The Boeing/EADS X-31 has demonstrated an automated thrust-vectored landing at 24¡ angle of attack (AoA) and 121kt (224km/h), a 31% reduction from the aircraft's normal touchdown speed. The landing, at the US Navy's Patuxent River, Maryland, test centre, completed the three-year US/ German VECTOR extremely short take-off and landing (ESTOL) demonstration programme.
The X-31 typically lands at 12° AoA and 175kt, and requires a 2,400m (8,000ft) ground roll. On the final landing, the pilot required just 520m to slow the aircraft enough to turn a complete circle in the middle of the runway. The ESTOL landings were fully automatic, the X-31 guided to the ground by the differential-GPS integrity beacon landing system, which is accurate to within 2cm (0.8in).
Two thrust-vectoring X-31s were built by Rockwell and MBB for the Enhanced Fighter Manoeuvrability programme, a joint venture between the US Navy, Defense Advanced Research Projects Agency, NASA and Germany, conducted between 1990 and 1995. One crashed and the surviving aircraft was returned to flight in 2001 for the VECTOR programme.
NASA has completed the first phase of the flight testing of a modified Boeing F/A-18 under the Active Aeroelastic Wing (AAW) programme. The AAW project aims to determine the advantages of twisting flexible wings for roll control at transonic and supersonic speeds, and will help design lighter, more flexible high aspect-ratio wings for future combat aircraft. The first phase of testing covered 50 data-gathering flights at altitudes from 5,000ft (1,530m) to 25,000ft and speeds from Mach 0.8 to 1.3. Boeing Phantom Works will use the data to develop control-law software for the second phase of AAW tests, planned for early 2004.Source: Flight International
