Jet pack
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A jet pack is an as-of-yet fictional device, usually worn on the back, that uses jets of escaping gases to allow the user to fly. The name is also a byword for numerous other devices with differing designs but the same function.
Such items have long been a staple of science fiction used by such characters as The Rocketeer and James Bond; while many in the real world have worked on devising a functional jet pack, they have met with limited success. Currently the most advanced designs are more similar to helicopters than jets with an American company working towards a prototype of this model.
While jet packs may appear appealing, they have little practical value. The United States Military, which conducted most jetpack research, has declared that helicopters are far more practical.
Similar devices
Similar to jetpacks are rocket packs, which employ rocket power for lift. Devices along these lines have been made using the engines from cruise missiles, but they are extremely dangerous and difficult to control and have never been flown. The heat from the rockets also tends to be too great. The fictional device used by The Rocketeer was a rocket pack that was important (at least in the film adaptation) because it was designed to remain cool.
In the 1960s, Bell Aerosystems built a device it called a rocket belt using hydrogen peroxide as fuel. This concept was revived in the 1990s and today these packs can provide powerful, but manageable thrust. The great disadvantage is the limited amount of fuel that can be carried, currently only enough to fly for about 30 seconds. This was the style of device used by James Bond.
Rocket packs can be useful in space where much less thrust is needed. 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 gone. Recently, NASA has introduced the SAFER, a smaller, simpler version of the MMU meant to be used in case of accidental seperation from spacecraft or station. With only small amounts of thrust needed, safety and temperature are much more manageable then in the atmosphere.
External links
- http://www.rocketbelt.nl (http://www.rocketbelt.nl/)
- Solotrek XFV description (http://www.unrealaircraft.com/qbranch/solotrek_xfv.php)