We all think of “American stealth aircraft,” and first the F-117 Nighthawk, B-2 Spirit, and F-22 Raptor come to mind. But tucked away in the wings of history is a lesser-known airplane that never fought a war but left an indelible mark—the Boeing YF-118G, colloquially called the “Bird of Prey.”
Conceived in secret during the 1990s at the super-secret Groom Lake testing facility, the Bird of Prey was never meant to see combat. Instead, its purpose was more sinister but no less vital: to experiment and refine cutting-edge stealth technology and low-cost production methods—lessons which would later go on to shape an entire new family of combat planes.
Timing was also important for McDonnell Douglas. Having missed with high-profile Pentagon bids such as the Advanced Tactical Fighter program, the company needed a vehicle with which to demonstrate that it still had what it took to be innovative. Phantom Works, the research and development arm of the company, stepped up to the challenge in 1992, determined to come up with something both innovative and practical.
Stealth mastermind Alan Wiechman, a veteran of the F-117 program in earlier years, led the program. Under his leadership, US stealth technology remained far ahead of any conceivable competitors.
What is even more amazing about the Bird of Prey is that it was designed on a shoestring budget: a measly $67 million—a trifle compared to the usual government-subsidized aircraft programs. Engineers employed rapid prototyping, computer simulation, and creative recycling of recycled parts: the engine came from a corporate aircraft, the ejection seat from a Harrier jet, and the cockpit controls from retired fighter jets. Even test pilot Col. Doug Benjamin joked that the cockpit clock was purchased at a store, and the air system was the equivalent of a hairdryer.
The plane itself resembled something out of science fiction. It was tailless and had gull-shaped wings, 47 feet in length and 23 feet in width. Its origin was from the Klingon Bird of Prey from Star Trek. It was everything about it—sleek surfaces and no vertical stabilizers, a hidden engine—that was intended to make it less visible to radar and infrared. Even its camouflage color scheme was chosen to match daylight skies.
Despite the use of less sophisticated manual hydraulics rather than hi-tech fly-by-wire, the Bird of Prey handled like a dream in flight. Speed and altitude were not the main goals; stability and stealth performance were. Powered by a single Pratt & Whitney JT15D-5C engine, it was able to take off at about 300 miles per hour and climb to 20,000 feet—high enough to test flight dynamics and production ideas.
It made its first flight on September 11, 1996. In the subsequent three years, the aircraft made 39 flights, resolving trivial problems such as drag caused by the landing gear. Through the conclusion of the program in 1999, it proved that stealth planes could be readily designed and rapidly developed safely and effectively.
Even though it was never placed in active duty, the Bird of Prey established a legacy. It influenced Boeing’s X-45 Unmanned Combat Air Vehicle and established the trend for tailless, stealth-oriented design methods employed on the F-22 Raptor, F-35 Lightning II, and B-21 Raider. Boeing official Jim Albaugh put it best: “We changed the rules on how to design and build an aircraft.”
Today, the sole Bird of Prey ever constructed hangs over an F-22 Raptor at Dayton’s Modern Flight Gallery in the National Museum of the U.S. Air Force. The cockpit is still off-limits, a discreet reminder of the secretive nature of the aircraft.
Though it never bore guns or made the front pages like its illustrious cousins, the Bird of Prey secretly played a role in shaping the future of stealth flight. Its story is a reminder that the most innovative airplanes aren’t always intended to fight wars—though often, they are built to transform the way wars are fought.