Boeing's hypersonic plane is in the concept stage but could revolutionise travel. Photo / Supplied
Boeing's hypersonic plane is in the concept stage but could revolutionise travel. Photo / Supplied
A hypersonic aircraft capable of flying from Auckland to Los Angeles in under four hours would ride on a shock wave like a surfboard across the Pacific but passengers would only feel forces similar to commercial planes flying now.
Boeing at the weekend revealed more details of the concept planewhich would fly at up to 5800km/h, 1.6km a second and two and a half times the speed of the Concorde.
Boeing's chief scientist for hypersonics Kevin Bowcott said the aircraft would be made of advanced titanium to withstand heat at high speed and altitudes of 95,000 feet (29km). Parts of the wings would heat up to temperatures exceeding 600C.
The plane would fly more than five times that of subsonic commercial planes flying now but passengers would not feel much difference, he said.
''It will be amazing but it wont' be scary - you don't feel speed.''
At take-off in planes now passengers felt forces equivalent to one-third the force of gravity, for up to one minute, which pushes them into their seats. In a hypersonic plane the forces would be similar but last for 10 minutes as it climbed towards its cruising altitude on the edge of space.
''You'll see the curvature of the earth below you and the blackness of space above,'' Bowcott said, just prior to this week's Farnborough Air Show in Britain where concept models of the plane will be displayed.
Bowcott said although hypersonic technology had been around for more than 50 years, converting it to a viable commercial aircraft programme was still in its early stages.
It could be 20 years or more before the plane is launched and Bowcott said the number of passengers it could carry hadn't been determined.
''It's too early to say — the market will determine what the right number of passengers is,'' he said.
However, massive computing power is accelerating aircraft and engine development in labs, meaning manufacturers can get around to building physical prototypes sooner.
New features of the planned hypersonic plane include:
Being extremely slender and sleek.
''It's also shaped to ride on its own shock wave - the wing creates a shock wave that it rides on like a surfboard - we call that a wave rider.''
The Concorde, a technical triumph but commercial failure, was made out of aluminium, the new plane would be made from advanced titanium. The high-strength metal is already used extensively in parts of airliners now but more of it would be used.
A different engine system.
The hypersonic plane would have combined cycle engines. It would fly up to 2000km/h to 3000km/h with traditional turbo fan engines which push air through with compressors but at higher speeds and altitudes air gets too and would melt engine parts so the plane would also have hot ram jet engines - which use the plane's forward motion to compress air through them.
Bowcott said the engines could run on traditional Jet A1 - kerosene - but Boeing was also investigating liquid methane, which is cold and could be used for cooling other parts of the plane.
Tackling the sonic boom
Concorde was banned from many cities because of the sonic boom created when aircraft fly faster than the speed of sound. Bowcott said could be possible that if the boom level was not be reduced low enough it could be relegated to use over the sea only.
At the moment supersonic commercial planes can't fly over the United States. However, Bowcott said Boeing was working with NASA which was developing technology to take the boom level down to a low rumble like thunder in the distance.
An Air France Concorde takes off after a brief stop at Auckland in 2000. Photo / Martin Sykes
Boeing is one of several US plane makers wanting to revive commercial travel faster than the speed of sound. Aerion is developing a 12-seat business jet, Boom is working on a 55-seat plane and Spike is working on a business jet it hopes will enter service in the 2020s.
Concorde flew from 1976 to 2003, when it was permanently grounded after being banned from cities, a crash in 2000 and a drop-off in demand for premium travel, following the 9/11 terror attacks.
Bowcott worked on the hydrogen-powered X-43A scramjet, the fastest aircraft on record which reached speeds of Mach 9.6 in 2004, or just under 10 times the speed of sound.
A scramjet is an air-breathing engine that requires no turbo-machinery; instead, it uses vehicle motion to compress ingested air before burning the supersonic airstream.
Boeing says he also led the conceptual design and optimisation of the X-51A WaveRider, an unmanned, experimental vehicle that relied on its own shock waves for compression lift and set the record for the longest air-breathing propelled flight at hypersonic speed—it flew on scram jet power for 3.5 minutes at Mach 5.1 in 2013.
