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).
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.”