The vast majority of Americans hear the words “American stealth planes” and immediately imagine the F-117 Nighthawk, B-2 Spirit, or F-22 Raptor. Lost in the historical backwaters, however, is a considerably lesser-known test plane that didn’t see battle but did make an overwhelmingly significant contribution—the Boeing YF-118G, or the “Bird of Prey.”
Developed in the 1990s in complete secrecy at the top-secret Groom Lake test site, Bird of Prey was never intended to fight its way onto the battlefield. Instead, its purpose was far more sinister: to develop and hone advanced stealth technology and cost-reduced production methods, some of which would trickle down and influence the next generation of weapons systems.
The project also coincided at a high-pressure time for McDonnell Douglas. Having failed on big-ticket bids at the Pentagon like the Advanced Tactical Fighter competition, the company required some way of proving it could innovate in a changing aerospace industry. Phantom Works, the research and development division of the company, challenged it in 1992 and set out to develop something new and useful.
The project was supervised by Alan Wiechman, a stealth expert, who had previously been a part of the F-117, and his consistent guidance allowed American stealth technology to stay far ahead of the competition.
Contrary to the humongous budgets typical of government projects, the Bird of Prey was manufactured on a mere $67 million. The engineers employed rapid prototyping, computer modeling, and creative engineering use of available components. Its powerplant was taken from a business jet, its ejection seat from a Harrier, and cockpit controls from past generation fighter aircraft. Test pilot Col. Doug Benjamin quipped that even the clock on the cockpit was purchased at a store, and the cabin air system was equivalent to a hairdryer.
The Bird of Prey, to appear, was plucked from science fiction. Tailless and possessing gull wings, it was 47 feet long and 23 feet wide, and derived its nickname from the Star Trek Klingon Bird of Prey. All detail—smooth surfaces and absence of vertical stabilizers, down to buried engine—was specifically designed to reduce radar and infrared signatures. Even the color pattern of the paint was chosen to aid the camouflage of the plane against daylight skies.
Despite replacing traditional fly-by-wire controls with more straight-forward manual hydraulics, the Bird of Prey flew wonderfully stable. Aerodynamics were so precisely fitted that it flew effortlessly in flight, showcasing speed and altitude weren’t its primary goals. Its sole Pratt & Whitney JT15D-5C engine took it to approximately 300 miles per hour and offered a service ceiling of 20,000 feet, enough to test stealth performance as well as manufacturing processes.
The Bird of Prey made its initial flight on September 11, 1996. It flew 39 flights in the next three years, sorting out problems like drag caused by the landing gear. On the final flight in 1999, the program had managed to demonstrate that stealth planes could be designed quickly, cheaply, and safely.
Even though never deployed on active duty, the heritage of the Bird of Prey cannot be dismissed. Design repercussions had a direct impact upon Boeing’s X-45 Unmanned Combat Air Vehicle and helped shape tailless, stealth-centered design paradigms adopted in the F-22 Raptor, F-35 Lightning II, and even the B-21 Raider. Boeing executive Jim Albaugh epitomized its influence succinctly: “We changed the rules on how to design and build an aircraft.”
Today, only a single Bird of Prey ever built towers over an F-22 Raptor in the Modern Flight Gallery at the National Museum of the U.S. Air Force in Dayton, Ohio. The cockpit remains out of reach of the public, a silent nod to the aircraft’s clandestine origins.
Even though it never carried weapons, dropped bombs, or hit the headlines like other better-known relatives, the Bird of Prey played a critical behind-the-scenes part in setting the direction of stealth airpower. Its legacy is proof that sometimes the most revolutionary planes are not designed to win conflicts—those are designed to transform them.
