MehrotraPrince
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Pentagon lowers F-35 performance bar
The US Department of Defense is lowering the performance bar for the Lockheed Martin F-35 Joint Strike Fighter according to a new report by the Pentagon's director of operational test and evaluation (***&E).
The specifications for all three variants pertaining to transonic acceleration and sustained turn rates have been reduced. Worst hit in terms of acceleration is the US Navy's F-35C carrier-based model.
"The program announced an intention to change performance specifications for the F-35C, reducing turn performance from 5.1 to 5.0 sustained g's and increasing the time for acceleration from 0.8 Mach to 1.2 Mach by at least 43 seconds," reads the report prepared by J Michael Gilmore, the Pentagon's ***&E. "These changes were due to the results of air vehicle performance and flying qualities evaluations."
The US Air Force F-35A's time has slipped by eight seconds while the US Marine Corps short take-off vertical landing (STOVL) F-35B's time has slipped by 16 seconds. However, turn rates for both the A and B models have been impacted more severely than the USN variant. Sustained turning performance for the F-35B is being reduced from 5G to 4.5G while the F-35A sinks from 5.3G to 4.6G according to the report.
"It was a judgement call," Schwartz said. "And not an unreasonable one."
In May 2011, Flightglobal reported that the conventional take-off and landing F-35A's combat radius had dropped to 1,080km, or about 11km short of the requirement. The combat radius for the other two F-35 variants had also declined, but remained above their minimum thresholds.
The range was reduced after Pratt & Whitney diverted more bleed air from the F135 powerplant for cooling purposes. The USAF also accepted new estimates that reduced the F-35A's fuel capacity and added the weight and drag of the Lockheed electro-optical targeting system.
Pentagon lowers F-35 performance bar
The US Department of Defense is lowering the performance bar for the Lockheed Martin F-35 Joint Strike Fighter according to a new report by the Pentagon's director of operational test and evaluation (***&E).
The specifications for all three variants pertaining to transonic acceleration and sustained turn rates have been reduced. Worst hit in terms of acceleration is the US Navy's F-35C carrier-based model.
"The program announced an intention to change performance specifications for the F-35C, reducing turn performance from 5.1 to 5.0 sustained g's and increasing the time for acceleration from 0.8 Mach to 1.2 Mach by at least 43 seconds," reads the report prepared by J Michael Gilmore, the Pentagon's ***&E. "These changes were due to the results of air vehicle performance and flying qualities evaluations."
The US Air Force F-35A's time has slipped by eight seconds while the US Marine Corps short take-off vertical landing (STOVL) F-35B's time has slipped by 16 seconds. However, turn rates for both the A and B models have been impacted more severely than the USN variant. Sustained turning performance for the F-35B is being reduced from 5G to 4.5G while the F-35A sinks from 5.3G to 4.6G according to the report.
"It was a judgement call," Schwartz said. "And not an unreasonable one."
In May 2011, Flightglobal reported that the conventional take-off and landing F-35A's combat radius had dropped to 1,080km, or about 11km short of the requirement. The combat radius for the other two F-35 variants had also declined, but remained above their minimum thresholds.
The range was reduced after Pratt & Whitney diverted more bleed air from the F135 powerplant for cooling purposes. The USAF also accepted new estimates that reduced the F-35A's fuel capacity and added the weight and drag of the Lockheed electro-optical targeting system.
Pentagon lowers F-35 performance bar
