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发帖数: 38600 | 1 Pentagon’s big budget F-35 fighter ‘can’t turn, can’t climb, can’t run’
http://blogs.reuters.com/great-debate/2014/07/14/pentagons-big-
The U.S. military has grounded all its new F-35 Joint Strike Fighters
following an incident on June 23, when one of the high-tech warplanes caught
fire on the runway of a Florida air base. The no-fly order — which affects
at least 50 F-35s at training and test bases in Florida, Arizona,
California and Maryland — began on the evening of July 3 and continued
through July 11.
All those F-35s sitting idle could be a preview of a future in which
potentially thousands of the Pentagon’s warplanes can’t reliably fly.
To be fair, the Pentagon routinely grounds warplanes on a temporary basis
following accidents and malfunctions to buy investigators time to identify
problems and to give engineers time to fix them.
But there’s real reason to worry. The June incident might reflect serious
design flaws that could render the F-35 unsuitable for combat.
For starters, the Lockheed Martin-built F-35 — which can avoid sensor
detection thanks to its special shape and coating — simply doesn’t work
very well. The Pentagon has had to temporarily ground F-35s no fewer than 13
times since 2007, mostly due to problems with the plane’s Pratt & Whitney-
made F135 engine, in particular, with the engines’ turbine blades. The
stand-downs lasted at most a few weeks.
“The repeated problems with the same part of the engine may be indications
of a serious design and structural problem with the F135 engine,” said
Johan Boeder, a Dutch aerospace expert and editor of the online publication
JSF News.
Pratt & Whitney has already totally redesigned the F135 in an attempt to end
its history of frequent failures. But there’s only so much engineers can
do. In a controversial move during the early stages of the F-35′s
development, the Pentagon decided to fit the plane with one engine instead
of two. Sticking with one motor can help keep down the price of a new plane.
But in the F-35′s case, the decision proved self-defeating.
That’s because the F-35 is complex — the result of the Air Force, Marines
and Navy all adding features to the basic design. In airplane design, such
complexity equals weight. The F-35 is extraordinarily heavy for a single-
engine plane, weighing as much as 35 tons with a full load of fuel.
By comparison, the older F-15 fighter weighs 40 tons. But it has two engines
. To remain reasonably fast and maneuverable, the F-35′s sole F135 engine
must generate no less than 20 tons of thrust — making it history’s most
powerful fighter motor.
All that thrust results in extreme levels of stress on engine components. It
’s no surprise, then, that the F-35 frequently suffers engine malfunctions.
Even with that 20 tons of thrust, the new radar-dodging plane is still
sluggish. The F-35 “is a dog … overweight and underpowered,” according to
Winslow Wheeler, director of the Straus Military Reform Project at the
Project on Government Oversight in Washington.
In 2008, two analysts at the RAND Corporation, a California think-tank that
works closely with the military, programmed a computer simulation to test
out the F-35′s fighting ability in a hypothetical air war with China. The
results were startling.
“The F-35 is double-inferior,” John Stillion and Harold Scott Perdue
concluded in their written summary of the war game, later leaked to the
press. The new plane “can’t turn, can’t climb, can’t run,” they warned.
Yet the F-35 is on track to become by far the military’s most numerous
warplane. It was designed to replace almost all current fighters in the Air
Force and Marine Corps and complement the Navy’s existing F/A-18 jets. The
Pentagon plans to acquire roughly 2,400 of the radar-evading F-35s in coming
decades, at a cost of more than $400 billion.
Like it or not, the stealthy F-35 is the future of U.S. air power. There are
few alternatives. Lockheed Martin’s engineers have done millions of man-
hours of work on the design since development began in the 1990s. Starting
work on a new plane now would force the Defense Department to wait a decade
or more, during which other countries might pull ahead in jet design. Russia
, China and Japan are all working on new stealth fighter models.
The Pentagon sounds guardedly optimistic about the current F-35 grounding.
“Additional inspections of F-35 engines have been ordered,” Rear Admiral
John Kirby, a military spokeman said, “and return to flight will be
determined based on inspection results and analysis of engineering data.”
Minor fixes might get America’s future warplane flying again soon — for a
while. But fundamental design flaws could vex the F-35 for decades to come,
forcing the Pentagon to suspend flying far too often for the majority of its
fighter fleet, potentially jeopardizing U.S. national security. |
