Il domino JETPACK.TV è in vendita
The domain JETPACK.TV is for sale
CLICCA QUI PER CONTATTARCI - CLICK FOR INFO
* E' in vendita solo il nome del domino senza lo spazio web - Is for sale only the name and not web space
ESTIMATED VALUE:
Estimated Value Of Web - Valore stimato dal sito:
appraisalwebdomain.com
NON PERDETE QUESTA OCCASINO - IL VALORE DEL SITO E' DESTINATO AD AUMENTARE NEL TEMPO
Questo è il valore stimato del sito, ma terremo in considerazione qualsiasi offerta.
The following domain name are for sale. We will accept any reasonable offer for them.
SPONSOR:
The domain JETPACK.TV is for sale
CLICCA QUI PER CONTATTARCI - CLICK FOR INFO
* E' in vendita solo il nome del domino senza lo spazio web - Is for sale only the name and not web space
ESTIMATED VALUE:
Estimated Value Of Web - Valore stimato dal sito:
appraisalwebdomain.com
NON PERDETE QUESTA OCCASINO - IL VALORE DEL SITO E' DESTINATO AD AUMENTARE NEL TEMPO
Questo è il valore stimato del sito, ma terremo in considerazione qualsiasi offerta.
The following domain name are for sale. We will accept any reasonable offer for them.
SPONSOR:
The concept of these devices emerged from science fiction in the 1920s and popularised in the 1960s as the technology became a reality. Currently, the only practical use of the jet pack has been extra-vehicular activity for astronauts. Despite decades of advancement in the technology, the challenges of Earth's atmosphere, Earth's gravity, and the human body (which is not well suited for this type of flight) remain an obstacle to its potential use in the military and as a means of personal transport.
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 the 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. 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 reasonably low exhaust velocity and hence a poor specific impulse. 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 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. 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
Fonte del testo prelevato da wikipedia
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 the 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. 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 reasonably low exhaust velocity and hence a poor specific impulse. 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 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. 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
Fonte del testo prelevato da wikipedia