The situation was saved by an aggressive young Pentagon action officer, Major John R. Boyd, who led the effort to redirect F-X development to a highly maneuverable aircraft optimized for the air superiority role.… His precepts led to a demand for the F-X to have the capability to outturn and outaccelerate enemy fighters under all conditions encountered in a dogfight.
Walter J. Boyne, Beyond the Wild Blue: A History of the United States Air Force, 1947–1997
Things were looking up for Boyd, or so he thought. He had won several prestigious awards instead of being court-martialed for stealing computer time. His work was hailed as important and had caused the Air Force to pause and reconsider how it designed and procured new aircraft. He had personally briefed many of the top brass (three- and four-star generals) in the Air Force on his findings as a young major. Not bad for a guy with no advanced degrees, little in the way of aeronautical engineering experience, using stolen computer time. But he had broken the rules and screwed with the system. Military bureaucracies in general and the Air Force in particular don’t like people who aren’t team players and who, as the saying goes, “color outside the lines.” The Air Force, in its infinite wisdom, decided to send Major Boyd to Okinawa, one of the few places where his rather considerable talents would not be used effectively. It was also halfway around the world and really out of the way. It would be hard to rock the boat there.
Fate intervened once again. Col. Chuck Myers, a successful test pilot, persuaded his friend Tom Cheatham, in the Directorate of Defense Research and Engineering (DDR&E), to help him undo the original assignment. Myers knew of Boyd’s EM work and convinced Cheatham that they needed someone with his talents in the DDR&E system, where his work on aircraft design could be properly utilized. After they combined forces to lobby Air Force Chief of Staff John P. McConnell, Boyd’s orders for Okinawa were rescinded, and Boyd received orders to report to the Pentagon to work on the evolving F-X project.1
Boyd left Eglin in the fall of 1966 and was assigned to the Operational Requirements Team in the office of the deputy for Research and Development at Air Force headquarters in the Pentagon. It ushered into Boyd’s life a series of big changes. Save for his stint at Georgia Tech, when he was a civilian student, this was the first time in his career when he was not on an Air Force base. He would now fly a desk, not a fighter. Instead of the intricacies of air-to-air combat, he had to learn the ways of the Pentagon. With only a brief interruption for service in Southeast Asia in 1972–1973, it would be Boyd’s home for the next 22 years, 9 in the Air Force and 13 in retirement. The hotshot fighter pilot with bright ideas would learn to change the system. He would also find others who shared some of his maverick views and could assist him in pushing them. Once again, a series of serendipitous accidents prepared the way for Boyd.
Other than flying, it was the best part of his career. Win or lose, he was in combat, and the heat of a different battle was every bit as exhilarating intellectually as the real thing. You had to think quickly and well, or you were dead, at least metaphorically speaking. One is reminded of Winston Churchill’s comment about the difference between politics and war: “Politics is almost as exciting as war, and quite as dangerous. In war you can only be killed once, but in politics many times.”2 Although not as deadly, the stakes were still high: promotions, early retirement, reassignments, public humiliations, and the winning and losing of contracts and policy decisions. The warring parties kept score, but the victories were of a different sort, and so were the defeats—and the engagement was continuous.
Boyd had been reassigned to work on the design of the next-generation air superiority fighter for the Air Force, the project known as the F-X, for Fighter Experimental. Through a series of insights and initiatives over the next nine years, the F-X became the F-15, and the work on the F-15 led Boyd and a coterie of others to push for the development of the lightweight fighter (LWF) that became the F-16. Before one can fully understand the story of the F-X’s transition to the F-15, which in turn spawned the F-16, one needs to understand the context of the debates that these planes and the groups of supporters and detractors represented. To do that, one needs to look at the Air Force between Korea and Vietnam.
The last air superiority fighter the Air Force had designed and used in war was the F-86 designed in 1948. In the intervening years it had designed the century series, but they were not air superiority fighters per se. The Air Force had been forced to accept the F-4 II Phantom, designed by the U.S. Navy, and the Navy’s A-7D Corsair was forced on it by the circumstances of the war in Vietnam. Having to make do with two Navy-designed planes in the early 1960s stuck in the throats of all Air Force pilots. The Air Force was dedicated to the proposition that it would not happen again. To make matters worse, the USAF-designed F-111, son of the McNamara-ordained TFX (Tactical Fighter, Experimental), was to be a joint Air Force–Navy fighter-bomber.3 The Air Force procured its version, the F-111A, but the F-111B for the Navy was eventually canceled. The leadership of the Air Force vowed that the Navy would not sucker them again. They would design their own air superiority fighter.
Meanwhile, making do with the F-100, the F-105, and the F-4 in Vietnam proved less than satisfactory. The loss ratios against both North Vietnamese and Soviet pilots were not good. In fact, they began at 1:1 in 1965 and overall were far less than the 10:1 ratio in Korea. From 1 April 1965 to 1 March 1968, despite some interludes of great success, the United States had an exchange ratio in air-to-air combat of 2.4:1.4 Why were U.S. planes and pilots performing so poorly?
That is a complicated story requiring detailed analysis that cannot be fully explored here. Numbers, tactics, capabilities, and rules of engagement changed on both sides throughout the air war in Vietnam. Making summary judgments of much breadth or over a long time frame invites serious error. There were several general reasons for lack of success early in the war. First, many U.S. pilots were not being taught maneuvers to elude surface-to-air missiles (SAMs). Second, aerial dogfighting was for many a lost art. Third, the F-4 Phantom originally had no gun, and the pk (probability of a kill) ratio of air-to-air missiles was far less than had been hoped. The missile pk rate (combined for Falcon, Sparrow, and Sidewinder) from 1 April 1965 to 1 March 1968 was only 11.8 percent.5 This situation improved dramatically as the war progressed. The United States also developed better missiles with improved seekers, greater BVR (beyond visual range) range and accuracy, and increased front-aspect capability leading to the solid performance with the AIM-9L after Vietnam. Vietnam represented an important testing ground on many fronts.
Fourth, as Boyd’s energy maneuverability studies had shown, U.S. planes were at a disadvantage in certain encounters against their Soviet counterparts. They simply were not as agile as the enemy’s lighter, quicker fighters. Fifth, we were not permitted to take out the North Vietnamese bases and continued air strikes with large packages into North Vietnam regardless of risk and loss. Sixth, the enemy proved adept at developing tactics that virtually guaranteed U.S. air losses. These included selective defense in mass, MiG-17 use of low-altitude wagon wheels to eliminate the threat from the Sparrow missile, use of ground control intercept radar for MiG-21s to attack U.S. strike packages from the rear at high speed, and a variety of other tactics, techniques, and procedures that made life difficult and dangerous for American pilots.6
Throughout 1965, as Vietnam heated up, so too did concern for the next fighter for the U.S. Air Force. The F-4 Phantom was the primary air superiority fighter of the 1960s and 1970s, but there were problems with it. It began life in 1953 as the Navy’s proposed fleet air defense plane. When it entered service in 1963, the Air Force had been ordered by McNamara and company to buy it to save money. No Air Force pilot worth his salt was going to have another Navy plane as an Air Force fighter, just on principle. The F-4 looks nasty, not graceful or elegant at all. It looks like the brutish war machine that it is. It is big and heavy (nearly 30,000 pounds empty, almost 60,000 pounds gross weight). Original versions had no gun, and it had to rely solely on missiles for its kills. It had poor visibility, and its engines gave off plumes of heavy black smoke, making it easy for enemy pilots and ground gunners both to detect it. It was the antithesis of today’s quest for stealth. It entered combat in Vietnam in 1965 and, through January 1973, was credited with downing 107.5 enemy aircraft, more than 40 of which were obsolescent MiG-17s and 19s. In the same period, there were 362 F-4 losses, nearly 300 of which were lost to SAMs.7 The plane had been a disappointment, the design was old, and the Air Force needed a new fighter—soon.
In 1967 the newest plane about to enter the Air Force inventory was the F-111. It was a curious plane that had variable-sweep wings: straight for range, swept back for speed. It emerged from the McNamara-inspired TFX concept but came to be more of a nuclear bomber in the interlude before the Advanced Manned Strategic Aircraft (which became the B-1) would come on line. It had a gross weight of 92,500 pounds and a range of 3,400 nautical miles unrefueled. It was nearly four times as heavy as the F-5 and nearly five times as large. The follow-on to the F-111, the F-X was presumed to be similar in design. That is, it would be a large, two-seat, two-engine, heavy (80,000 pounds gross weight), variable-sweep wing, multirole fighter-bomber. Just why that should be so was not really questioned. There were problems in the early design phase, however, and because of his work with energy maneuverability, Boyd was called in to review the project and assist in the design of the F-X. His response to the challenge was noted in the previous chapter. Now he had to make good on it.
In his quest to make the F-X a better fighter, Boyd was aided by a group of others who held similar views and had done much to prepare the ground that he then plowed. Chief among them was the almost equally flamboyant fighter pilot Chuck Myers. Myers and a series of others, both military and civilian, inside and outside the Pentagon, Air Force and Navy, who believed in the need for a true air superiority fighter, were active in the period 1961–1965, before Boyd ever got to the Pentagon. They formed an alliance that became known as the Air Superiority Society, ASS for short (female associates were known as ASSETS). They used to meet at the Windjammer Club on the top floor of the Marriott Hotel, just off the Fourteenth Street Bridge and across the highway from the Pentagon in Arlington.
Myers, a rough and ready sort who cuts to the chase and minces no words when asked for his opinion, is rare among pilots. In World War II he flew B-25s for the Army Air Forces. During Korea, he was in the Navy and flew F9Fs from the carrier Bonhomme Richard. He then became a professional test pilot and flew helicopters as well as the most advanced fighters and attack aircraft for General Dynamics and Lockheed. Few could match his range of flying skills, his combat experience, and his considerable insight into the requirements for successful air-to-air combat.
While with Lockheed, he became involved in marketing as the company competed with General Dynamics for the TFX (F-111). Myers became convinced of the need for an air superiority fighter for a nonnuclear war. As he explained, “The DOD requirement produced an airplane that was pushing 80,000 pounds—almost two and a half times heavier than a World War II B-17—and was expected to perform five separate missions: air superiority, close air support, all weather attack, nuclear attack, and all weather intercept. What’s more it was going to do it for two different services.”8 It was only logical that a single aircraft could not perform all these missions as well as five different airplanes each designed to accomplish a single mission. The problem was that the Air Force couldn’t afford to buy a separate plane for each mission. Hence, aircraft tended to become multirole so that one aircraft could perform multiple missions. Worse still, under the systems analysis and micromanagement regime of Secretary of Defense Robert McNamara, the TFX was supposed to be used by both the Navy and the Air Force, requiring further trade-offs. Following those injunctions, both services were likely to get a plane that could perform all the missions marginally, but none of them really well.
In doing interviews for his book The Pentagon Paradox, Jim Stevenson tells of interviewing Myers. Stevenson asked Myers why he thought it was wrong for a contractor to provide what a military service requested. After all, Stevenson queried, why is it up to the contractor to tell the military what kind of aircraft it should have? He likened the relationship to that between a customer and a prostitute: although the prostitute may not approve of the request, her job was to provide the customer with whatever services he wished to purchase. Myers shot back that the analogy was flawed: “A hooker can do all that,” the implication being that a defense contractor could not.9
Myers, along with J. Ray Donahue (another legendary character who then worked for Litton) and others, began proselytizing for an air superiority fighter. J. Ray had access to God and everybody, or so it seemed, and after schmoozing a bit with senior Air Force leaders about the wife and kids, he’d turn and introduce Chuck and tell whomever the victim of the day was that he should listen to what Myers had to say. Some listened, some didn’t. One who did was Maj. Gen. Arthur Agan, at the time the assistant deputy chief of staff for Plans and Operations. Myers persuaded him to convene a panel of World War II and Korean War aces in December 1964 in an attempt to specify the most important characteristics for a fighter. As a result, a paper was produced in 1965 that underscored the need for an air superiority fighter, not some multimission hybrid.
Early in the Vietnam War, two older MiG-17s used gunfire to shoot down two USAF F-105s, the newest planes in the Air Force inventory, during a bombing run on the Than Hoa Bridge on April 4, 1965. Despite the tactical rules of engagement in the operation and the extenuating circumstances, it was a shock to the Air Force. For such obsolescent planes in the Communist inventory to take out two F-105s was unacceptable. General McConnell, Air Force Chief of Staff, issued a document entitled “Air Force Doctrine on Air Superiority.”10 The paper laid out in detail what was required to achieve air superiority and what capabilities a fighter should have to accomplish that mission. Among other things, it stated:
1. The air superiority element of airpower needs to be more clearly understood and more positively considered in our plans, our definition of force characteristics, and our conduct of operations. The following Air Force doctrine on air superiority is provided as guidance to all members of the United States Air Force.
2. Definitions
a. Air superiority is “that degree of dominance in the air battle of one force over another which permits the conduct of operations by the former and its related land, sea and air force at a given time and place without prohibitive interference by the opposing force.”
b. Air supremacy is “that degree of air superiority where the opposing air force is incapable of effective interference.”
Contained within this document are the seeds of the controversy surrounding the ill-fated F-X and what eventually became the debate over the lightweight fighter. Often misconstrued as a simple quality versus quantity debate, or high technology versus low technology, the issues are more complex, the nuances more subtle, than such statements suggest.
One small group of smart, well-connected, and knowledgeable advocates sought to design what they thought the Air Force most needed: a small, fast air superiority fighter. They based their arguments on paragraph 8 of McConnell’s air superiority paper: “To assure that we can gain air superiority, we must provide and train the proper forces. We must be prepared to win air superiority. We must not assume it. We need at least one—preferably two or all three—of the following interdependent advantages: numerical superiority, tactical superiority (including training), and technical superiority (e.g., aircraft performance).” Boyd wanted to meet all three criteria. His work at Nellis on Aerial Attack Study had focused on superior training of pilots for attaining combat skills. His work on energy maneuverability had focused on carefully measuring aircraft performance. He could determine the technical design features and the comparative performance characteristics through careful trade-off analyses needed to customize the combination of attributes desired. He would come to believe that large, heavy, two-engine, advanced, radar-dependent fighters were simply too expensive to be purchased in sufficient quantity to guarantee air superiority. If the Air Force wanted sufficient quantity, the planes had to be cheaper than the F-111, F-X/F-15 aircraft on which it was now focusing. This was the essence of the argument made by what came to be known as the Fighter Mafia, the group that championed the lightweight fighter that became the F-16.
The other group, far larger and representing the conventional wisdom of Air Force leadership at the time, sought a large twin-engine, multirole aircraft based on the design of the F-111. Bombing the enemy into submission was the only appropriate way to win. This group sought to emphasize paragraph 10 of McConnell’s letter: “Enemy airpower is destroyed in two ways: in the air and on the surface. Both methods are essential parts of counter-air operations and should be carried out concurrently.” This argument is as old as airpower itself, going back to Douhet’s 1921 contention in Command of the Air that it is better to kill the birds in the nest than in the air. The faith expressed by British prime minister Stanley Baldwin in 1932—“The bomber will always get through”—remains undiminished despite evidence to the contrary. On the other hand, the combination of stealth, precision, and stand-off capability has greatly improved air-delivered ordnance in the 1990s.
What was really at issue were assumptions about how to achieve air superiority. Was offensive counterair to be accomplished by bombing enemy aircraft on the ground or by dogfights in the sky using air-to-air strategy and tactics? To the first group, destroying enemy forces on the ground was preferable to wresting air superiority in the skies over the battlefield. To the second, virtue lay in designing air-to-air fighters primarily to destroy aircraft in the air. The latest edition of the Historical Dictionary of the U.S. Air Force characterizes the debate this way: “One school contends that the mission [air superiority] can be accomplished on the forward edge of the battle by tactical strikes of more numerous but less expensive aircraft. The other suggests the more traditional deep penetration attack against enemy airfields and staging areas. This would require fewer, highly sophisticated fighters capable of surviving in a high threat environment. Recent designs suggest a balanced force capable of both approaches.”11
The debate continues, though the bombing faction maintains that the Gulf War has determined the victor. The experience in Kosovo shows mixed results, with the bombing of infrastructure highly successful but the destruction of fielded forces decidedly less so. The crux of the matter is that the justification for the existence of the U.S. Air Force has been built on strategic bombing.12 There has been a shift, however, in Air Force leadership and emphasis from bombers and Strategic Air Command to fighters and Tactical Air Command.13 Many, chief among them Eliot Cohen, suggest that the jury is still out.14 As the experience in Kosovo suggests, the debate rages on. Others, such as Robert Pape in his recent book Bombing to Win: Air Power and Coercion in War, state flatly, “Strategic Bombing Won’t Matter in the Future.”15
Along the way, the urgency of the quest for an air superiority fighter was intensified by external events. The Six-Day War between the Israelis and the Arab world in June 1967 illustrated the need for control of the air. The Israeli preemptive strike successfully destroyed the bulk of enemy air forces on the ground and showed the importance of obtaining and maintaining air superiority from the outset of a war. The Israeli Air Force destroyed roughly 260 of the Egyptians’ 340 combat aircraft in the first few hours of the war. It later destroyed large numbers of the Jordanian, Iraqi, and Syrian air forces as well. Israel’s enemies lost 368 aircraft. Israel lost 40 aircraft in the war (only 2 in air-to-air combat) and achieved an air combat exchange ratio of 1 to 25. It was a stunning example of the importance of air superiority achieved in both ways.16
The next month, the U.S. Air Force received a wake-up call. At the Domodedovo Air Show outside Moscow in July 1967, before the world’s press, the Soviets showcased their new generation of combat aircraft. Two aircraft in particular caused a stir, both from the Mikoyan-Gurevich (MiG) design bureau: a swing-wing fighter with the NATO code name Flogger (the MiG-23) and a high-speed, twin-fin fighter called the Foxbat (the MiG-25). A ground-attack version of the MiG-23 appeared slightly later and was designated the MiG-27, or Flogger D in NATO parlance. The MiG-25 Foxbat was clearly superior to the F-4 Phantom II in top speed and altitude and a leap ahead in the race to achieve air superiority. If the Air Force had needed any more incentive to push for its own air superiority fighter, the Domodedovo Air Show supplied it.
The specification, design, development, and procurement of tactical fighter aircraft is a lengthy and complicated process. The F-X project had begun in April 1965 with the concept formulation phase for a multipurpose fighter at Wright Patterson Air Force Base, by the Aeronautical Systems Division under direction of Air Force headquarters. In October 1965 the Air Force asked for full funding of full-scale studies and two months later issued a request for proposals (RFP) for a “Tactical Support Aircraft.” That term suggested a lack of focus on air superiority within the Air Force, McConnell’s letter notwithstanding. “Tactical support aircraft” did not sound like an air superiority fighter.
Tactical Air Command’s first stated requirements for the new plane were released in the Qualitative Operational Requirement. Out of thirteen potential contractors, three were selected for initial funding: Boeing, Lockheed, and North American Rockwell. McDonnell Aircraft was one of the losers at this stage. Grumman Aircraft, though unfunded, opted to remain in the chase for the lucrative contract by funding its own study. The results of the contractor studies became the Concept Formulation Package (CFP), which was not submitted to the DDR&E until June 1967. The CFP was a detailed description of the F-X’s purpose, its performance characteristics, and conceptual configurations for avionics and so forth.
There were many problems with and debates about some of the most basic aspects of the proposed plane’s design. These included size (both overall dimensions and gross weight), swing-wing versus fixed-wing design, versatility (the plane’s ability to perform multiple missions and the relative priority among them), crew size, avionics configuration, lead times for state-of-the-art technologies to be incorporated, and estimated costs. None of the original designs submitted were considered further because of problems with aerodynamic configurations and engine bypass ratios. Additionally, the Navy was proposing a VFAX fleet defense fighter in the same time frame, and the issue of commonality—son of the TFX—reared its head again. There were many bruising battles within the Air Force, with the Department of Defense, and between the department and Capitol Hill, but little happened formally between the summer of 1966 and the autumn of 1967.
The F-X was to be both the replacement for the F-4 and a follow-on to the F-111. Studies began in 1965 to design the Fighter Experimental. The relationship between its missions—air superiority and ground attack—was not entirely clear, as the difference in the program designation and the RFP suggests. Into all this walked Maj. John Boyd and his energy maneuverability studies. On his arrival at the Pentagon, he started immediately to do trade-off studies focusing mainly on the thrust-to-weight ratio. For nearly all concerned, the swing wing was considered the wave of the future. Everyone, or so it seemed, was thinking in these terms, including Boyd. “Almost an afterthought” is how Jeff Ethell describes Boyd’s approach to the fixed-wing option:
He wondered what the trade-offs would look like for a fixed wing.… he began to think about the aerodynamic benefits versus the structural penalties in variable sweep wing. As it turned out Boyd started a whole new investigation into fixed wing versus swing wing. All the contractors except Northrop were in favour of the swing wing, but what began to emerge was a structural penalty for swing wings much larger than generally admitted, increasing as the fighter manoeuverability requirements increased.17
Eventually Boyd began a series of comparisons of the increased weight of the pivot structure for a swing-wing plane and the associated increased weight, drag, and fuel requirements versus another single wing-position design. The outcomes were dramatic and obvious. The F-111 design concept in the F-X was not only much more expensive, but it also was not as good in many of the critical performance parameters as some other design concepts. The F-X would have to be radically altered. Hundreds of different shapes, sizes, and wing loadings were compared, and thousands of hours of wind tunnel tests were run on them; all combined to prove that a fixed-wing design was the way to go.
Boyd’s EM work had shown many shortcomings in existing Air Force aircraft and the need to build maneuverability into the design. The methodology suggested ways to analyze the trade-offs of one performance characteristic against another and its cost in increased weight, additional thrust, wing loadings, fuel requirements, and so on. These trade-off analyses—painstakingly difficult and refined assessments of various performance characteristics and design modifications—were the critical factor in shaping a wish for an air superiority fighter, the F-X, into a reality, the F-15. They represented a mammoth undertaking, comparing each flight characteristic and design configuration against all others in successive pairs and computer runs until a composite picture could be formed of the relevant data and the trade-offs affecting weight, size, and performance of different types under specified conditions. It was classical scientific method in action. All the permutations and combinations of hypotheses were tested. Boyd was relentless in pushing for them and using them to refine the best possible design concept for the F-15.
Designing and building the F-15 was a massive, complex, decade-long project with many major contributors and hundreds of participants in the design process, in both the Air Force and industry. I do not wish to suggest that Boyd was the sole designer of the F-15. Hundreds of people in the Air Force (such as Lt. Col. Larry Welch, later Chief of Staff of the Air Force) and industry (such as McDonnell designer George Graff) were intimately involved in the design of the F-15 and contributed significantly to the final product. Indeed, most of the senior leadership of the Air Force contributed to the project as best they could because it was the major aircraft procurement of their era. More than that, it would be the backbone of the Air Force for the next 40 years. Boyd, however, provided the analytical framework that allowed the F-15 to emerge from the hodgepodge of competing preferences. His studies eliminated the swing wing and reshaped the basic design, and those same studies did much to refine the design process and help make the thousands of choices that resulted in transforming the F-X concept into the F-15 fighter.
Boyd had never designed an airplane before, but as he told Colonel Ricci and Gen. Casey Dempster, “I could fuck up and do better than this.” The key was to come up with a rational and objective means (as opposed to personal, political, or professional interests) to assess the myriad aircraft sizes, configurations, avionics packages, and capabilities proposed by all involved. Among those participating in the decisions, some had political clout, some technical expertise, some combat experience. There were few with all three. The trick was to explain the parameters to all in terms they could understand so some logic could be brought to the process.
Another officer involved in the F-15 development process described it this way:
Col. John R. Boyd perfected a novel method of employing computers for parametric trade-off studies to achieve better visibility on optimum design parameters. The trade-off study technique was an invaluable tool in determining impact of or deleting features on the size and weight of the “rubber” conceptual design of the F-X. Those who proposed nice-to-have features or “innovative ideas” for improving weapons system capability could readily see from the trade-off studies how the increased weight would adversely affect wing loading, acceleration, and performance. The trade-off, if these factors were held constant, would be a larger, more complex, and costlier fighter. The parametric study technique was used as a common method by contractors participating in the point design study in presenting the results of their efforts. These studies were very effective in educating the unknowledgeable and in successfully completing the advocacy of the F-X program in Congress and the Pentagon.18
So Boyd’s methodology helped bring some rationality to the design process. It was a process of analysis, education, and advocacy combined. It was also the test bed for the same sorts of design techniques that would later be used on the F-16.
There were numerous aspects of the development of the F-15 in which Boyd had a direct role. Given space limitations, only a few examples will have to suffice. Realizing that the hardware on the F-4 that got the plane from Mach 1.7 to 2.0 had zero utility in actual combat, Boyd sought to eliminate the variable ramp inlets and associated bellmouth mechanisms on the compressor faces of the engines. They were deadweight and unnecessary complexity. Boyd sought a maximum speed of Mach 2, the Air Force Mach 3.0. The compromise was needlessly high at Mach 2.5. In that most air-to-air combat occurred at subsonic speeds and rarely above Mach 1.5, the costs and design penalties for the higher speed would seem largely unnecessary. Boyd lost on the top speed requirement to the Air Force for the F-15 and the variable ramp inlets. The higher speed requirement caused great difficulty with the engines, however. Cockpit visibility for improved situational awareness also was important, and Boyd demanded a standard as good as or better than that of the F-86. His success on this is greatly appreciated by all who fly the F-15. According to Barry Watts (a retired Air Force officer and industry analyst), “Boyd wanted to go with slats for high-g maneuvering, McDonnell preferred a rolled camber wing, and that’s what’s on the F-15 to this day. The issue was a trade-off between drag and complexity (although slats had worked perfectly well on the F-86 and are used on the F-16). The added drag of the rolled camber wing is something the F-15 has to haul through the air on every mission, just like the F-4 was foolishly burdened with variable ramps and engine bellmouths.”19 Those are just a few examples of Boyd’s contributions, or attempts at them. There were some successes, some failures, but overall, what emerged was a far better product than would have occurred if his methodology had not been applied.
Some of the ideas that improved the F-15 were a result of Boyd’s analysis, but others got credit for them. Several observers of the process reiterate that Boyd’s competitive personality, dogged fixation, and pugnacious style became his own worst enemy. So some of Boyd’s ideas were carried forward successfully by others. He didn’t mind, and neither did they. The final product was better for the effort, and that is what counted in the long run.
Everyone even remotely involved had a pet idea, new concept, favorite piece of hardware, or technical gadget to affix to the F-X. Disagreement on the basics was bad enough, but every new notion, however silly or improbable, had to be beaten down or accepted in the long, arduous process of shaping the F-15 conceptually, before any production and the modifications that inevitably follow in that phase. One proponent wanted a trainable gun. Another wanted a helmet sight. New highly maneuverable short-range missiles vied with long-range BVR kill capabilities. Without some actual data provided by Boyd’s assessment techniques, the plane would have been reduced to the lowest common denominator of agreements on a wide range of engineering and political pet rocks. In retrospect, it is amazing that the plane turned out to be as good as it is.
What emerged eventually was the F-15. Col. Everest Riccioni, Boyd’s boss and ultimately friend and coconspirator on the F-16, assessed Boyd’s accomplishments in a long memorandum in 1971. Boyd took on the original F-X concept, a follow-on to the F-111, and systematically analyzed all aspects of the proposal. He found the original proposal for a 62,500-pound variable sweep wing aircraft to be “overweight, under-winged, overly expensive, overly complex, ineffective”20 and not in the best interests of the Air Force. Criticizing the design assumptions or preferences while saving the concept of the F-X (avoiding throwing the baby out with the bath water) was a neat trick. Boyd proceeded to take on each aspect of the design and do a complex series of trade-off analyses comparing each element to the others to derive the optimum performance for the specified mission of the F-X/F-15.
The Air Staff position on the basic design parameters for the F-X when Boyd was first asked to review it called for an airplane that weighed 62,500 pounds with a thrust-to-weight ratio at takeoff of 0.75, a wing loading of 100 pounds, and a turbofan engine with a bypass ratio of 2.2.21 Boyd’s first cut in his trade-off studies revealed that the more appropriate characteristics were a weight of 40,000 pounds, thrust-to-weight ratio of 0.97, and wing loading of 110 pounds per square foot. Wing loading is the ratio between the surface area of the wing and the load it has to support. Boyd was suspicious of high wing loadings and undertook a series of extensive trade-off analyses regarding wing loading and maneuverability. Doing so required extensive study of drag polars and revealed that an even better solution would be a wing loading of 80 pounds per square foot and an engine bypass ratio of 0.9. At that point it became clear that light wing loadings were competitive with variable sweep wing configurations. Boyd determined that a fixed-wing design with a wing loading of 60–65 pounds per square foot had definite combat advantages over the preferred swing-wing design, and the savings in weight and cost were substantial.22
Boyd and his colleagues also anticipated the Navy’s move from the fighter attack VFAX concept to the air superiority F-14. Boyd prepared a memo for Gen. L. L. Wilson on this and a briefing on methods for countering the Navy ploy and discouraging commonality (as with the F-4 and supposedly with the F-111). Boyd was also concerned about a declining defense budget and increasing unit costs of the emerging F-15. He used his trade-off studies to show the weight, performance, and cost consequences of several fashionable and expensive but often only marginally effective additions to the F-15. Boyd’s consistent, hard-nosed questioning and analysis of nearly every aspect of the F-15 program (concept definition, basic engineering, performance characteristics, unit costs, service rivalry with the Navy, congressional approval for procurement) were largely responsible for the definition of the F-15, its survival, and its outstanding capabilities. No one else had as much to do with the definition of the F-15 as Boyd.
Boyd was critical of the system’s assumptions and preferences but supportive of the need for an air superiority fighter. He had to keep saying no to the swing-wing, large F-111 follow-on because it was not capable of performing the mission. Saying so (repeatedly) and having to prove why (repeatedly) took courage and integrity. It made him many enemies. His detailed analyses and trade-off studies using energy maneuverability theory (and the improvements he was making to it along the way) led him to save the concept of a capable multirole fighter while transforming the airplane that nearly everyone had envisioned as the end product. Boyd knew that the supposedly optimum proposed solution for the F-X was a loser on two counts. First, it would be so expensive that Congress might never fund it. Second, even if it were procured, Boyd’s EM analyses showed that existing aircraft in the Soviet inventory could defeat it. That was simply unacceptable to all. New solutions were required.
By March 1967, the Air Force had clarified its criteria enough to ask contractors to aim for a speed range of Mach 1.5 to 3.0, a large window. It left it to the contractors to make the case for swing or fixed wing, single crew or two. In September 1968 the F-X Concept Development was authorized and an RFP for contract definition offered to the aerospace industry. Eight contractors bid for the contract, but by December 1969 only McDonnell Douglas, Fairchild-Hiller, and North American remained in the running. By now the F-X had become the F-15. The USAF Development Concept Paper, as Michael J. Getting summarizes it,
defined the overall parameters of the design, and justified it against pressure from the US Navy to take a modified version of their VFAX/F-14 on four counts: it would be a single seat, fixed wing, twin-engined fighter of approximately 40,000 lbs (18,000 kg); there would be no competitive fly-off, as this was not thought desirable; the VFAX was not considered a suitable replacement for the F-4E Phantom, nor could the F-4E be modified to meet the threat; and an air-to-ground capability would be included, but only as an off-shoot of the primary air-to-air role.23
In case there was any doubt, it stipulated that the F-15 was to be “optimized for counter air missions.” Furthermore, it was to be “superior in air combat to any present or postulated Soviet fighters both in close-in, visual encounters and in stand-off or all weather encounters.”
Thus stipulated, work on the F-15 progressed. It had begun in October 1965 with the F-X Study. Four years later, a design was selected in December 1969. The first aircraft was delivered to TAC in November 1974. By today’s standards, the time frame of less than a decade looks pretty good. If and when the F-22 (the advanced tactical fighter) flies, it will have taken 30 years from the first plans (1979) to the initial operating capability (projected 2008). Throughout the F-15 development process, Boyd had been analyzing the trade-offs to shape a better plane with better performance and lower cost. Ultimately, he decided his efforts were not good enough. His ideal F-15 was even smaller, more maneuverable, and less expensive. The Air Force wanted what it wanted, the logic of Boyd’s analyses be damned, and he was ordered to stop further studies on the F-15. In effect, Lt. Gen. Otto Glasser fired him from the project, but Boyd hung on, knowing that his techniques were necessary to complete the program.
The F-15 Eagle is undoubtedly the world’s finest fighter and a superb attack plane as well. Its combination of speed, range, maneuverability, radar, missiles, and gun make it a deadly foe in the air. Its roughly 48,000–58,000 pounds of thrust (depending on the variant of the twin engines) give it record-breaking climb and acceleration. Air Force captains David R. King and Donald S. Massey have summarized the Eagle’s record: “The F-15 program has become one of the most successful aircraft development and procurement programs in Air Force history. Although mishaps have claimed a number of F-15s, and two F-15Es were lost to ground fire during operation Desert Storm, the F-15 has triumphed in 96.5 aerial engagements without the loss of a single aircraft.”24 That is an unparalleled record of success.
As a result of the many trade-off analyses and thousands of hours of wind tunnel testing, the plane has outstanding maneuverability. Lt. Col. Jerauld R. Gentry gives much of the credit for the “fact that the F-15 has much higher maneuvering performance than any previous fighter in the world … to John Boyd and his unprecedented tradeoff analyses. He did, however, have some serious reservations about the final F-15 design and equipment decisions, a number of which were made despite the evidence of his tradeoff analyses.”25 After initial engine and stall problems, it has been refined and finely tuned. Its powerful long-range radar can detect targets at 100 miles and, from above, distinguish targets from ground clutter. Its mix of infrared and radar guided missiles as well as a high-speed Gatling gun cannon make it the world’s premier fighter. In a tribute of sorts to weight reduction, it now flies with ballast in the nose to compensate for new generations of digital avionics, which are far lighter and take up less space than earlier versions. Its only drawback is its price. The best is expensive. But the United States is lucky to have it, and so are those of our allies who could afford to purchase some.
Boyd knew that whatever the specifications of the first version of the plane, the future modifications would only grow in weight, complexity, and price. He was right. The F-15E Strike Eagle, the last modification of the F-15, has a dry weight of 32,000 pounds with a maximum gross takeoff weight of 81,000 pounds. The price is more on the order of $35 million per plane. What the Air Force really needed, thought Boyd and the Fighter Mafia, was a new lightweight fighter that would be faster, more agile, and, most important, cheaper than the F-15. They also wanted a simpler plane with higher reliability. While they didn’t eschew high technology, they wanted to select those technologies carefully.
As Riccioni explained it, “The number of weapons systems that can be employed in battle varies inversely to the square of the level of sophistication.”26 There could be too much of a good thing, and if complex systems don’t work, paying for them has produced no real benefits. So it was that the F-15 and the work on it inspired Boyd, Pierre Sprey, and Rich Riccioni to lead the fight for a lightweight fighter. The F-16 was anathema to the leadership of the Air Force, but it was the essence of an air superiority fighter to its supporters. They wanted two to three times as many lightweight fighters as F-15s, so the two fighters could be used in combination in what came to be known as a hi/lo mix. The battles over the lightweight fighter would echo through the halls of the five-sided wind tunnel for years.