Boeing's X-32A Joint Strike Fighter concept demonstrator aircraft (CDA) completed its maiden flight on 18 September, despite a minor hydraulic leak which forced the flight to be cut short. The rival Lockheed Martin X-35A has yet to fly.
The leak, described by Boeing JSF chief test pilot Fred Knox as a "non-event", was reported by a chase aircraft seconds after take-off from Palmdale, California around 08.00 local time. As a precaution, Boeing shortened the flight, which included a basic handling qualities assessment, during the 48km hop to Edwards AFB.
Knox says the X-32A showed "outstanding flying qualities" during the evaluation, which took place at an altitude of 10,000ft (3,000m) and at speeds between 160kt (296km/h) and 200kt. The aircraft used 2,200ft for its take-off roll, rotating at 130kt and becoming airborne at 150kt. Knox maintained 20° pitch angle for climb out and throttled the Pratt & Whitney JSF119 engine back 20% to stabilise airspeed at 210kt with the gear still down. Knox says that the Boeing F/A-18 chase aircraft required "a lot of afterburner" to maintain station with the X-32A during the initial climb. He adds that overall handling qualities are "very similar to the Hornet, because we designed it that way."
About 80% of the planned tests were carried out on the flight, despite the earlier than expected landing. Evaluations were carried out at 11° angle-of-attack (AoA), though the aircraft did reach 13° AoA. Further handling at 15í was among the tests scrubbed because of the precautionary return.
Following initial handling tests, the aircraft was lined up for a 3° approach to Edwards AFB, where it touched down at 155kt in a flared landing. Touchdown speeds for the carrier version (CV) portion of the X-32A tests will be "significantly slower" Knox adds.
Flight tests had been expected to resume on 22 September but high winds at Edward AFB caused their cancellation. The 100h test phase will be divided "around 50:50" between evaluation of CV and conventional take-off and landing handling qualities for the US Navy and US Air Force respectively, says Boeing JSF flight test director, Kate Flemming.
Following the opening of the basic flight envelope, the CV test portion will be tackled first, says Flemming.
Source: Flight International
