2000 Is (Nearly) Now

Feb. 1, 1987

The year is 2000; the place is Ed­wards AFB, Calif. At the end of the three-mile-long runway, USAF’s newest fighter, the YF-3 1, perches on its landing gear, its idling engine releasing shimmering heat waves. Cleared for takeoff, the YF-3 l’s pilot advances the throttle to begin the aircraft’s first test flight. The engine’s rumble builds to a roar. He releases the brakes, and the sleek fighter begins to roll.

Old-timers in the crowd of ob­servers are astonished. Less than twenty-five feet from brake release, the YF-31’s nose rises. The main gear leaves the ground after another fifty feet. By 200 feet, the 50,000-pound YF-31 is fifty feet above the runway, nose pitching upward. Ob­servers see the nearly transparent white plume from the engine ex­haust. As the nose reaches the ver­tical, the aircraft continues to accel­erate heavenward with a roar.

By the midpoint of the runway, the YF-31 is a vanishing speck shooting high into the clear desert sky. It quickly disappears from sight. There is silence for a moment, and then a sonic boom reaches the crowd. The YF-31 has exceeded Mach 1 in vertical flight its first time in the air.

In 1987, that scene is speculative. But it will surely be realized by the year 2000, if not well before. Such astonishing performance will be possible because the advanced pro­pulsion systems to make it happen are already in development by the Air Force and industry.

Propulsion advances take a long time to move from laboratory into reliable flight, ten to fifteen years. If US military aircraft of 2000 and be­yond are to remain ahead of the competition, the groundwork must already be under way in earnest.

It is. Experts at Air Force Sys­tems Command’s Aeronautical Sys­tems Division (ASD) and their counterparts in industry can al­ready define the major trends in mil­itary aircraft propulsion between now and the year 2000.

First, ASD’s Propulsion deputate says, more different propulsion de­velopment work is going on than ever before. Developments are cas­cading forward on a wide front, from the laboratory and the shop floor to enhancement work on op­erational aircraft. Advances all along that front are being intro­duced into operational use faster than before. At the same time, the laboratories are pushing the fron­tiers of technology to ensure contin­uous progress. And in the factories, manufacturing innovations are mak­ing the process more rational, more efficient, and more affordable.

USAF goals for aircraft propul­sion are clearly established. Im­proved performance is one major and vital goal. Gen. Lawrence A. Skantze, Commander of AFSC, says, “Historically, the Air Force has emphasized performance—fly faster, turn quicker. . .

Formerly, performance was the goal. It overrode other considera­tions. That is changed. General Skantze says that other goals are now being paid serious attention. Among them are the “-ilities”: qual­ity, which includes increased reli­ability, plus maintainability, dura­bility, sustainability, and affordabil­ity. Still other goals include reduc­ing costs and ensuring competition among suppliers at every level.

Both the Air Force and industry are following strategies that permit breakthroughs to be applied to ex­isting systems in an evolutionary process. At the same time, they are pushing the frontiers of technology through basic research.

Building on the Present

The conceptual system approach is a break from past practices in pro­pulsion development. It builds new capabilities more quickly by im­proving present engines and adapt­ing engine configurations to more than one mission.

A major effort in that direction is a program called Increased Perfor­mance Engine (IPE). The IPE program improves two existing en­gines, the Pratt & Whitney 17100­PW-220 and the General Electric F110-GE-100.

The Pratt & Whitney -220 evolved from the original F 10 that powered the first F- 15 and F- 16 fighters. The GE Fl 10 engine came into the pic­ture when the Air Force decided to call for a second source to Pratt & Whitney. USAF conducted the Al­ternate Fighter Engine (AFE) com­petition, and now both the 17100­PW-220 and F110-GE-100 are qualified. An annual competition determines what percentage of the next year’s purchase of these en­gines goes to each of the two sup­pliers.

Both alternate fighter engines are now flying in operational aircraft. In July 1986, the Air Force accepted its first F-16 powered by the F110- GE-100, and in October 1986, the first F-15 fighter equipped with Pratt & Whitney’s F100-PW-200 was delivered.

The Alternate Fighter Engine competition achieved two major goals: durability parity and cost competition. The meaning of cost competition is clear. “Durability parity” means that both of the alter­nate fighter engines are equally du­rable. They can operate for 4,000 tactical cycles, or about 2,000 hours, before teardown for major inspection. For a tactical fighter, that means the engine remains in the aircraft for up to eight to ten years before it must be removed.

Major goals of the Improved Per­formance Engine programs are to retain (and improve) the durability (at least 4,000 tactical cycles) of the alternate fighter engine, to reduce cost of ownership, and to achieve thrust parity. Present thrust is about 27,000 pounds for the Fl 10-GE-100 and about 24,000 pounds for the F100-PW-220. Both will be im­proved to deliver the same thrust: 29,000 pounds. In the process, over­all performance in operation will be improved.

At the same time, the Air Force is developing increased competition. The prime contractors, GE and Pratt & Whitney, are dual-sourcing critical components of both en­gines, such as fuel pumps and digital electronic controls. For example, GE formerly bought F110 fuel pumps only from Sundstrand. It has now brought in TRW as a second source for fuel pumps for the Fl 10­GE-129 engine.

First flights of both IPE engines are not far off. Pratt & Whitney’s engine, designated F100-PW-229, is scheduled to fly in an F-15 in No­vember 1987. Soon after, in January 1988, GE’s improved engine, tagged Fl l0-GE-129, will take to the air in an F-16.

The result for aircrews will be higher performance of the F-15 and F-16 with lower maintenance re­quirements and costs. The im­proved performance engines can be installed in new aircraft or selec­tively retrofitted into existing ones.

STOL Maneuvering Demonstrator

In March 1988, two months after the F-16 flies with the GE -129, an­other derivative aircraft will take off on its maiden flight. The STOL Ma­neuvering Technology Demonstra­tor, or SMTD (STOL stands for Short Takeoff and Landing), is a

McDonnell Douglas F-15 that looks much like other USAF Eagles. But it is packed with modifications that give it “gee-whiz” performance.

The objectives of the SMTD pro­gram are to investigate, develop, and validate four promising technol­ogy areas that will give fighters a true STOL capability. They are:

• Advanced pilot/vehicle inter­face;

• Rough- and soft-field STOL landing gear;

• Two-dimensional (2-D) vector­ing and reversing nozzle; and

• Integrated flight and propulsion control.

Why is STOL capability impor­tant for F-15s and future fighters? Because in future conflicts, the lux­ury of 10,000-foot runways will probably be only a memory. They will be cratered and cut, with only short stretches usable. Some fight­ers will probably have to operate from highways or rough and short fields as well.

Two of the four technologies—the 2-D vectoring and reversing nozzles and the integration of flight and pro­pulsion controls—are pertinent to the SMTD. Together, they create extraordinary additional perfor­mance using the Fi00-PW-220 en­gines.

The label “2-D nozzles” on the SMTD means that the nozzles are rectangular (two dimensions, length and width) instead of circular. Ex­haust from circular nozzles creates drag. If drag is reduced, perfor­mance is improved. More of the en­gine thrust is used to push the air­plane along.

The nozzles are not only 2-D: they are also vectoring and revers­ing. Thrust need not flow straight back from the engine centerline. It can be directed up or down, or it can be reversed.

By integrating the flight controls with the propulsion controls, the SMTD pilot is able to use propulsive force as a flight control. A central computer uses software to bring to­gether the flight controls, engine controls, and nozzle controls to achieve increased performance.

For example, for takeoff, the pilot advances the throttle and begins rolling. When he exerts back pres­sure on the stick, the nozzles move to vector the thrust, giving addition­al lift and pushing the F-is SMTD into the air earlier. In flight, when the F-IS pilot needs to gain advan­tage over an enemy, vectoring en­hances maneuverability. Roll rates are improved by nearly twenty per­cent, for instance.

Even more dramatic are improve­ments in agility. The F-15 SMTD can accelerate and decelerate, pitch, and point better than most other aircraft. When it is time to land, the vectoring, integrated pro­pulsion, and precision flight path controls permit the pilot to plant the aircraft on the ground at slower speeds, in shorter distances, and in worse conditions than at present.

For example, it will be able to oper­ate from a wet runway only fifty feet by 1,500 feet, in a crosswind of from twenty-six to thirty knots, and with a 200-foot ceiling and a half mile of visibility—all without the need for active ground landing aids at the runway.

Another important SMTD feature is survivability. The aircraft will still be controllable and able to land in 2,000 feet even if a movable surface is shot off one side, a nozzle will not work, or one engine is lost.

In the past, the jumps in capabili­ty that the SMTD will deliver would have required designing a new air-frame-engine combination. This program builds technology ad­vances on existing systems. The re­sults lead to derivative aircraft or earlier application of the technology to new fighters, such as the Ad­vanced Tactical Fighter (ATF).

Propelling the ATF

Lt. Gen. William E. Thurman, Commander of Aeronautical Sys­tems Division, which directs the Advanced Tactical Fighter program, declares that “the ATF will be the Air Force’s air-superiority fighter for the year 2000 and beyond.” Two companies, Lockheed and Nor­throp, are the prime contractors. Each leads a team in a fifty-month demonstration and validation phase of ATF development. Contracts worth $691 million to each team were awarded at the end of October 1986.

Propulsion for the ATF will be from either the competing Pratt & Whitney or General Electric en­gines. Contracts for those efforts were awarded three years earlier, in September 1983. The prototype ATF engines have benefited—and will benefit—from lessons learned in earlier engines and from technol­ogy developments now under way.

Both airframe teams are develop­ing prototype aircraft for a flyoff evaluation. Lockheed’s is the YF-22A; Northrop’s is the YF-23A. Each team will build two proto­types—one to use the GE and the other the P&W engine. Under pres­ent plans, competition will be an option that can be carried through­out the program, even after full-scale development is started.

Requirements for the ATF are tough—and mostly classified. How­ever, the propulsive thrust can be estimated. The Air Force wants a thrust-to-weight ratio (engine thrust/aircraft weight) of 1.2 or bet­ter. (The F-IS Eagle’s T/W is about 1.05 with augmentation, or after-burning.) Assuming the aircraft will weigh about 50,000 pounds, then thrust of 60,000 pounds or more is needed. Consider other general re­quirements:

• Supercruise. The ATF will cruise long distances at supersonic speeds. At present, most super­sonic aircraft do so for only short times and require augmentation (af­terburning) to do so. The ATF en­gine must provide sustained super­sonic cruise of about Mach 1.8 at 40,000 feet without augmentation. That means a turbojet or low-bypass turbofan with high turbine inlet tem­peratures and 2-D nozzles.

• Range. USAF wants substan­tially greater range from the ATF and wants to get it without using external fuel tanks. Low specific fuel consumption (sfc) is required from the engine, much more effi­cient than at present. (Specific fuel consumption is a measure of effi­ciency, expressed in pounds of fuel burned per pound of weight per hour. For instance, the thirty-year-old GE J85 engine in the T-38 Talon trainer has an sfc of 1.0. The lower the sfc, the better.)

• Maneuverability. The ATF has to win, both at long-range and close-in air combat. For that, it needs a high-thrust engine that weighs much less than existing engines and a sys­tem that integrates propulsion and flight controls for fighting agility.

• Short-field capability. Again, high thrust-to-weight ratio, thrust reversing and vectoring, and inte­grated propulsion and flight con­trols are needed.

• Survivability. The ATF must be able to sustain damage without los­ing the aircraft.

• Supportability. ATF operations from remote fields with minimum equipment must be ensured. Less support equipment also means fewer transport aircraft sorties to reach an austere forward base.

• Affordability. Life-cycle cost must be minimized. This can be achieved by slashing the number of parts, by making it easy to get at the engine, and by minimizing the number of tools needed to perform maintenance.

The ATF engine will have built-in engine monitoring systems to en­sure that the “-ilities” are achieved. They will be integrated with avi­onics, flight controls, and other sys­tem monitors. The information from all will be integrated into a di­agnostic system. In the words of Col. Albert J. Piccirillo, outgoing ATF program manager, “We want to know early what’s wrong and fix it right away. It is faster, cheaper, and creates more sorties.” Colonel Pic­cirillo will be replaced by Col. James Fain.

Both ATF engines are undergoing ground tests now. Their Air Force designations are YF1 19 for the Pratt & Whitney and YF120 for the GE engine. Three flightworthy engines will be delivered to the Northrop and Lockheed ATF teams for in­stallation in their prototype aircraft, now expected to fly in late 1989. By late 1990, source selection will be made, and the full-scale develop­ment process will begin. First flight of the winning ATF will take place at the end of 1992, and the first squad­ron will be in operation by early 1996.

To meet the accelerated ATF time schedule and to deliver reliable air­craft that will meet the require­ments, the YF1 19 and YF120 en­gines must exploit every possible technology available today or rea­sonably expected in the near future. It will be done, say the companies (GE and P&W) and the customers (the Air Force developers).

Derivative Strategies

The successful ATF propulsion system will be but one of several achievements in the field between now and the year 2000. Others will evolve from continued attention to two basic approaches. First is creat­ing derivatives of present models. Second is transforming break­throughs in the laboratory to produc­ible components of new engines.

The first approach is epitomized in the Engine Model Derivative Pro­gram (EMDP). It provides a frame­work for blending advances into ex­isting systems and for future growth. That includes finding exist­ing commercial applications that meet USAF requirements. EMDP, begun in 1978, demonstrates what is feasible. After demonstration, full-scale development can take place. The program shares costs with in­dustry. Using fixed-price develop­ment contracts, EMDP and a con­tractor both put up money for a demonstration.

Past projects that have shown re-suits include the GE F101 derivative fighter engine that became the 171 10. It reestablished competition for engines for the Air Force F-15 and F-16 and the Navy F-14 Tom­cat. USAF cost was $83 million, but the competition is expected to save the service upward of $1 billion.

The GE and P&W Improved Per­formance Engines mentioned ear­lier evolved under the EMDP tent. Competition was again a major ob­jective, along with higher thrust and incorporation of such developments as digital electronic engine controls.

Another EMDP project just fin­ishing in January 1987 involves the Williams International FJ44 engine. The Williams F144 was a commer­cial development program with ap­plicability in general aviation. The Air Force rationale in this case is to demonstrate that the FJ44 can be an alternative to the Garrett F109 en­gine in the T-46 trainer aircraft, if that program proceeds. Also, USAF has a choice of engines for new planes, such as lightweight at­tack or forward air control aircraft.

An example of demonstrating commercial adaptation for USAF use involves the reengining of Stra­tegic Air Command’s KC-135 tank­ers. Up to 390 aircraft in the KC-135A fleet are having their tur­bojet engines replaced with tur­bofans. The engine of choice for this batch has until now been the CFM56-2 turbofan from CFM Inter­national, a product of GE and SNECMA cooperation. In USAF use, it is designated the F108.

Now, under EMDP, a commercial engine is being considered for the KC- 135 reengining. The rationale is to put competitive pressure on CFM International while minimiz­ing Air Force upfront costs. The al­ternate engine is called the V2500. It is a 25,000-pound-thrust engine un­der development by the five-nation consortium called International Aero Engines in Hartford, Conn. Partners in IAE are Pratt & Whit­ney, Rolls-Royce, Japanese Aero Engine Corp., MTU (West Ger­many), and Fiat (Italy).

ASD analysts say that the V2500 can be a valid competitor. If the en­gine develops as planned and the analyses hold, they estimate the V2500 will use up to seventeen per­cent less fuel than the F108. Also, they estimate that a KC-135R with the V2500 engine will be able to car­ry about seventeen percent more fuel on a refueling mission to tank up other aircraft.

The advantages to the Air Force include leverage for improved war­ranties, expanded dual-sourcing, and contractor responsiveness.

Other possible payoffs from the EMDP in the early to mid-1990s are in propulsion for the B-I B bomber and the A-7 attack aircraft. For the B-1B, 2-D nozzles for its GE F101 engines could demonstrate a capa­bility for additional thrust. On the A-7, adding augmentation (after-burning) to the Allison T41 engine or adapting the GE F 110 or P&W 17100 would give the Corsair II a supersonic capability. It would be an “A-7 Plus.”

In the Laboratories

Research and exploratory devel­opment for high-performance pro­pulsion advances by the year 2000 is now being conducted in laboratories of the Air Force and industry. More than twenty-five projects involving six engine companies are under the broad title of HPTET. HPTET stands for the High-Performance Turbine Engine Technology initia­tive.

Five years ago, Aeronautical Sys­tems Division did a study to deter­mine what could be done to get bet­ter turbine engine propulsion in the future. The study concluded that if materials could be improved—that is, be lighter and stronger while oper­ating at higher temperatures—then major advances could be made. The study recommended a focused effort to develop the technologies to make the necessary leaps.

Gen. Lawrence A. Skantze, Commander of Air Force Systems Command, endorsed the conclu­sions and recommendations. He got industry involved in the exercise. In the summer of 1985, Air Force and engine industry groups worked to­gether to establish goals and identi­fy the critical problems that must be overcome. The two main goals are to double engine thrust-to-weight ratio (TIW) and cut cruise fuel con­sumption in half by the year 2000. That wrote the marks on the wall, the targets to strive toward.

Engine T/W is thrust in pounds over weight in pounds. Today, for the latest F100-PW-220 engine, it is 24,000 pounds of thrust over 3,200 pounds of weight, or 7.5:1. The en­gine for the Advanced Tactical Fighter is expected to have a T/W of 10:1 in the mid-1990s, a major step forward. Rolls-Royce engine scien­tists agree that 10:1 will be achieved in the engine for the European Fighter Aircraft of the mid-1990s, and they see 12:1 as realistic by the year 2000. Under HPTET, the Air Force and laboratories of the engine manufacturers are striving to reach a T/W of between 15:1 to 20:l by the year 2000. Even if they achieve only 12:1, that is more than fifty percent better than at present.

HPTET is a joint project of ASD’s Aero Propulsion Laboratory and its Materials Laboratory. Engine com­panies participating in HPTET are Allison, Garrett, General Electric, Pratt & Whitney, Teledyne, and Wil­liams International. Each company has described its own path toward overcoming critical problems and reaching the major goals. But all are working under the plan developed together with AFSC.

The focus is not on a single area, but across the board. For example, advances in computer capabilities mean that corresponding advances can be made in aerothermodynam­ics—the study of the effects of heat on gasses, as in air flow through gas turbines. That means efficiencies achieved from the start, in the basic design. Other elements of HPTET concentrate on breakthroughs in materials. The search is not limited to engine companies. Others, such as Lockheed and Alcoa, are pursu­ing advanced materials.

Ability to operate at higher tem­peratures is a major element in in­creasing engine efficiency. In sim­plified terms, at higher tempera­tures, more thrust is achieved from each pound of fuel. And efficiency is also improved by the use of lighter materials. If engine thrust remains constant but the engine weighs less, then thrust-to-weight ratio is im­proved.

The Search Is On

So the search is on to develop materials both lighter and more tol­erant of higher temperatures. An­other important reason for the quest for new materials is to reduce US dependence on foreign suppliers for basic metals used in turbine en­gines. Something like 800 pounds of cobalt imported from Africa are used in an F 100 fighter engine. If the cobalt can be replaced by other ma­terials, then the US is not tied to a string that can be jerked by an un­friendly supplier.

The names of materials presently used in aerospace applications are familiar: magnesium, aluminum, ti­tanium, and so on. Propulsion sci­entists call the ideal material for tur­bine engines “Unobtainium,” be­cause it does not exist. Since Unobtainium is unobtainable, they must develop new materials or work wonders with existing ones. Both broad paths are being followed.

The internal structure of metals and alloys is defined by the method by which they are produced. Thus, casting, rolling, and forging pro­duce metals and alloys whose prop­erties are understood and predict­able. Temperature and strength lim­its are known. However, if the methods of producing alloys can be changed, their internal properties can also be changed—for the better, in this case.

An example is melting the alloy into liquid form, then cooling it at superfast rates of one million de­grees per second. Lockheed calls it Rapid Solidification Processing, or RSP, and visualizes applications primarily in structures and skins of aerospace vehicles operating at high temperatures, such as the Ad­vanced Tactical Fighter, National Aerospace Plane, spacecraft, and missiles. The Pratt & Whitney name is Rapid Solidification Rate, or RSR. P&W aims mainly for applica­tions in gas turbine engines.

With rapid solidification pro­cesses, alloys of known materials can be produced that are capable of use at higher temperatures. Thus, magnesium alloys can replace alu­minum alloys, aluminum alloys can replace titanium, and so on up the temperature scale. In a gas turbine engine, Pratt & Whitney believes that alloys produced by rapid solid­ification can be used in compressor and turbine airfoils and disks to achieve these benefits:

• Fifty percent increase in thrust­-to-weight ratio;

• Twenty to thirty percent re­duced acquisition cost; and

• Three times longer part life in the hot sections.

Other new materials being inves­tigated are not conventional metals as most people know them. Instead, they are composites, such as metal matrices, carbon/carbon or graphite/polymers, or ceramics. Only re­cently, such new materials were un­suitable for engine applications. Graphites are strong, but lose strength as temperatures increase. Carbon/carbons could tolerate tem­peratures, but were not strong. Re­cent developments under HPTET and other programs have developed composites that do not have the ear­lier shortcomings.

Other advances being pursued under HPTET aim at creating inno­vative engine structures. For in­stance, if an engine structure could be designed without bearings, then greater efficiency and reliability could be possible. Doing away with bearings is just one example of the innovative thinking sprouting under the aegis of HPTET.

The scientists monitoring the HPTET program for the Air Force summarize it as “an advanced, ag­gressive plan to meet military pro­pulsion needs for 2000 and beyond. The major thrust is innovation.” They also point out that the search for new materials is not only a US effort. In fact, their assessment is that Japanese and French laborato­ries are ahead of the US in ceramics and ceramic composites.

A scientist at Air Force Systems Command agrees. He points out the danger of investigating only a few promising areas because research funding is limited. According to USAF analyses, the Soviet Union is investigating more than thirty metal matrix materials for advanced appli­cations, while USAF is limited by money shortages to only a few.

But funds will always be limited, except in time of war. But then is ten or fifteen years too late. Risky, ex­ploratory research must be continu­ous if the Air Force is to be ready whenever it is needed. That re­quires spending money. But money can also be saved, especially in the manufacturing process—on the shop floor, between the research laboratory and the skies.

Competition and Collaboration

Competition has become an em­bedded and pervasive fact of life throughout Air Force propulsion development and acquisition. The case of the alternate fighter engine for the F- 15 and F- 16 is well known. But at ASD’s Propulsion deputate, where all propulsion programs come together, the amount and per­centage of competitive obligations have zoomed in the past three years. The numbers tell the story.

In FY ’83, the Propulsion depu­tate obligated $1.415 billion. Of that amount, $89 million was competi­tive, for 6.3 percent. Competitive figures more than doubled in FY ’84. Of $1.414 billion obligated, six­teen percent, or $227 million, was competitive. In the next year, the figures increased to 60.7 percent competitive ($2.095 billion out of $3.446 billion total). For FY ’86, the competitive figure was 73.4 percent ($2.366 billion of $3.225 billion). The goal is ninety percent in FY ’87, then to climb to ninety-five percent by FY ’89.

Collaborative efforts are on the rise, too. For instance, the Air Force is not the only beneficiary of its propulsion work. The US Navy is improving its F-14 Tomcat fight­ers by fitting F 11 engines, thereby achieving higher performance. In fact, USAF is buying the engines for the Navy’s new F-14D models from GE. Propulsion for the Navy’s Advanced Tactical Aircraft of the mid-1990s could be derived from Air Force propulsion advances. That would happen under an agree­ment they made in 1986 to share appropriate technologies on the Navy’s ATA and the Air Force’s ATF programs.

On the leading edge of research, the Air Force has been working since the summer of 1986 with the other military services, the Depart­ment of Defense, and NASA on de­veloping a national initiative for high-performance turbine engine development. The program is still in the organizational stage. It will use the USAF High-Performance Tur­bine Engine Technology initiative as the nucleus. Bringing in the other participants can broaden the finan­cial support base for a national tur­bine engine initiative.

At present, there is little formal foreign participation in USAF pro­pulsion development. In Europe, the hottest new program is the Eu­ropean Fighter Aircraft. The con­sortia were formed in 1986 and are working to develop the engine and the aircraft itself to fly in the mid-1990s.

However, through collaboration and cooperative projects, foreign engine companies are working with their US counterparts. Through those arrangements, technology ad­vances can be transferred to mutual advantage. Air Force developers take a keen interest in such arrange­ments. In a negative sense, the Air Force can prohibit transfer of lead­ing technology abroad. In a positive vein, it can exploit a foreign ad­vance for USAF propulsion sys­tems. The criterion: Do what is best for the US.

A case in point is the USAF eval­uation of the International Aero En­gines V2500 for reengining KC-135 tankers. IAE’s entry into the KC-135 game puts pressure on the GE/SNECMA joint company, CFM International, whose F108 engine is already being fitted on older tankers that become KC-135Rs.

Pratt & Whitney and Rolls-Royce are already partners in the Pegasus engine that powers US Marine Corps AV-8B Harrier jump jets. Pratt & Whitney has joined with Rolls-Royce and France’s Tur­bomeca to sell their RTM 322 engine to the Army and Navy as an alterna­tive to the GE T700 engine in the Blackhawk, Seahawk, and Apache helicopters.

Rolls-Royce, the British engine giant, is determined to widen its business base with US military customers. Its plans includes working with Pratt & Whitney on the Pegasus and RTM 322, as cited. Also, Rolls-Royce will bid to man­ufacture spares as the US services create competition for multiple sources. It is already performing overhaul of GE TF34 engines that power A-10 Thunderbolt us in the UK. With the Navy’s T-45 Goshawk trainer, Rolls-Royce has a US base for its Adour engine. With partners McDonnell Douglas and British Aerospace, it can offer the Gos­hawk to the US Air Force for its trainer needs.

Remember the YF-3 l’s first flight that opened this article? It could be flying as speculated, as the result of an agreement made in September 1986. Rolls-Royce and Pratt & Whitney agreed to study jointly the technology requirements for a su­personic vertical/short takeoff and landing aircraft engine. Their agree­ment followed a 1986 US-UK gov­ernmental agreement to collaborate on such joint studies.

Clearly, an era of unprecedented progress in aircraft propulsion is happening. What flies in the year 2000 will be the product of work being done in 1987. Because of the way the Air Force is managing the progress for its needs, advances in every aspect of propulsion systems can be integrated into existing ones, steadily improving them.

It is an evolutionary revolution that keeps raising the standards and goals with quality products. Higher quality is imperative. To quote Gen­eral Skantze once again: “A mili­tary-industry team that produces low-quality weapons won’t produce very many because the country won’t be around long to need them.”

The Win-Win Deal

TechMod is the nickname for AFSC’s Technology Modernization Program. It is a joint venture between USAF and industry to stimulate the use of new and existing manufacturing technologies and to invest the capital to put them into practice. In TechMod programs, both USAF and the contractor put up money in three phases.

During Phases I and II, USAF injects ‘seed money,” which forms the bulk of the capital. That is used to analyze and identify opportunities. Phase II develops tech­nologies and validates their applications in demonstration. In Phase Ill, the con­tractor provides the investment. That is the time when capital equipment is pur­chased and installed and the processes integrated into production.

The “Win-Win” comes about this way: For minimum investment, the Air Force saves money on engine purchases. The participating contractors can modernize their plants and be more competitive for all customers. The Air Force retains rights to the improvements. Immediate financial rewards to Air Force and supplier can be created. Over the long term, the industrial base is healthier and better able to surge when needed.

Propulsion TechMod managers at Aeronautical Systems Division say the program addresses the entire manufacturing process, from raw materials to engine out the door.” They calculate that for an investment of $132 million over the years 1982-86, potential savings of $750 million to $900 million were created for the Air Force. Examples demonstrate how the program works.

Rotating parts, such as disks and spools, are common to gas turbine engines. The parts are turned on lathes This is a high-volume activity, with high potential for mistakes and defects. The criterion for success is ‘throughput,’ or the number of parts produced that meet specifications. Under the TechMod program, General Electric’s Aircraft Engine Business Group conceived and has developed a Horizon­tal Turning Center at Wilmington, N. C., that is just now going into full use.

The Air Force invested $2.1 million in the project, and GE put up $19.6 million. The payoff? The Horizontal Turning Center will produce 100 percent more throughput and save a million man-hours of direct labor over ten years. The military engine programs that benefit right away from the new center are the F1 01 (B-lB bomber) and the Fl 10 (F-15 and F-16 fighters). Net benefit to the Air Force is estimated at $13 million, or a payoff of better than six to one.

General Electric also wins. It achieves immediate savings. Soon, other GE military engines, such as the Fl 08 (KC-1 35R) and the F404 (Navy/Marine F/A-18), will benefit. The center will also help GE cut costs and be more competitive on a civil engine like the CFM56 (Boeing 737-300 and Airbus A320). That is the “Win-Win.”

Subcontractors also participate in TechMod. Precision Castparts Corp. is one of the major subcontractors in the turbine engine business. Under TechMod, it has pioneered computer-aided design and computer-aided machining (CAD/CAM) in manufacturing large complex castings.

Like rotating parts, complex cast parts are common in gas turbine engines. Most problems with large castings can be traced back to the original engineering design. The process has been somewhat trial and error: design the part, cast it, then try it. Through successive trials, castings are eventually created that are metallurgically sound.

Precision Castparts has developed a CAD/CAM workstation and communications links to transmit casting design data between its plant and its customers. The manufacturing benefits: metallurgically sound castings are produced earlier, with fewer trials. That will cut development costs, improve parts quality, and shorten delivery time. The system will be fully operational by July 1987. Engines to benefit are the Air Force F100, F101, F110, and Navy F404.