F-35B JSF takes to the sky

Aviation Week

Lockheed Flies First STOVL JSF

Jun 12, 2008

Graham Warwick

Lockheed Martin has flown the first short-take-off-and- vertical-landing (STOVL) F-35B, in conventional-take-off (CTOL) mode, clearing the way for funding to be released for production of the first six U.S. Marine Corps aircraft.

The 44-minute flight of aircraft BF-1, the first production-representive F-35, from Lockheed’s Fort Worth, Texas, plant also marked the start of a five-year, 5,000-plus test program involving three variants of the Joint Strike Fighter: the CTOL F-35A, STOVL F-35B and aircraft carrier-capable F-35C.

F-35B lead test pilot Graham Tomlinson, from JSF industrial partner BAE Systems, says the first flight went “absolutely to plan.” Flight-testing is beginning in CTOL mode, with STOVL testing now scheduled to begin in the first quarter of 2009.

The aircraft was flown with gear down at speeds up to 230 knots and 15,000 feet altitude to assess handling qualities. The gear will be retracted on the second flight. Tomlinson says BF-1 flies “very similarly” to aircraft AA-1, the first F-35, with some enhancing features, including dual nose-gear doors to improve directional stability and improved flight control on touchdown. “The aircraft lands itself,” he says.

First flight of BF-1 is one of two milestones required for the award of a $1.3 billion contract for the first six low-rate-initial-production F-35Bs. Marine Brig. Gen. David Heinz, deputy head of the Joint Strike Fighter program office, says the contract should be awarded after Pentagon acquisition chief John Young has been briefed on resolution of blade-failure issues with the STOVL version of Pratt & Whitney’s F135 engine.

Despite the engine problems, the first flight was within weeks of the late May date committed to in August 2006, Heinz says. Although a delay of 30 to 60 days had been predicted after turbine blade failures in two STOVL F135s during ground testing in 2007, “we came in two weeks in front of that,” he says.

Although BF-1 is flying in CTOL mode for now, Tomlinson says the aircraft automatically performs a complete self-check of the STOVL system before flight, including opening all the doors and “waggling the nozzle a bit.” He says the aircraft is fully configured for STOVL, noting that two complete conversions from CTOL to STOVL mode were completed during tie-down hover pit testing leading up to first flight.

F-35B integrated test team lead Doug Pearson says Lockheed will begin “up and away” conversion testing in the fourth quarter, opening the doors in flight in preparation for STOVL “build-down” tests. Over a series of 20 flights, the aircraft will be progressively slowed down in flight, culminating in slow landings at Fort Worth. BF-1 will then relocate to the Navy’s Patuxent River test center in Maryland to perform the first, full vertical landing.