The ATREX engine developed in Japan is an experimental precooled jet engine that works as a turbojet at low speeds and a ramjet up to mach 6.0. A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... Jet engine diagram Turbojets are the simplest and oldest kind of general purpose jet engine. ... Small ramjet engine A ramjet, sometimes referred to as a stovepipe jet, is a type of jet engine. ... Mach may refer to: Ernst Mach Mach number, as a measure of speed inertial mass GNU Mach The microkernel on which GNU Hurd is based Mach kernel, an operating systems kernel technology used in Mac OS X Mach band, an optical illusion Mach Five, the name of the car in...

ATREX uses liquid hydrogen fuel in a fairly exotic single-fan arrangement. The liquid hydrogen fuel is pumped through a heat exchanger in the air-intake, simultaneously heating the liquid hydrogen and cooling the incoming air. This cooling of the incoming air is critical in achieving a reasonable efficiency. The hydrogen then continues through a second heat exchanger positioned after the combustion section, where the hot exhaust is used to further heat the hydrogen, turning it in a very high pressure gas. This gas is then passed through the tips of the fan providing driving power to the fan at subsonic speeds. After mixing with the air, the hydrogen is burned in the combustion chamber. LH2 is an acronym used in the aerospace industry, which stands for liquid hydrogen. ... A heat exchanger is a device for transferring heat from one fluid to another, where the fluids are separated by a solid wall so that they never mix. ... Combustion or burning is a chemical process, an exothermic reaction between a substance (the fuel) and a gas (the oxidizer), usually O2, to release heat. ... Subsonic has two possible meanings: A speed lower than the speed of sound is called subsonic. ...

External links

• [1] - Official ATREX project site (English version)
• [2] - Official ATREX project site (Japanese version)