The Bird of Prey was a black project aircraft, intended to demonstrate stealth technology, developed by McDonnell Douglas. Funded by the company at a price of $67 million, it was a very cost-effective program (compared to many other programs of similar scale), developing technology and materials which would later be used on Boeing’s X-45 UCAV. As an internal project, this aircraft was not given an X-plane designation.
Because it was a demonstration aircraft, the Bird of Prey used a commercial off-the-shelf turbofan engine and manual hydraulic controls rather than fly-by-wire. This shortened the development time and reduced the cost significantly (a production aircraft would have computerized controls).
The shape is aerodynamically stable enough to be flown without computer correction, a characteristic not found in other modern fighters or stealth planes, such as the F-16 or the F-117. Its aerodynamic stability is due to the same mechanisms found in canard aircraft such as the VariEze, the lift normally generated by the canards being provided by the chines (which therefore keeps the nose from sinking). This configuration, which can be stable without a horizontal tailplane and a conventional vertical rudder, is now a standard in modern stealth UAVs such as the X-45 and X-47, tailless aircraft which use drag rudders (asymmetrically-used wingtip airbrakes) for rudder control.