Lockheed Martin's first F-35B short take-off and vertical landing Joint Strike Fighter has rolled off the final assembly line at Fort Worth, Texas to enter ground testing that will lead to a first flight scheduled for May 2008.
The roll-out was attended by representatives of the customers for the STOVL version of the F-35 Lightning II: the US Marine Corps, UK Royal Air Force and Royal Navy and the Italian air force and navy.
Marine Corps Commandant Gen James Conway said the supersonic STOVL JSF will "enable us to operate a fleet of fighter/attack aircraft from the decks of ships, existing runways or unimproved surfaces at austere bases. We find that capability extremely valuable."
Conway: F-35B's capability "extremely valuable" © Lockheed Martin
Compared with the conventional take-off and landing F-35A already flying, the F-35B has a shaft-driven lift fan mounted behind the cockpit, roll ducts installed in the wing and swivelling nozzle fitted to the engine.
In STOVL mode, doors open above and below the lift fan, a clutch engages to drive the two-stage contra-rotating fan from the engine and the rear nozzle pivots downward to deflect engine thrust.
Flight control on vertical-lift mode is provided by vanes in a variable-area box nozzle beneath the lift fan, the roll ducts in the wing and the three-bearing swivelling nozzle. Deployment and stowing of the lift system is automatic.
Initial F-35Bs will be powered by Pratt & Whitney's F135, producing some 40,000lb of thrust in vertical-lift mode. The General Electric/Rolls-Royce F136 alternative engine will make its first flight in the F-35 in 2010. R-R produces the lift system, including the lift fan.
F-35B lift system © Rolls-Royce
The first F-35B, aircraft BF-1, is planned to begin tethered testing on the hover pit at Fort Worth early in 2008. Flight testing is to begin in mid-2008 with conventional take-off and landings, progressing to short take-off and vertical landings.
Long-lead funding for the first six production F-35Bs has been authorised, with deliveries to the US Marine Corps for training planned to begin in 2011. Initial operational capability of the STOVL JSF is scheduled for 2012.
The F-35B will replace both the supersonic Boeing F/A-18 Hornet and STOVL Boeing/BAE Systems AV-8B Harrier II in USMC service, while it will also replace Harriers and other aircraft operated by Italy and the UK.
© Lockheed Martin