F-35B exceeds STOVL thrust requirement
The F-35B Lightning II short takeoff/vertical landing (STOVL) variant has demonstrated during testing that it produces excess vertical thrust - more than required to carry out its missions. The tests, conducted on a specially instrumented "hover pit," also validated the performance of aircraft software, controls, thermal management, STOVL-system hardware and other systems.
"The performance level measured was absolutely exceptional," said J.D. McFarlan, Lockheed Martin F-35 Air Vehicle lead. "We demonstrated 41,100 pounds of vertical thrust against our requirement of 40,550 pounds.This means we will deliver excellent margin for the vertical landing and short takeoff performance we've committed to our STOVL customers," he said.
The F-35B is powered by a single Pratt & Whitney F135 engine driving a Rolls-Royce lift fan. The F135 is the most powerful engine ever flown in a jet fighter. During hover-pit testing, the aircraft is anchored to a metal grate 14 feet above a sloped concrete floor, separating the jet from ground effect and enabling it to simulate free-air flight. Sensors measure thrust and the aircraft's response to pilot inputs. The testing also demonstrates control of the doors associated with the STOVL propulsion system: engine auxiliary inlet, fan inlet, fan exit, roll posts, and doors that open to enable the Rolls-Royce three-bearing swivel duct to articulate and vector engine thrust. In other tests, metal plates are installed atop the hover-pit grate, enabling engineers to observe and chart the outflow of gases from the propulsion system.