Jet packs-A device of transportation in future


         
               



The future is going to be pretty awesome. Each one of us will have our own personal jet pack. Instead of a long, slow daily commute, we'll zip straight to work at 100 mph, skimming along the tree tops. Family vacations will include jet pack trips to scenic locations unmarred by roads. Workers will use jet packs to complete work in high places, such as inspecting bridge supports or even cleaning skyscraper windows.

Wait … weren't we saying this about the future more than 50 years ago? Wh­y has development of the jet pack been so slow? For many, this has been one of life's major disappointments. From the first promising flight tests in the 1940s, jet pack technology has hardly advanced at all. In fact, over the decades, jet packs have simply been unable to overcome some very fundamental problems. But it hasn't been all bad news. Along the way, jet packs have benefitted from several technological advancements, and they've even made a few high-profile appearances in the popular media.

With that said, is there any way that the average person will be able to get their hands on a real jet pack? Is it practical? Is it affordable?



Jet Pack or Rocket Pack?


Most of the ­devices we refer to as jet packs are actually rocket packs, sometimes called rocket belts. The difference between a rocket and a jet is significant. A jet intakes air, compresses it with a turbine and pushes it out the back, mixing it with fuel and combusting it in the process. The oxygen in the air is a key ingredient in the combustion phase, so a jet needs a constant air intake to work. A rocket carries all its fuel and oxidizer (which may be liquid oxygen or some other chemical), mixes them together and combusts them. No air intake is needed.

Turbojet packs



Depiction of a jetpack with folding wings
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. Jet packs and rocket packs have much better flight time on a tankful of fuel if they have wings like an aeroplane's.

Hydrojet packs



Jetlev water powered Jetpack

A Flyboard with its distinctive configuration of having the nozzles located below the pilot's feet
The 21st century has seen a new approach to jet packs where water is used as a high-density propulsion fluid. This requires a very large mass of fluid that makes a self-contained jetpack infeasible. Instead, this approach separates the engine, fuel and fluid supply from the pilot's flying apparatus, using a long flexible hose to feed the water to the jet nozzle pack attached to the pilot's body. These inventions are known as "hydro jet packs", and successful designs have used jetski technology as the powerplant operating in a body of water (an ocean, lake, or pool) to provide the needed propulsion. Several hydro jet pack approaches have been successfully tested and put into production. Flow rate can be controlled by a throttle operator on the jetski, or by the pilot using a remote actuator.

Another significant difference with hydro jet packs is that they can be operated below the surface as well as above it. As of 2013, many hydro jet pack rental businesses are operating in various locations around the world.


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