"The performance level measured was absolutely exceptional," said J.D. McFarlan, Lockheed Martin F-35Air Vehicle lead. "We demonstrated 41,100 pounds of vertical thrustagainst our requirement of 40,550 pounds. This means we will deliverexcellent margin for the vertical landing and short takeoff performancewe've committed to our STOVL customers," he said. Those customersinclude the U.S. Marine Corps, the United Kingdom's Royal Navy and Royal Air Force, and the Italian Navy and Air Force.
The F-35B is powered by a single Pratt & Whitney F135 enginedriving a Rolls-Royce lift fan. The F135 is the most powerful engineever flown in a jet fighter.
During hover-pit testing, the aircraft is anchored to a metal grate14 feet above a sloped concrete floor, separating the jet from groundeffect and enabling it to simulate free-air flight. Sensors measurethrust and the aircraft's response to pilot inputs. The testing alsodemonstrates control of the doors associated with the STOVL propulsionsystem: engine auxiliary inlet, fan inlet, fan exit, roll posts, anddoors that open to enable the Rolls-Royce three-bearing swivel duct toarticulate and vector engine thrust. In other tests, metal plates areinstalled atop the hover-pit grate, enabling engineers to observe andchart the outflow of gases from the propulsion system.
The testing demonstrates functional operation of all systemsrequired for vertical flight, and measures the installed forces andmoments on the aircraft during STOVL operations. The hover-pit testsare the final series of ground tests before airborne STOVL testingbegins.
"We've demonstrated critical performance such as inlet pressurerecovery, pitching moment, rolling and yawing moment, effective vectorangles of the exhaust, and control-input response time," said DougPearson, vice president of the F-35 Integrated Test Force. "Each ofthese measurements correlates extremely well with our computer models.The outstanding STOVL performance gives us plenty of confidence tobegin in-flight transitions to STOVL-mode flight and ultimately ourfirst vertical landing at the Naval Air Station Patuxent River, Md.,this summer."
The F-35B is the first aircraft to combine stealth with shorttakeoff/vertical landing (STOVL) capability and supersonic speed. TheF-35 is a supersonic, multi-role, 5th generation stealth fighter. Threevariants derived from a common design, developed together and using thesame sustainment infrastructure worldwide, will replace at least 13types of aircraft for 11 nations initially, making the Lightning II themost cost-effective fighter program in history.
Headquartered in Bethesda, Md., Lockheed Martin is a global securitycompany that employs about 146,000 people worldwide and is principallyengaged in the research, design, development, manufacture, integrationand sustainment of advanced technology systems, products and services.The corporation reported 2008 sales of $42.7 billion.
