Initial pilot reaction to the Lockheed Martin/Boeing F-22 Raptor is that is an aircraft "quick in roll and acceleration, yet very stable with excellent control" in formation flying and approach configuration, says chief test pilot Paul Metz.
Describing the 58min first flight on 7 September, Metz says that the F-22 rotated at 140kt (260km/h) and "-stopped at 12í, right where I wanted it" for the shallow climb-out, during which it accelerated to 210kt. As the aircraft climbed to 15,000ft (4,600m), the "-amount of buffet on the airframe was surprisingly high", adds Metz, who says that the test team suspects the gear and "particularly flaps".
Performance of the Pratt & Whitney F119 engines was flawless. "I didn't even think about them," he says. The aircraft was put through bank-to-bank manoeuvres producing a "jerky response with some sideways acceleration". Once initial handling evaluation with gear down had been completed, the undercarriage was raised and the F-22 climbed to 20,000ft for evaluation at speeds of up to 250kt.
With gear up, the aircraft "-becomes very clean and quiet", says Metz, who adds that the aircraft "-is very quick in roll and accelerates much quicker than the [Boeing] F-15. Formation flying was a real delight. The aircraft is very well behaved, with Level 1 flying qualities in formation. I felt very comfortable within minutes."
The gear was then lowered, along with the flaps, for a simulated powered approach during a descent to 15,000ft. "The aircraft was still stable and control was excellent, even better than an F-15", he adds. Following completion of this task, the aircraft was flown back to Lockheed Martin's final-assembly plant in Marietta, Georgia, for landing. "I was able to hold speed very precisely to ±1kt using the head-up display on final approach," says Metz, who "-flared it and floated it on at 120kt holding the nose up".
Modifications are being made to small air-cooling intake slots in the diverter ducts near the base of the engine inlets as a result of the first flight after an air-cooling icon advisory illuminated on the caution display. Flight-control software modifications are also expected to overcome the roll ratcheting which was experienced.
The F-22 will be transported to Edwards AFB, California, early in 1998 to begin a 5,000h flight-test programme which will involve nine aircraft over four years.
Source: Flight International
