Boeing reveal hypersonic passenger jet concept

Boeing unveiled its first passenger-carrying hypersonic aircraft concept at the American Institute of Aeronautics and Astronautics conference in Atlanta this week.

Boeing says the passenger concept could have military or commercial applications and is just one of several hypersonic vehicle concepts spanning a wide range of potential applications company engineers are studying.

Engineers are working company wide to develop enabling technology that will position the company for the time when customers and markets are ready to reap the benefits of hypersonic flight.

Hypersonic planes will be capable of flying at Mach 5 (6174 km/h) or 3,900 miles per hour, about eight times the present commercial airliner cruise speeds.

With a projected altitude of 95,000 ft, the hypersonic jetliner will be 2.5 times faster than the Anglo-French Concorde supersonic airliner retired in 2003.

Boeing believes an advanced titanium airframe will be required to achieve the Mach 5 cruise speed, while the Concorde achieved Mach 2 with an aluminum airframe.

The propulsion system will be a turboramjet engine, a turbofan engine that can transition to ramjet mode.

With a common inlet and exhaust nozzle, turboramjet's turbofan engine will operate until the transition speed required for the ramjet to operate is achieved and will be restarted when the vehicle slows down for a runway landing.

Boeing says a hypersonic passenger vehicle could be airborne in 20 to 30 years.

Boeing, Rolls-Royce and BAE Systems has invested about $37.4 million in the SABRE hybrid aircraft engine being developed by UK based Reaction Engines Ltd.

The SABRE engine would breathe air at lower altitudes for a top speed of around Mach 5, but then switch to a Mach 25 rocket mode when it reaches thinner altitudes at the edge of space.

Ground testing of SABRE is planned for 2020.