The realm of stealth aircraft ultimately required dedicated technology demonstrators to prove various qualities sound or unsound. Boeing and McDonnell Douglas teamed to produce such a vehicle in their private venture "Bird of Prey" - a single-seat, single-engine demonstrator intended solely for furthering other projects - namely the X-32 Joint Strike Fighter (JSF) and X-45 Unmanned Combat Air Vehicle (UCAV) which were to arrive later. Only one Bird of Prey was ever completed and this product achieved its first flight on September 11th, 1996. It served up until retirement in April of 1999, completing a total of 38 total flights providing critical data.
As with Lockheed's "Skunkworks" secret programs label, McDonnell Douglas adopted the "Phantom Works" name to cover projects deemed "off the beaten path". This led to the Bird of Prey never receiving a formal "X" designation throughout its testing life. The aircraft entered development during 1992 and was available for flight testing as soon as 1996. In 1997, with the merger of defensive powerhouses McDonnell and Boeing, the Phantom Works section fell under the parent company name of Boeing where it resides today (2015).
Much of the development speed of the Bird of Prey initiative was largely due to the use of existing components to rapidly produce a working, flyable form. This led to the readily available Pratt & Whitney Canada JT15D-5C turbofan of 3,190 lb thrust as the powerplant of choice. Instead of the more complex and expensive Fly-By-Wire (FBW) digitally-assisted control scheme found on many modern aircraft, the Bird of Prey was outfitted with a manual hydraulic scheme. The finalized form of the aircraft was very futuristic for its time - a diamond-like shape adopted with a forward-set cockpit (the pilot under a large tinted canopy), downward-cranked wing mainplanes and a dorsal-mounted intake. A tricycle undercarriage (taken from a Beech King Air and Queen Air series aircraft) was fitted. The aircraft lacked more traditional features like true vertical tail surfaces and horizontal tailplanes though a single ventral plane was noted under the engine exhaust section. Dimensions of the airframe included a length of 47 feet and a wingspan of 23 feet with a weight of 7,4000 lb.
In testing, the air vehicle was used to test all manner of low-observable qualities. Its intake opening was more akin to a slit and shielded from the front by the bulbous cockpit. Its engine exhaust area was shielded and control surfaces on the wings were contoured to fit their parent shape. One additional quality test reportedly undertaken was "active camouflaging" in which the special skin of the aircraft could mimic its surrounding terrain, making it more difficult to spot with the naked eye. The success of failure of this phase is unknown.
Since performance was never a key consideration of the program, the Bird of Prey held a maximum speed of just 300 miles per hour and a service ceiling up to 20,000 feet.
Once its useful testing days were over, the sole Bird of Prey vehicle was handed to the National Museum of the United States Air Force in Dayton, Ohio during mid-2003 for display where it remains today (2015). Its name "Bird of Prey" was an homage to the enemy spacecraft featured in the motion picture "Star Trek II: The Wrath of Kahn" - the McDonnell / Boeing product's shape generally resembling that of the Klingon warship.