A Mach-5 (3,400mph) plane from Reaction Engines A2, carries 300 passengers, fly twice as fast and at the same time be greener for the skies. Funded in part by the European Union’s Long-Term Advanced Propulsion Concepts and Technologies project (Lapcat), the airliner is desired to fly from Brussels to Sydney in less than four hours without producing a trace of harmful carbon emissions.
The A2 engine uses two modes, a combination of turbojet and ramjet propulsion systems, make the A2 efficient at slower speeds while giving it great speed capabilities. In the first mode, four Scimitar engines send incoming air through bypass ducts to turbines which produce thrust comparable to conventional jet engines and get the jet into the air to Mach 2.5. After it reaches Mach 2.5, the A2 switches into the second mode and incoming air is rerouted to the engine’s core. The air gets pushed through the engine with enough pressure to sustain combustion speeds of up to Mach 5.
It’s carbon footprint stands to be the biggest asset to the hydrogen-powered jet. It only produces water vapor and just a bit of nitrous oxide as exhaust. A hypersonic jet loaded with liquid hydrogen sounds a bit dangerous, but hydrogen fuel is no more explosive than normal jet fuel.
The biggest challenge they face is manufacturing hydrogen fuel on a large scale without emitting carbon in the process. Reaction Engines’s technical director, Richard Varvill, is hesitant to market it as a truly green machine till carbon-free production of hydrogen is reached.