Monday, July 2, 2012

Hypersonic Aircraft

Army and Weapons | Hypersonic  Aircraft |  Well this is the information about Hypersonic  Aircraft, this is a history of Hypersonic  Aircraft are Hypersonic flight is flight through the atmosphere at speeds above about Mach 5.5, a speed where disassociation of air begins to become significant and high heat loads exist. Hypersonic flight has been achieved by the Space Shuttle's orbiter, the Apollo command module, Buran and scramjets. The V-2 rocket, first used in World War II by the Germans and later used by the United States in its early rocketry work, was the first manufactured object to achieve hypersonic flight. In February 1949, its upper stage reached a maximum velocity of 5,150 miles per hour (8,288 kilometers per hour) bmore than five times the speed of sound Template:Altitude needed. 

The vehicle, however, burned on re-entry, and only charred remnants were found. In April 1961, Russian Major Yuri Gagarin became the first human to travel at hypersonic speed, during the world's first piloted orbital flight. Soon after, in May 1961, Alan Shepard became the first American and second person to achieve hypersonic flight when his capsule reentered the atmosphere at a speed above Mach 5 at the end of his suborbital flight over the Atlantic Ocean. In June, Air Force Major Robert White flew the X-15 research airplane at speeds over Mach 5, and broke his own record in November, reaching Mach 6.7.
Launched from a standard runway, a hypersonic aircraft could fly faster than Mach 5 to strike anywhere in the world within two hours. It would also have enough thrust to deliver a satellite to low-Earth orbit. How they work: To get off the ground from a runway, a hypersonic plane would either hitch a ride on a conventional plane, or have its own conventional jet engine. That engine would carry the hypersonic craft to an altitude where air density and resistance are less. Here it would reach supersonic speeds and then shift to its scramjet engine. The scramjet scoops up air and mixes it with fuel so it burns as the mixture flows through the engine at supersonic speeds. This means scramjets can achieve some of the speed of a rocket without having to carry heavy oxidiser (to mix with fuel), as rockets do.

The technology is immature, with many engineering issues unresolved. Scramjets engines can not start until the plane flies faster than the speed of sound. Plus, hypersonic flight has so far only been demonstrated for small unpiloted craft carried to high speed by other vehicles - and other planned experimental craft are too small to carry a pilot.