Before Concorde was discontinued, the ‘supersonic’ aircraft was able to complete the trans-Atlantic London to New York flight route in less than 3.5 hours. The trip currently takes around 7 hours on a standard jumbo jet. But a recent breakthrough in the latest technology in the world of jet engines made by British aerospace company Reaction Engines could mean future ‘space planes’ are able to make the same journey in just a single hour.
The Concorde, whose Mach 2 speed broke the sound barrier, was dropped because there simply wasn’t enough demand for tickets, which were £4350 one-way and over £8000 for a return. The fatal Concorde crash of Air France flight 4590, caused by the plane running over debris on the runway at take-off, was the final nail in the coffin for demand, despite the fact it was the only accident in the plane’s 27-year history.
However, the new technology being developed by Reaction Engines promises to be far more cost efficient. It combines the fuel efficiency of a jet engine with the power and speed of a rocket. The key innovation to the ‘Sabre’ engine Oxfordshire-based Reaction are working on is a technologically advanced cooling system.
Air is a necessary part of how a jet engine works. Sucked in at the front with a fan, a compressor then raises the pressure of the air which is then compressed by spinning blades. The compressed air sprayed with fuel and ignited by an electric spark with the burning gases blasted out of the nozzle via the turbine.
But when the plane hits higher speeds, the air coming into the jet engine heats up too much, causing the engine to melt. That is the most significant bottleneck to fuel efficient jet engine technology being able to achieve higher speeds safely. Reaction Engine’s system uses a ‘pre-cooler’ that has now been demonstrated to work effectively during tests in Colorado.
The pre-cooler system is tens of thousands of tubes, each finer then a human hair. Filled with liquid helium, they spread over the surface area hot air passes over as it is sucked into the engine. The system is able to cool the air from an engine-melting 1000 0C to room temperature in just one twentieth of a second.
Rocket engines get around the problem by igniting rocket fuel with oxidant. However, this system requires pricier rocket fuel, in greater quantities. The expense further compounded by the fuel oxidant, which itself adds significantly to the weight of the rocket and the amount of fuel it needs to burn to lift off and get into orbit. The Sabre engine is, then, like an ‘air breathing rocket engine’.
It is hoped the technology will in future be applied both to ‘space planes’ able to travel at 3 times the speed of sound as well as actual rockets, hugely reducing the cost of lifting loads into space. A third potential application of the pre-cooler technology is to cool the batteries of future hybrid electric planes it is expected will become the future standard for short-haul flight.
Reaction Engines’ chief executive Mark Thomas commented on the promising test results:
“If you can pull it off, it’s a game changer. It kicks conventional rocket engines into touch.”
Observers have likened the future perfection of Reaction’s Sabre engine technology as a potential ‘new Whittle moment’. Sir Frank Whittle invented the turbojet in the 1930s, a development which launched modern aviation.
Reaction Engines’ was formed in the 1980s by Alan Bond, a lead engineer on the HOTOL spaceplane project – a joint venture of BA and Rolls-Royce that shut down when the UK government cut its funding. Bond subsequently founded React Engines, which now counts BAE Systems, Boeing HorizonX and Rolls-Royce among its investors.