|
The F-35 Propulsion Systems are the most powerful fighter/attack
turbofans in the world. There are two manufacturers with propulsion
systems currently being tested. The propulsion systems are
interchangeable and both will power the F-35. There are two
major engine variants for the F-35. One engine will power
the CTOL and CV versions of the aircraft, while the other
will power the STOVL version. The F135 engine is made by Pratt
& Whitney, the F136 by a team, known as the Fighter Engine
Team comprised of General Electric and Rolls-Royce. Both the
F135 and the F136 STOVL engines will utilize common exhaust
and Lift System systems.
F135
The Pratt & Whitney F135 family of advanced propulsion
systems utilize cutting edge technology to provide the F-35
with higher performance than conventional fighter aircraft.
The engine consists of a 3-stage fan, a 6-stage compressor,
an annular combustor, a single stage high-pressure turbine,
and a 2 stage low-pressure turbine.
The F135 is currently in the SDD phase.
The F135 is using the lessons learned from the F119 engine
core and the JSF119 during the CDA stage to reduce risk in
SDD. During SDD the F135 test engines will undergo a range
of ground and flight tests to simulate various mission profiles.
In these tests the system demonstration engines will be run
for hours throughout various flight envelopes to ensure they
meet performance requirements. One of the vital milestone
tests occured at the end of 2003 with the first F135 engine
to test.
The first CTOL F135 engine test occurred
on 11 October 2003. The First STOVL F135 engine test occurred
on 14 April 2004. To date over 2,000 hours have been accumulated
on the F135 test engines.
F136
The GE Rolls-Royce Fighter Engine Team (FET) F136 engine is
currently in its Phase III, Pre-SDD portion of the program.
The objective of the F136 Pre-SDD phase is to match engine
design as closely as possible to that of the final aircraft
configuration, thereby minimizing changes and keeping pace
with evolving aircraft demands prior to entering SDD. The
F136 engine consists of a 3-stage fan, 5-stage compressor,
a 3-stage low-pressure turbine section, single stage high-pressure
turbine, and a radial augmentor.
The F136 team will transition into the SDD
phase of their program later in 2005. The F135 and F136 teams
are working closely to develop common propulsion system components.
This unique arrangement of "COOPETITION" was spawned
by the Joint Strike Fighter Program's emphasis on affordability.
The first F136 CTOL engine was successfully
tested for the first time on 22 July 2004. Testing on the
first F136 STOVL propulsion system began on 10 February 2005.
The F136 engines undergo testing at GE facilities in Peebles
and Evendale, Ohio. To date, the F136 team has accumulated
over 100+ hours of engine tests.
Rolls-Royce Lift System
While Rolls-Royce is a member of the Fighter Engine Team with
GE on the F136, they are also subcontracted to Pratt &
Whitney on the F135 to provide the Lift System for the F-35.
The Lift System is comprised of the Lift Fan, Clutch, Drive
Shaft, Roll Posts and the Three Bearing Swivel Module (3BSM).
Shaft Driven Lift Fan (SDLF)
Lockheed Martin developed the idea for a Short Take-Off Vertical
Landing (STOVL) lift system that uses a vertically oriented
Shaft Driven Lift Fan (SDLF). A two-stage low-pressure turbine
on the engine provides the horsepower necessary to power the
Rolls-Royce designed Lift Fan. The Lift Fan generates a column
of cool air that provides nearly 20,000 pounds of lifting
power using variable inlet guide vanes to modulate the airflow,
along with an equivalent amount of thrust from the downward
vectored rear exhaust to lift the aircraft. The Lift Fan utilizes
a clutch that engages the shaft drive system for STOVL operations.
Because the lift fan extracts power from the engine, exhaust
temperatures are reduced by about 200 degrees compared to
traditional STOVL systems.
The SDLF concept was successfully demonstrated
through a Large Scale Powered Model (LSPM) in 1995-96 and
during the flight-testing of the X-35B during the summer of
2001. The Lift Fan, a patented Lockheed Martin concept, was
developed and produced by Rolls-Royce Corp. in Indianapolis,
Indiana and in Bristol, England.
|
|
|
|
|
|
|
|
|
| |
