsive backpack system used to provide free-flying mobility for a Space Shuttle or International Space Station crewmember during extra-vehicular activity...
, a smaller, simpler version of the MMU meant to be used in case of accidental separation from spacecraft or station.
Winged jet and rocket packs
Visa Parviainen's jet-assisted wingsuit
On 25 October 2005 in LahtiLahti
Lahti is a city and municipality in Finland.Lahti is the capital of the Päijänne Tavastia region. It is situated on a bay at the southern end of lake Vesijärvi about north-east of the capital Helsinki...
in Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...
, Visa Parviainen jumped from a hot air balloon
Hot air balloon
The hot air balloon is the oldest successful human-carrying flight technology. It is in a class of aircraft known as balloon aircraft. On November 21, 1783, in Paris, France, the first untethered manned flight was made by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes in a hot air...
in a wingsuit with two small turbojet jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s attached to his feet. The turbojets provided approximately 16 kgf
KGF
KGF may refer to:*Keratinocyte Growth Factor*King George's Fields A UK set of 471 memorial playing fields and recreation grounds*Kolar Gold Fields*The IATA code for Sary-Arka Airport, Karaganda, Kazakhstan...
(160 N, 35 lbf) of thrust each and ran on kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
(Jet A-1) fuel. Parviainen apparently achieved approximately 30 seconds of horizontal flight with no noticeable loss of altitude.
Yves Rossy's jet wingpack
Yves Rossy
Yves Rossy is a Swiss pilot, inventor and aviation enthusiast. He is the first person to achieve sustained human flight using a jet-powered fixed wing strapped to his back...
developed and built a winged pack with rigid aeroplane-type carbon-fiber wings spanning about 8 feet (2.4 m) and four small kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
-burning jet engine
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s underneath; these engines are large versions of a type designed for model aeroplanes. He wears a heat-resistant suit similar to that of a firefighter
Firefighter
Firefighters are rescuers extensively trained primarily to put out hazardous fires that threaten civilian populations and property, to rescue people from car incidents, collapsed and burning buildings and other such situations...
or racing driver to protect him from the hot jet exhaust
Jet blast
Jet blast is the phenomenon of rapid air movement produced by the jet engines of aircraft, particularly on or before takeoff.A large jet-engined aircraft can produce winds of up to 100 mph up to 200 feet behind it at 40% maximum rated power...
. Similarly, the engines are modified with the addition of a carbon fibre heat shield extending the jet nozzle around the exhaust tail, to further protect the wearer.
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 the midpoint of each wing. 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 using 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...
. 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 the achievement of a precise common alignment during set-up, in order to also prevent instability. An electronic starter system ensures 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 at the opening day of the 35th Exhibition of Inventions at Geneva
Geneva
Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...
. Rossy and his sponsors spent over $190,000 to build the device.
Flights
His first successful trial was on 24 June 2004 near GenevaGeneva
Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...
, Switzerland
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
. Rossy has made more than 30 powered flights since. In November 2006 he flew with a later version of his jet pack.
On May 14, 2008 he made a successful 6-minute flight from the town of Bex
Bex
Bex is a municipality in the canton of Vaud, Switzerland, located in the district of Aigle. It is a few miles south of its sister town municipality of Aigle.-The Bex Salt Mine:Bex is the site of a famous salt mine....
near Lake Geneva
Lake Geneva
Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...
. He exited a Pilatus Porter at 7,500 feet 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.
It has been claimed that the military has been impressed and asked for prototypes for the powered wings, and that Rossy kindly refused the request and stated it is only for aviation enthusiasm purposes.
On 26 September 2008, Yves successfully flew across the English Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
from Calais
Calais
Calais is a town in Northern France in the department of Pas-de-Calais, of which it is a sub-prefecture. Although Calais is by far the largest city in Pas-de-Calais, the department's capital is its third-largest city of Arras....
, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
to Dover
Dover
Dover is a town and major ferry port in the home county of Kent, in South East England. It faces France across the narrowest part of the English Channel, and lies south-east of Canterbury; east of Kent's administrative capital Maidstone; and north-east along the coastline from Dungeness and Hastings...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
in 9 minutes, 7 seconds. His speed reached 186 mph during the crossing, and was at 125 mph when he deployed the parachute.
Current technology
According to the US Government, real jetpacks have little practical value due to the limitations of current technology. The United States Armed ForcesUnited States armed forces
The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...
, which conducted most jet pack research, has declared that 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...
s are far more practical. 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
Hydrogen peroxide
Hydrogen peroxide is the simplest peroxide and an oxidizer. Hydrogen peroxide is a clear liquid, slightly more viscous than water. In dilute solution, it appears colorless. With its oxidizing properties, hydrogen peroxide is often used as a bleach or cleaning agent...
, 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 make their own hydrogen peroxide distillation installations. High concentrated hydrogen peroxide for rocket belts was available from Peroxide Propulsion, Gothenburg, Sweden since 2005, but after a serious accident Peroxide Propulsion is no longer in business.
Two high-profile jet pack projects are currently being operated:
- Jetpack International
- Tecnologia Aeroespacial Mexicana