Boeing's Joint Strike Fighter Program on Track

After being the first of the competing STOVL Joint Strike Fighter demonstrators to transition from conventional to short-takeoff/vertical landing mode, Boeing's X-32B has entered the final phase of its flight-test program to validate its direct-lift approach.

The X-32B's first flight on March 29 marked the aircraft's entry into a four-month test program that will include approximately 55 flights totaling about 40 hours. Prior to entering this next phase, the aircraft completed 14 flights for 14.1 hours at Edwards Air Force Base. Expected milestones in the coming weeks include the first hover and vertical landing of the X-32B.
Boeing built only two JSF demonstrators for the three separate flight test programs: conventional takeoff and landing, carrier operations and short-takeoff/vertical landing. Underscoring the commonality of its JSF design, Boeing used its X-32A aircraft to demonstrate both aircraft-carrier and conventional-takeoff-and-landing objectives. Lockheed Martin built three separate JSF demonstrators.

Commonality is one of the three flight-test objectives mandated by the armed services considering the JSF, the other two being low-speed/carrier approach handling qualities and STOVL.

The X-32A completed its flight-test program in early February after 66 flights and 50.4 flight hours. The flights were split approximately 50-50 between carrier-based and conventional takeoffs and landings.

Boeing calls its direct-lift solutions for the STOVL X-32B a "third-generation" approach. The propulsion design provides for both conventional and vertical flight using a two-dimensional, flow-blocking cruise nozzle coupled with a direct-lift nozzle system. It shifts to the vertical landing mode by redirecting unaugmented engine thrust downward through nozzles to produce lift.

Boeing says its STOVL propulsion system minimizes moving parts, which increases reliability and maintainability and reduces support costs. It calls the approach "low risk" because it is similar to that employed on the AV-8B Harrier.

Boeing's two main partners on the JSF program are Pratt & Whitney for the F119 engine and Rolls-Royce for STOVL components, including the lift nozzles. The single F119 derivative reheated turbofan has 2D thrust vectoring of up to 40,000-pounds-thrust in reheat.
Visually, Boeing's JSF is less traditional than Lockheed Martin's JSF design. The Boeing JSF can be described as stubby with a deep fuselage, with a prominent chin intake and steeply canted twin fins. It has a very broad mainplane and no tail horizontal surfaces.

The USAF plans to buy 1,763 conventional takeoff and landing aircraft to replace A-10s and F-16s, and to complement the F-22 Raptor. The U.S. Navy wants 480 carrier-based JSFs to replace the A-6 and complement the F/A-18E/F Super Hornet. The U.S. Marine Corps plans to acquire 609 STOVL aircraft to replace its AV-8Bs and older-generation F/A-18s. The UK Royal Navy and Royal Air Force require a STOVL aircraft to replace their aging Sea Harrier and GR.7, respectively. The Royal Navy will purchase 60 and the RAF plan to buy 90 aircraft.
The UK has put $2 billion toward the JSF program, giving it an 8% share of the engineering, manufacturing and development phase of the program.

Sales beyond the U.S. and UK could amount to another 3,000 aircraft.

The winner-take-all contract is expected to be announced in October.