Heat exchanger tubes from Fine Tubes play vital part in successful pre-cooler tests for space plane Skylon

At the recent Farnborough Airshow Reaction Engines announced that their revolutionary Skylon space plane has passed another significant milestone following the second phase of successful tests on the Sabre engine pre-cooler.

The high precision heat exchanger tubes manufactured by Fine Tubes are a key component to the cooling system of this hybrid engine which is on course to transform not only space travel but also air transport around the world.

The SABRE engine developed by Reaction Engine and a team of over 30 British engineers has the ground-breaking ability to operate as a jet and rocket engine. This hybrid function will be capable of propelling the space plane Skylon at up to five times the speed of sound allowing a new generation of aircraft to fly to any destination on Earth within four hours or when in rocket-mode directly into space at twenty five times the speed of sound.

With the recent second series of testing Reaction Engines in Oxfordshire has proven the pre-cooler’s aerodynamic stability and uniformity, its structural integrity, freedom of vibration across a wide range above and beyond the flight envelope as well as preliminary cryogenic cooling.

Critical to the performance of the SABRE engine is a pioneering heat exchange system which cools air for the engine intake. This innovative technology will chill incoming hot air from over 1,000°C to minus 150°C in less than 1/100th of a second, enabling the space plane to effectively double the current limits of jet engine speeds.

Fine Tubes’ team of engineers and metallurgy experts in Plymouth has been instrumental in developing crucial tubes for the pre-cooler system and has worked in partnership with Reaction Engines to come up with a breakthrough in aerospace heat exchanger design. “Like the SABRE engine itself, the tubing in its heat exchanger is an engineering marvel”, explains Alan Bond, the company’s corporate programmes director. “There are a few other companies which produce the kind of high technology tube we need but the Fine Tubes product is extremely high quality, meeting all the project specifications. We are very pleased with its performance.”

Each engine uses over 2000km of tubing which has to be extremely thin to minimise weight and to act effectively as a heat exchanger, but also very strong because of the heat, pressure and forces involved. Fine Tubes specially designed a high pressure tube made from Inconel, a nickel alloy that is very resistant to temperature and well suited for use in extreme conditions. The high specification tubes for this pre-cooler system have an outside diameter of less than a millimetre and a wall thickness of just 40 microns, whilst maintaining structural integrity at extreme conditions.

UK Science Minister David Willetts recognised the significance of the Skylon development when he visited the Farnborough International Air show last week: "The engine being developed by Reaction Engines is a potential game-changer in terms of space technology. This successful testing validates the assessment made of the engine concept by the UK Space Agency back in 2010 and is yet another example of the UK’s world class space industry. It would be a fantastic achievement if we could one day use this home-grown technology for our own commercial space launches."

The third and final series of testing will start in August 2012, with the pre-cooler operating at temperatures of -150 °C.

Fine Tubes Ltd. has been supplying the aerospace industry with high performance tubes for over 50 years and the has a proven track record in turning the design concepts of today into the industry standards of tomorrow. The company’s hydraulic or mechanical aerospace tubes are generally used in airframes, aircraft engines and instrumentation, where pilot and passengers equally rely on them to withstand the most critical conditions.