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 Japan selected the F110-GE-129 Increased Performance Engine - or IPE - to power their single engine FS-X fighter. Three factors that had the greatest influence in the selection of the F110 IPE for the FS-X were :

- 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 United States and other countries that fly this aircraft. Since this engine was the first Increased Performance Engine to fly in the F 15E, and successfully completed development flight testing in 1989, a modest qualification program of fewer than 25 test flights will be required. An Integrated Product Team with members from the US Air Force, McDonnell Douglas, and GE has been formed to manage this effort. This team effort will help the program meet aggressive schedule objectives and keep overall costs to a minimum. Testing begins in November of this year at Edwards Air Force Base in California . Following the review and documentation of flight test results, we expect the F110 IPE to receive official US Air Force qualification for the F-15E in the third quarter of 1996.

 

            F110 powered aircraft are currently stationed around the globe, and at sea aboard US Navy carriers. US Air Force F-16s are stationed at 29 bases throughout the United States , Europe , Japan , and Korea . Since being offered in 1984, the F110 has been selected to power 73% of all F-16C/D Block 30, 40, and 50 series aircraft. Besides the US Air Force and Navy, five other nations rely on F110 - powered F-16s : Bahrain, Egypt, Greece, Israel and Turkey (Turkey and Greece have also selected the F110-GE-129 in follow-on F-16 purchases - In addition to assembly at GE’s facilities, F110 engines are currently being assembled by Tusas Engine Industries in Turkey). Each month, more than 30,000 hours are flown by F110 - powered fighters.

 

            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- Newtons ) in maximum afterburner. Developed and fully qualified, the - 129 has been in service with the US Air Force since 1992. More than 240 engines have been delivered so far. Current unfilled orders will keep us producing this engine at least through 1998.            Licensed production by IHI of Japan for the FS-X is expected to keep the F110-GE-129 in production through 2007. Through May of this year, the F110-GE-129 had accumulated more than 85,000 flight hours in the single-engine F-16C/D Block-50 fighter. Engine reliability has been exceptional. US Air Force F-16s in Europe have been flying peace-keeping missions averaging 40 to 50 hours each month with better than 99 percent mission completion rate. This is more than double the normal peacetime rate historically flown by F-16s. At one deployed location, F-16s are each flying four sorties per day, week after week - a total of 60 to 80 hours per month. US Air Force F-16s are today flying alongside French Mirages under the United Nations flag for peace-keeping missions over Bosnia .

 

            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- Newtons ). The first step would deliver a 15 to 20 percent thrust increase to about 33,000 to 35,000 pounds (156 kilo- Newtons ). Engine ratings will depend on customer requirements. As an alternative, this step could provide a 40 percent increase in engine parts life at current thrust levels. Development work is already underway, and the engine will be qualified in 1998. Hardware modifications would include the high efficiency three stage integrally bladed disk - or blisk - fan adapted from the F118 engine on the B-2 bomber. We would also apply an advanced augmentor design using air-cooled radial flameholder and spraybar assemblies adopted from the YF120 and F414 engines. This low cost derivative design will greatly extend flameholder life. Survivability features could be incorporated to reduce engine thermal and radar signatures.

 

            Our second growth step would build on Step One to deliver performance in the 36 to 37 thousand pound thrust range (about 160 kilo- Newtons ). To accomplish this, we would employ the latest CFM56 high-efficiency core. Dual use of this advanced engine core will lead to lower development costs and improved reliability for both engine programs. We would also introduce a long-life combustor with a laser-drilled multi-hole cooling pattern ; an air-cooled low pressure turbine, and a dual channel FADEC. While increasing performance and reliability, we also expect to cut engine acquisition cost compared with today’s F110 engine. This will be done by using Quality Function Deployment and Design to Cost methods to select those technologies that satisfy critical customer requirements at the lowest life cycle cost. In the third growth step, we could provide 40 thousand pounds of thrust by simply scaling up the blisk fan. However, the increased fan diameter and higher airflow would demand a larger inlet and structural modifications to existing F110 applications. Variable cycle engine technology, as first employed on our YF120 for the Advanced Tactical Fighter program, may also be used on the F110. A variable cycle engine can provide thrust tailoring throughout the flight envelope and delivers greater flexibility than a fixed cycle turbofan of the same size.

 

            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, Nevada . F-16 and F/A-18 adversaries were flown against the AVENTM-equipped F-16D.   Thrust vectoring demonstrated new offensive and defensive capabilities that delivered a decisive advantage during these tests.

 

            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 Lynn , Massachusetts plant. After engine installation and ground testing, the first flight of the F/A-18E/F will take place in December of this year at the McDonnell Douglas facility in St. Louis , Missouri .

 

            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- Newtons . This equates to a 35 percent thrust increase over the original F404 engine. More importantly, the F414 provides significant thrust increases in areas of the flight envelope critical to a multi-mission aircraft like the F/A-18E/F. It has 30 to 40 percent more thrust in the heart of the flight envelope to give the F/A-18E/F the advantage during close-in aerial combat , 25 to 30 percent more thrust supersonically for high altitude air combat intercept missions  and over 40 percent more thrust for low-altitude air-to-ground missions where high speeds to and from the target area greatly enhance aircraft survivability.

 

            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- Newtons ). This engine would use the improved Step A core with a larger fan and low-pressure turbine. It would still fit within the existing F/A-18E/F engine installation, however. The final growth step - Step C - would produce an engine with 30 percent more thrust than today’s F414 - just under 29,000 pounds, or about 128 kilo- Newtons . This thrust level is nearly equal to today’s F110 Increased Performance Engine. To reach this impressive thrust level will demand further airflow growth from the fan, a modest temperature increase, a new two-stage low pressure turbine and a new afterburner.

 

            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