Jet aircraft

An aircraft which is propelled by jet engines is referred as jet aircraft. Jet aircraft can move faster than sound. Jet aircraft generally flies at higher altitude as high as 10,000 to 15,000 meters as and much faster than propeller powered aircraft. Jet engines at these altitudes gain maximum efficiency over long distances. At much lower altitudes the engines in propeller powered aircraft achieve their maximum efficiency.

The first manufactured turbine jet aircraft was the Heinkel. In late 1929 the first turbine equipped jet aircraft was designed on paper when Frank Whittle of the British Royal Air Force sent his concept to the Air Ministry to see if it would be of any interest to them.

The first operational jet aircraft was the Messerschmitt Me 262, in late World War II made by Germany. Although the rocket powered Messerschmitt Me 163 Komet was faster but still this jet aircraft was the quickest established aircraft of World War II. The Imperial Japanese Navy also developed jet aircraft in 1945, including the Nakajima J9Y Kikka, a crude copy of the Me262.

The fastest air breathing jet aircraft is the unmanned X43 scramjet at around Mach 910. The fastest manned aircraft is the X15 at Mach 6.85. Based on air breathing jet engines most people use the term jet aircraft to denote gas turbine, but scramjets and rockets are both also propelled by them.

US Federal Aviation Administration and NASA have been promoting Very Light Jets: small general aviation aircraft seating 4 to 8 passengers. The speed of sound predominantly depends on air temperature, so the Mach number for the speed of a jet also varies with atmospheric conditions. Modern airliners cruise at speeds of 0.75 to 0.85 Mach, or 75% to 85% of the speed of sound.