Imagine the fate of air dominance to be determined, not by technology, but by the sex appeal of a perfectly executed barrel roll and the baiting pitch of a pitchman. The tale of the Northrop YF-23, the ghost plane that too many think outdid its competitor in stealth, speed, and range, still haunts the realm of military aviation particularly now that the U.S. Air Force turns to the Next Generation Air Dominance program for solutions the YF-23 once delivered.
The 1991 Advanced Tactical Fighter fly-off between Lockheed’s YF-22 and YF-23 was, on paper, a duel of technological wonders. The YF-23, with its thin, near-extraterrestrial lines, reflected a new vision of survivability: all-aspect stealth, superior range, and the ability to supercruise fly supersonic without afterburner. In the opinion of one analyst, “The YF-23 was faster and stealthier, but the YF-22 was rated as being more agile.” The YF-23 design focused more on evasion than dog fighting, using a broad-spectrum stealth profile that reduced radar reflection from all directions, not just the front. Its engines were buried and covered, reducing its infrared signature a pioneering move as air combat today relies more on IRST systems alongside radar.
The YF-23 supercruising capability was not theoretical. “Of the two aircraft, only YF-23 ever supercruised and that was the prototype with the GE F-120 engine – the engine that lost in the competition to the Pratt & Whitney F119 – even though it demonstrated better performance”, said James Stevenson, a veteran analyst of stealth fighters. This is relevant to one of the repeated patterns in U.S. fighter procurement: risk aversion. Even though the F120 was an advanced variable-cycle engine design that provided high thrust and efficiency, the Air Force ended up with the more traditional F119, a pattern of favoring established technology over extreme innovation that has characterized development of U.S. military engines for decades. Case histories indicate that even in the case of what would become the F-22 program, in which the air force was explicitly trying to develop a generational leap in capabilities, the service eventually selected the more conventional engine over more innovative but riskier options.
The YF-23’s stealth was not merely a matter of shaping. Its exhaust system, for instance, was crafted so as to reduce both its radar and heat signatures, a capability that would prove very valuable when AESA radars and IRSTs became mainstream. Fifth-generation fighters of today such as the F-35 and J-20 use integrated stealth, sensor fusion, and next-generation radars to operate in sensor-rich skies. The YF-23 had anticipated this shift, with its “delta diamond wings and V-tail surfaces” making it have a radar cross-section so minimal that even long-range over-the-horizon sensors could hardly detect it. Its missile-carrying internal bay and massive fuel storage were to be optimized for long-range, high-endurance missions abilities now at the heart of NGAD’s design.
And the YF-23’s collapse was not an engineering failure, but institutional culture. So-called “fighter mafia”- proponents of in-close dogfighting were still the norm in Air Force attitudes. Test pilot Paul Metz, who flew both prototypes, was one of the few to do so. He described, “Northrop’s YF-23 team was made up of brilliant engineers… but they also saw that they ‘thought and spoke almost exclusively in engineering terms.’ Meanwhile, ‘Lockheed infused far more marketing, salesmanship, and pizazz lasting impressions into their YF-22 flight demonstration program.” The YF-22’s wow factor and hard-pressing missile shots captured hearts, but the YF-23 conducted itself silently with the type of survival and reach that would become typical of air warfare in the future.
The actual selection process itself was telling. “The purpose of the fly-off that selected the YF-22 was supposed to validate which design most comprehensibly met all the major requirements. These were stealth, an AESA radar and the ability to supercruise,” Stevenson said. “But the YF-22 demonstrated none of these. Neither the stealth characteristics nor the radar were prepared enough for demonstration.” In effect, the Air Force “selected an empty prototype an ‘aerodynamic paint job’ and then said to the contractors ‘now go develop the aircraft.'”
The choice had profound implications. The F-22 Raptor, though a great air superiority fighter, turned out to be costly and trouble-prone to fly, with less than 200 produced well short of the original dream. Its stealth coating and code required constant maintenance, and its range and endurance, as good as they were, weren’t optimal for the vast Indo-Pacific region now at the center of U.S. strategic thinking. The YF-23, on the other hand, was “designed for range and endurance,” with mission profile and radar signature that appear optimized for 2025 and beyond threats in an A2/AD network and sensor-fusion environment.
The YF-23 experience is not forgotten by engineers today. As the NGAD program develops, most of the YF-23 design advancements adaptive engines, modularity, extreme stealth, and first-look, first-shot, first-kill emphasis are being revisited. “The YF-23 airframe was capable of accommodating many of the design features being sought after in the NGAD program today modular design, adaptive engines, optionally manned capability, and extreme stealth all were potential in the YF-23 airframe, if not demonstrated,” an analyst said.
Ultimately, the YF-23’s history is a cautionary tale of what it means to play it safe where doctrine and technology converge. Its genealogy is carried on in the design of the next generation fighter, a reminder that in flight as in innovation, courage is as vital as ability.
