5-hour Europe flight step closer

The A2 is now entering the second phase of tests backed by the European Union. Photo / Supplied

A hypersonic passenger jet has entered its second phase of tests, bringing the dream of trips of less than five hours between Australasia and Europe closer to reality.

The A2 is a 300-seat aircraft capable of non-stop flight to the other side of the planet at a cruising speed of Mach 5, or five times the speed of sound, about 5600km/h.

A Boeing 747-400 takes the better part of 24 hours to fly from Auckland to London, at a top speed of 1000km/h.

The A2 is entering the second phase of a European Union-backed study, due to end in two years.

The British company Reaction Engines began the project before the the supersonic Concorde was grounded seven years ago.

"The objective was to design an aircraft that could travel from Brussels to Sydney in just a few hours," says Reaction technical director Richard Varvill. "Our studies showed the A2 would do it in 4.7 hours.

"We calculated that the ticket price would be about the same as today's typical business-class flight, which is not too bad," says Mr Varvill.

"But the question is how to make it commercially viable and to also make it environmentally acceptable. There are still doubts about whether an aircraft flying at such an altitude would damage the ozone layer."

To provide the range that would allow it to travel non-stop, such an aircraft would, he says, need to be fuelled by liquid hydrogen.

On the downside, this is expensive and would require a global supply structure. But it is carbon dioxide emissions-free and that structure might prove the launch pad for all aircraft to switch to liquid hydrogen.

"The bottom line is that a large, long-distance supersonic passenger jet is looking very promising in terms of technical feasibility," says Mr Varvill.

The A2 will probably not take to the skies before 2030, but supersonic flight may be back on the agenda for a select few within five years.

At US$80 million ($109 million) a pop, Nevada-based research company Aerion Aviation's Supersonic Business Jet is not cheap but it still has US$4 billion in advance orders.

While much of the design is conventional, its proprietary "laminar-flow" technology means it could cross the Atlantic in just two hours.

The company is in talks with manufacturers and hopes to have a deal signed by the end of next year.

"The changes in technology since Concorde are such that the economics of building and getting a meaningful return on supersonic aircraft is that much more feasible," says Aerion vice-chairman Brian Barents.

"As an industry, we already have larger and more comfortable jets, but we're still providing aircraft that fly at the speed they did in the 1950s," says Mr Barents. "Speed is the next frontier. And business jets are a stepping stone to ... commercial jets."

The biggest obstacle to supersonic passenger flight is the sonic boom, the bang created by pressure waves around a plane as it passes through the sound barrier.

- INDEPENDENT