The focus of flight tests of the Lockheed Martin/Boeing F-22 Raptor have been switched to acoustic and load tests of the weapon bays. This follows the initial expansion of the flight envelope to speeds above 560kt (1,040km/h) and altitudes "higher than 50,000ft [15,250m]" says Lockheed Martin F-22 chief test pilot Paul Metz.

The test team also achieved an angle of attack of 60° during flight tests at Edwards AFB, California, in late September. The aircraft had been gradually worked up to the higher angles, having achieved post-stall manoeuvres at 45° - around 15° above the maximum of most current combat aircraft. The aircraft "has a few oddities, but predictable handling" at 60°, says Boeing F-22 chief test pilot Chuck Killberg. "The flight vector was really vertical at that point, but it can roll and stop wherever you point the nose," he adds.

The weapon bay tests will include opening and closing the main and side bays, and extending the launchers with Raytheon AIM-9 Sidewinder and AIM-120 AMRAAM "shapes" on them. The tests, conducted at subsonic and supersonic speeds, follow initial trials which showed "that the handling qualities were just fine with, and during, the extension", according to Killberg.

Another impending milestone for the F-22, coming up later this month, will be the starting of the engines and auxiliary power unit of the third F-22 at Lockheed Martin's Marietta site in Georgia. The aircraft is due for its first flight on 16 February. It will be ferried to Edwards, where it will join the test programme. The fourth test aircraft, the first avionics test vehicle, is set to join the test programme around June.

Source: Flight International