Marine Corps' Joint Strike Fighter Expected To Make First Flight This
Month Defense Daily June 2, 2008
The Marine Corps' Joint Strike Fighter (JSF) variant should fly for
the first time in conventional mode this month and make its maiden
short-take-off-and-vertical-landing (STOVL) flight around the first of
the year, according to airframe builder Lockheed Martin [LMT].
The F-35B STOVL variant of the stealth fighter is expected to embark
on its first flight "probably within the next week or so," Lockheed
Martin spokesman John Smith said last Friday, though a specific date
had not been set at the time.
The F-35B's shaft-driven lift fan propulsion system--that will enable
the fighter to make the short takeoffs and vertical landings for which
it is intended--operated for the first time in the aircraft during
ground testing on May 25, the company said last Friday.
A test pilot performed two conversions from conventional to STOVL mode
when the aircraft was anchored to a hover pit at Lockheed Martin's
STOVL test facility in Fort Worth, Tex., according to a Lockheed
Martin press release.
"The F-35B's STOVL propulsion system operated exactly as expected,
providing the power output that our models forecast and transitioning
very smoothly from conventional to STOVL-mode and back," Bobby
Williams, Lockheed Martin vice president and F-35 deputy program
manager, said in the release.
Before the first flight in the coming weeks, the F-35B is conducting a
final series of ground tests.
The aircraft is flying in conventional mode during the initial test
flights "to evaluate overall flying qualities and airworthiness," the
company says.
The Pentagon's purchase of a half dozen F-35Bs hinges in part on the
upcoming conventional-mode flight. When Pentagon acquisition executive
John Young approved the purchase of additional JSFs in April, as part
of a Low Rate Initial Production II stage, he said six STOVL variants
could not be bought until the F-35Bs have a successful first flight
(Defense Daily, April 15).
The program has had some hiccups. During proof testing in February, a
third-stage turbine blade of the F135 engine vibrated while at very
high frequencies at a stress level that can cause it to crack, and
cracks and holes were discovered, according to F135 engine developer
Pratt & Whitney [UTX] (Defense Daily, March 20). A similar fatigue
issue had been discovered last August, during an early phase of the
qualification program.
"Our aim is to retire technical risk well before we deliver F-35s to
the fleet," Williams said.
The JSF STOVL variant is expected to reach initial operating
capability in 2012.
Current plans call for the F-35B to be moved the Naval Air Station in
Patuxent River, Md., early next year, though Smith said it has not
been decided if the initial STOVL flights planned for December or
January will be in Fort Worth or in Patuxent River.
The JSF effort--which is developing variants for the Air Force, Marine
Corps and Navy--is the Air Force's largest acquisition program.
Lockheed Martin is developing the F-35 with partners Northrop Grumman
[NOC] and BAE Systems. In addition to Pratt & Whitney, a team made up
of General Electric [GE] and Rolls-Royce is developing a second
engine--the F136--for the JSF, though it is not as far along in
development as Pratt & Whitney's F135.