Passengers will be able to fly between Paris and Tokyo in 2.5 hours, at least that is the picture of the future EADS paints as it unveils its idea for a hypersonic passenger aircraft.
The hypersonic commercial aircraft, aimed at the premium passenger sector, should be able to transport 50-100 people.
The so called Zero Emission Hypersonic Transportation (Zehst) system notionally should fill the high-end market niche left unmet since the retirement of Concorde, says Jean Botti, chief technical officer at EADS.
Technology underpinning Zehst still would require some time to mature, with a commercial offering not expected to emerge until around 2040, but Botti says an unmanned technology demonstrator could already be flying in about ten years to help validate the concept. EADS officials are not pushing a military application, but acknowledge that may be possible.
Zehst would use three different propulsion systems. The aircraft would take off powered by two turbofans and undertake a steep climb reaching around Mach 0.8 at which point two rocket boosters would kick in to propel the vehicle to Mach 2.5 at which point two underwing ramjets would kick in to reach speeds above Mach 4. Cruising altitude would be just above the atmosphere. The aircraft would glide during decent, with the turbofans powering up again in the final stage of flight.
Despite the use of three propulsion systems, Botti argues the system will not be cost prohibitive. “I am not sure that this equation will be that expensive,” he says, noting that does not mean it would be cheap either. One reason is that the rocket motors are relatively small, merely aimed at giving the aircraft a boost, rather than lifting the entire vehicle from a standing start. “I don’t think it is that complex,” Botti says of the system.
The maximum acceleration the passengers would be exposed to is around 1.2g. Botti says one of the program goals is to minimize emissions and also limit the impact of the sonic boom by trying to direct it to have a small footprint on the ground.