Graphic shows key features of Reaction Engines Sabre rocket engine.
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SPACE

Sabre space plane engine

By Duncan Mil

April 16, 2019 - Sabre is an experimental air-breathing rocket engine, designed to power a craft from standstill on a runway to hypersonic flight at over Mach 5 (6,300km/h), before switching over to rocket mode to reach Mach 25 and low Earth orbit.

British-based Reaction Engines has made a technological breakthrough in its efforts to build a plane that can travel to space. The company successfully tested its “pre-cooling” technology, which is critical to cool down compressor delivery temperature when flying at multiples of the speed of sound.

The faster the flow of air into the engine’s intake during high-speed ascent, the higher the temperature. And the heat would rise still further once the airflow is slowed and compressed before entering the combustion chambers -- with the risk of melting the insides of an engine.

The breakthrough test, conducted on March 25 at Reaction Engines’ TF2 test facility at Colorado Air and Space Port near Watkins in the U.S, demonstrated the ability to rapidly chill incoming heated air generated by a General Electric J79 turbojet operating at full military power -- the equivalent temperature experienced at Mach 3.3. The next test will see the J79 operating in full afterburner mode, corresponding to Mach 5.

Reaction Engines’ pre-coolers comprise of 16,800 pipes made of Inconel 718, a high-strength, corrosion-resistant nickel-chromium alloy. The interlaced metal tubes have walls with a thickness of 40 microns -- thinner than a human hair. This pre-cooling technology can cool air from 1,000°C to -120°C in the space of 1/20th of a second.

“This is a hugely significant milestone which has seen Reaction Engines’ proprietary pre-cooler technology achieve unparalleled heat transfer performance,” said the company’s chief executive Mark Thomas.

The lightweight pre-cooler will form the basis of the company’s SABRE (Synergistic Air-Breathing Rocket Engine) space plane.

PUBLISHED: 16/04/2019; STORY: Graphic News
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