ANDREW DOYLE / SINGAPORE
Japan's next-generation supersonic transport (SST) research project suffered a setback on 14 July when a rocket-boosted scale model of the aircraft failed to get off the launch pad at Woomera in South Australia.
The 5.5t solid-fuel rocket - which should have propelled the 11.5m-long, 1/10th scale SST model to an altitude of 69,000ft (21,000m) at Mach 2.5 - spiralled out of control and crashed after it prematurely separated from the test vehicle.
"We're going to try and determine what the problem is, rectify it, and carry on with the test programme," says Australian Department of Defence safety operations and liaison officer Peter Nikoloff.
The tests form part of Japan's National Experimental Supersonic Transport (NEXST) programme, which is envisaged as a 300-seat next-generation SST with a range of 10,200km (5,500nm) and a 399,000kg maximum take-off weight. Three more flights are planned over the next 12 months, although it is unclear whether these will take place on schedule.
The first launch was intended as a "systems shake-down", says Nikoloff. The NEXST model is intact, but damaged, and the booster was destroyed.
The flight sequence involves launching the rocket at an elevation of 70° on a 325° heading. The booster should separate 49s into the flight at 69,000ft and M2.5. Readings from instruments mounted on the test vehicle will be taken, first at an altitude of 59,000ft, then at 39,350ft, before the aircraft makes a 180¼ turn about 90km downrange towards the launch site, then executing a serious of sweeping turns to lose altitude and speed. The model is programmed to parachute to an airbag-cushioned landing about 15km from the launch site. Total flight time is about 15min.
The studies are being funded by the Japanese government to prepare the country's industry for a role in any future international collaborative SST programme. Boeing sent engineers to Japan earlier this year to evaluate computational fluid dynamics software developed by Japanese National Aerospace Laboratory that could be applied to Sonic Cruiser pre-development work.
Source: Flight International
