|
The advantage of the jet engine is that it efficient for high-speed and high-altitude flight, especially at supersonic speeds. But for other than large commercial or military aircraft a propeller (powered by a [gas turbine]?) is more common. |
|
The advantage of the jet engine is its efficiency at high-speeds (especially supersonic) and high-altitudes. On slower aircraft, a propeller (powered by a [gas turbine]?) is more common. |
|
The gas turbine was the earliest form of jet propulsion unit. The idea was developed independently in England (Whittle?) and Germany ([von Ohain]?). They did not invent the gas turbine but both realised the promise the design held for flight. Whittle filed his first patent in 1930 and ran his first engine in April 1937. Almost a month earlier von Ohain ran an experimental hydrogen powered engine. The first jet aircraft - a Heinkel He-178, flew on 27th August 1939. An English Gloster-Whittle E28/39 flew 21 months later. |
|
The gas turbine was the earliest form of jet propulsion. The idea was developed independently in England (Whittle?) and Germany ([von Ohain]?). They did not invent the gas turbine but both realised the promise the design held for flight. Whittle filed his first patent in 1930 and ran his first engine in April 1937. Almost a month earlier von Ohain ran an experimental hydrogen powered engine. The first jet aircraft - a Heinkel He-178, flew on 27th August 1939. An English Gloster-Whittle E28/39 flew 21 months later. |
|
* Turbojet - the simplest jet engine. It consists of an air intake at the front, a compressor section, a combustion chamber, a turbine (to extract some of the energy of the exhaust to drive the compressor), and an exhaust nozzle. |
|
* Turbojet - the simplest jet engine. It consists of an air intake at the front, a compressor section, a combustion chamber, a turbine (to extract some of the energy of the exhaust to drive the compressor), and an exhaust nozzle. |
|
* Ramjet - When air enters a jet engine its speed decreases and its pressure increases, the ram compression effect. So as an aircraft's speed rises the compressor becomes less and less necessary. At Mach three and above no compressor (or turbine) is needed for efficient combustion. All that is needed is a suitably shaped tube, with a variable internal geometry to create a combustion chamber where fuel is injected. A ramjet thus contains no moving parts and can run much more reliably at supersonic speeds than a turbofan. However ramjets work inefficiently below Mach 3, and not at all from stand still so some kind of booster is required to get the aircraft up to speed. One possibility is a dual-mode turbo-ramjet (the HOTOL space vechicle) but rocket boosters, a drop from a mother ship or even a catapult are more common today. At hypersonic? speeds the compression produced by the shock waves also allows the possibility of an external ramjet - fuel could be injected directly into the airstream and burned, integrating lift and propulsion onto the surface of an aircraft. |
|
* Ramjet - When air enters a jet engine its speed decreases and its pressure increases, the ram compression effect. So as an aircraft's speed rises the compressor becomes less and less necessary. At Mach three and above no compressor (or turbine) is needed for efficient combustion. All that is needed is a suitably shaped tube, with a variable internal geometry to create a combustion chamber where fuel is injected. A ramjet thus contains no moving parts and can run much more reliably at supersonic speeds than a turbofan. However ramjets work inefficiently below Mach 3, and not at all from stand still so some kind of booster is required to get the aircraft up to speed. One possibility is a dual-mode turbo-ramjet (the HOTOL space vechicle) but rocket boosters, a drop from a mother ship or even a catapult are more common today. At hypersonic? speeds the compression produced by the shock waves also allows the possibility of an external ramjet - fuel could be injected directly into the airstream and burned, integrating lift and propulsion onto the surface of an aircraft. |
![[Home]](wikipedia.png)