| Institut de Stratégie Comparée, Commission Française d'Histoire Militaire, Institut d'Histoire des Conflits Contemporains |
|
||||||||||||||||||
|
|||||||||||||||||||
|
LES
RÉACTEURS F 110
ET F 414 Dennis
K. Williams Vice-President
and General Manager Military
Engines Operations GE
Aircraft Engines
Over the past few years, world events have had a dramatic impact on
the military engine business.The size of the defense market has fallen by as
much as 60 percent from the robust 1980s. At the same time, the customer is
demanding - and rightly so - higher quality and value from our
engines. Engine makers must adapt to this new environment or face
extinction.
With that in mind, I’d like to tell you what we at GE are doing to
reduce cost, improve delivery cycle time, and continually improve the
capabilities of two of our military fighter engines, the F110 and F414. 1.
The F110 Engine Family
The F110 is GE’s high thrust, low cost alternative fighter engine
developed for the US Air Force’s F-16 Fighting Falcon and the US Navy’s
F-14 Tomcat.
The F110 provides up to 30 percent more thrust than the engines
previously used in these front-line fighters. Since entering service in
1986, the F110 engine has amassed more than two million flight hours. It has
seen combat durign Operation Desert Storm and it has been deployed with
front line fighter units around the world. To date, more than two thousand
F110 engines have been produced for F-14 and F-16 fighters.
After an exhaustive three-year technical evaluation of candidate
engines, we at GE were very proud that -
Lowest program risk ; -
Highest engine reliability ; -
Flexibility to accommodate aircraft design variations.
Five flight test engines have been delivered and aircraft ground
testing is now underway. We look forward to the FS-X first flight later this
summer.
We are also working with the US Air Force to qualify the F110-GE-129
engine in the McDonnell Douglas F-15E Strike Eagle - this will provide
enhanced reliability and a lower cost engine alternative for the
F110 powered aircraft are currently stationed around the globe, and
at sea aboard US Navy carriers.
As I mentioned earlier, the F110-GE-129 Increased Performance Engine -
or IPE - is the highest thrust engine in the F110 family. The engine is
rated at 29,000 pounds of thrust (or 129 kilo-
The F110-GE-129 uses the latest proven technologies to achieve high
performance, durability, and safety while keeping costs down by using
« lean » manufacturing techniques. Technology features include a
Full Authority Digital Electronic Control - or FADEC - wich
provides rapid thrust response and stall-free operation and can also be
re-programmed on-wing if needed. A dedicated Engine Monitoring System
continuously tracks engine health, provides part-life tracking data, and
aids in post-flight maintenance diagnosis, if needed. The low-aspect-ratio
three-stage fan has abundant stall margin and bird-strike resistance. The
nine-stage compressor has two inertia-welded rotors for strength, stiffness,
and light weight. Bolted split-cases - used on GE engines for the past
fifty years - simplify fan and compressor maintenance if blade
replacement should ever be needed because of foreign-object damage. Our
latest high-temperature single-crystal blade alloy - René N5 - is
used in the high - and low-pressure turbines (this alloy provides
exceptional high-temperature strength and oxidation resistance for long
life).
We are also working aggressively
to reduce engine costs through the use of innovative manufacturing and
management initiatives. To speed the development of all new or derivatives
engines, GE has formulated the Engine Development Cycle Process - or
EDC. This process guide provides the methodology, structure, and discipline
to track and manage all phases of engine design and development. The EDC
process enhances customer value by :
. Focusing on customer
requirements
. Error-proofing processes
. And reducing cycle time
Other efforts to reduce cost include the wide spread application of
cellular manufacturing, Action Work-Out meetings with suppliers and partners
to increase productivity, electronic data interchange with suppliers, and
pull production - also known as Just-In-Time delivery. Typical benefits
include productivity gains of more than 50 percent and equally impressive
reductions in cycle time and inventory.
Even though the F110 is one of the highest thrust fighter engines in
operation, GE has developed plans for further performance increases, should
our customers need them. We have defined three growth steps that could
increase F110 thrust to more than 40,000 pounds (178 kilo-
Our second growth step would build on Step One to deliver performance
in the 36 to 37 thousand pound thrust range (about 160 kilo-
With these growth plans, the F110 offers the flexibility to meet
evolving customer requirements - whether those needs are increased
performance or improved engine life - for many years to come. I would
now like to share with you the results of the first flight test of a
multi-axis thrust vectoring exhaust nozzle.
As you may have read, GE has developed a multi-axis - pitch and
yaw - thrust-vectoring exhaust nozzle. Thrust vectoring provides an
extra measure of control and agility for fighter aircraft at low airspeeds
and high angles of attack - conditions in which normal control surfaces
are ineffective. Called AVENTM -
for Axisymmetric Vectoring Exhaust Nozzle - the nozzle can change the
direction of the exhaust gas stream to provide additional pitch or yaw
control forces to maneuver the aircraft. The AVENTM nozzle can redirect the exhaust gas stream up to plus or minus 20
degrees in the pitch or yaw axes. The AVENTM
design is also lighter in weight and costs less to produce than a comparable
two-dimensional convergent-divergent pitch only vectoring exhaust nozzle.
Flight tests were conducted by the US Air Force from July 1993 to March 1994
using a specially modified F-16D aircraft and with the vectoring nozzle
installed on a standard F110 engine. Ninety-five flights and 135 hours were
flown during the test program which demonstrated controlled post-stall
aircraft maneuverability.
These were some of the highlights of the flight test program :
. Stabilized flight at a maximum
angle of attack of 83 degrees ;
. Transient flight to a 180
degree angle of attack-flying backwards ;
. Yaw rates as high as 50
degrees per second.
Stall-free, responsive engine operation was crucial for aircraft
control in the post-stall regime. The F110 engine performed flawlessly.
There were no throttle restrictions - pilots frequently made snap
throttle movements from idle to maximum afterburner while flying at zero
airspeed at 30,000 feet. Afterburner lights were even made while flying at
70 degrees angle of attack, zero airspeed and a 50 degree per second yaw
rate. This is truly amazing engine performance ! - but we expected
it. All GE fighter engines have abundant stall margin which allows the pilot
to fly the aircraft - not the engine. Tactical evaluations were
conducted by pilots of the US Air Force’s 422nd Test and Evaluation
Squadron based at Nellis Air Force Base,
The tactical evaluation found that engine thrust vectoring was
superior in close-in air-to-air combat - in both one-versus-one and
one-versus-two engagements. At GE, we are convinced that all-axis engine
thrust vectoring will be the next revolutionary improvement in fighter
aircraft performance. 2.
F414 Afterburning Turbofan
The F414 turbofan is the latest in a long line of high performance
fighter engines designed and developed for the US Navy by GE.
The F414 engine was conceived
during studies begun in 1991 to develop an upgraded F/A-18 fighter with
significant improvements in range and operational capability. Designated the
F/A-18E/F, the Advanced Hornet will be 25 percent larger than the currently
operational F/A-18 Hornet - the US Navy’s premier carrier based
multi-role fighter. The F414 that will power it is a 22,000-pound thrust
class augmented turbofan engine. The F414 engines will provide 35 percent
more thrust than the GE F404 engines used in the original F/A-18. More than
1,000 Advanced Hornets will be produced for the US Navy, with deliveries
beginning in 1999. Initial Operational Capability is anticipated by the year
2000. A major program milestone occurred on May 26th when the first F414
flight test engine was delivered to the Navy in ceremonies at our
Advanced, but well proven technologies allow the F414 to stay the
same length and maximum aft-end diameter of the original F404 while
producing up to 35 percent more thrust ! The F414 fan provides 16
percent more airflow than the F404 fan, with improved bird strike and
foreign object damage resistance features adopted from the F404/RM12 fan.
Performance and reliability have been built into the new advanced power
plant by carefully selecting the latest proven technology from the GE23A,
F412, YF120 and other GE military and commercial engines. In addition to
proven technology, more than five million flight hours of F404 operational
experience have been factored into the F414 design. As a result, durability,
reliability, and performance have been enhanced. The F414 will have a
2000-hour hot section life and a 4000-hour specification life for all other
engine rotating components and structure. Critical rotating disks, shafts
and engine structure have been designed using GE’s robust, damage-tolerant
design practice. This delivers a three-fold improvement in low cycle fatigue
compared to previously used design methods.
As I mentioned earlier, the F414 has a thrust rating of 22,000
pounds, or nearly 98 kilo-
The F414 configuration has been carefully planned for low-risk
development by selectively using proven component technologies. This gives
the F414 an impressive 9-to-1 thrust-to-weight ratio while delivering
improved durability and reliability.
These are some of those features :
. Integrally bladed disks, also called blisks, are used in the second
and third stages of the fan, and the first three stages of the seven-stage
compressor. These blisks provide a 53-pound, or 24-kilogram, weight savings
over more conventional blade and disk dovetail joints. With fewer parts,
blisks also improve overall engine reliability. Using blisk technology, the
F414 has 484 fewer parts in the fan and compressor than the F404.
. A compact, lightweight, annular combustor with 30 thousand
laser-drilled cooling holes significantly lowers combustor wall temperatures
for longer life. Sophisticated manufacturing equipment makes this design
very affordable.
. Highly-loaded single-stage, air-cooled high and low pressure
turbines use GE’s latest single crystal alloys. Three dimensional viscous
flow modeling helped increase low pressure turbine efficiency more than one
percentage point over previous design methods. Thermal barrier coatings also
enhance the durability of both turbines.
. The F414 use GE’s advanced air-cooled radial flameholder and
spraybar system in the augmentor. This will increase flameholder life
substantially when compared to the current F404 design. Durability of this
design has been proven by achieving more than 6000 afterburner cycles,
better than three times life requirements. The radial flameholders, nozzle
secondary flaps and seals are also individually replaceable without having
to disassemble the engine.
. The last feature of the F414 I would like to mention is its
engine-mounted dual-channel full authority digital engine control - or
FADEC. The identical dual-channel FADEC architecture provides the highest
level of reliability and performance in a lightweight system. In addition,
the FADEC provides advanced fault detection logic to identify and adapt to
various system failures.
The F414 engine has undergone extensive development testing as part
of the US Navy’s Engineering and Manufacturing Development program. Design
effort was begun in January 1991. All major engine components were evaluated
in full-scale rig tests prior to running the first test engine. These rig
tests provided valuable time - as much as a year - to optimize the
final component designs. The benefits were realized when the first F414
engine was tested in May 1993 and met all performance goals. The rig tests
also helped to reduce development cycle time - the first engine was
tested two and one-half years before first flight. This provided more time
to find and fix problems during engine development, which will reduce costs
by minimizing design changes after production. To date, more than 4,300
engine test hours - including more than 1,800 hours of endurance
testing - have been completed on seven test engines. The official
endurance test engine has completed more than 1,100 hours, including more
than 300 hours as part of the Durability Proof Test at maximum turbine inlet
temperatures. As I mentioned, the first two flight test engines have been
delivered to the US Navy in preparation for the first flight of the F/A-18E
later this year. By the time we complete the Navy’s Engineering and
Manufacturing Development program in 1998, we will have accumulated more
than 10 thousand test hours on 14 engines. At GE, we’re very proud of the
fact that the F414 program has proceeded on schedule and within the budget
established more than three years ago.
Much of the success of the F414 development program has been due to
its innovative management and design approach. We formed more than 40
Integrated Product Development Teams with representatives from each critical
function and discipline. These teams have been directly involved in the
design, procurement and testing of the F414’s complex engine hardware. US
Navy representatives have also been part of these teams so we could benefit
from the customer’s insight as we progressed. Co-location of teams was
critical to success. Being physically close together greatly enhanced
communication and allowed teams to operate more effectively.
The Integrated Product Development Team approach is paying off. With
F414 engine development 70 percent complete, it is delivering some
impressive results. We have seen design, manufacturing, procurement, and
test cycle time reductions of 20 to 60 percent on many components. Hardware
re-work and scrap costs have fallen dramatically. As an example, the first
test engine required only 25% of the re-work budget compared to previous
programs. Also noteworthy, about 80% of all hardware for the first test
engine came from production sources. The number of design changes is about
two-thirds less than the historical average. All major program milestones
are on or ahead of schedule. The best example of benefits of Integrated
Product Development was demonstrated by the Afterburner and Exhaust Nozzle
Team. They designed, developed, and fabricated the first afterburner and
exhaust nozzle assembly for full-scale engine testing in just 14 months !
This saved the F414 program 17 months compared to previous military engine
programs.
Recognizing that the F/A-18E/F will assume new roles and missions
over its lifetime, as well as face an uncertain and ever changing threat
environment, we designed the F414 with thrust growth potential to meet these
anticipated needs. Already envisioned for the F414’s first growth step is
a 10 percent thrust increase that could be available by 2005. Increased
performance would be achieved with an improved core having an all blisk
compressor and higher temperature turbine alloys to withstand a modest
temperature increase. The second growth step would provide 15 percent more
thrust than today’s F414 - about 25,000 pounds of thrust (or roughly
111 kilo-
We at GE Aircraft Engines are proud - and we think justifiably
so - to be developing the F414 for the US Navy’s next generation
multi-role fighter. We believe that this engine and the continuously
improving F110 will both play important roles in the military sector as we
enter the twenty-first century. By applying GE’s innovative manufacturing
and management techniques to reduce cost, compress delivery cycle time, and
continuously improve the capabilities of all our military products, we plan
to achieve new levels of value and reliability to meet or exceed customer
requirements now and in the future. Thank you for your attention
|
||||||||||||||||||
|
|
Copyright www.stratisc.org - 2005 - Conception - Bertrand Degoy, Alain De Neve, Joseph Henrotin |
||||||||||||||||||