Bird Of Prey
The Bird of Prey project formally started in 1992. The US$67 million development cost was provided by McDonnell Douglas (acquired by Boeing in 1998), but the USAF agreed to provide flight-test facilities and security, including chase aircraft and access to a secure flight-test center.
Though its primary mission was to demonstrate stealth technology, it also allowed Boeing's Phantom Works the company's special-projects arm to demonstrate it could build prototype airplanes quickly and cheaply. The airplane was made from a small number of carbon fiber composite parts, and - amazingly, in view of its shape, - had a simple all-manual flight control system without a computer in sight.
The Bird of Prey has made 38 flights since being secretly launched in 1996.
"Here we have an example of a classic 'black' programme: an aircraft which has been built and flight tested for a number of years - and no one outside the programme knew about it," says Nick Cook, aerospace consultant to Janes Defence Weekly.
Sources suggest they may include active camouflage systems to reduce visibility by using panels or coatings that change colour or luminosity. This could allow safe combat missions in daylight, rather than being restricted to night flying. "And that would represent a revolutionary milestone in aerial warfare," says Cook.
The once highly classified project ran from 1992 through 1999, and was revealed because the technologies and capabilities developed have become industry standards, and it is no longer necessary to conceal the aircraft's existence.
Boeing pilot Joe Felock made it clear that the Bird of Prey named after a Klingon spacecraft from Star Trek was a low-performance demonstrator, designed to put a representative shape into the air with minimum time and expense.
Maximum speed was 260kt and the highest altitude achieved was 20,000ft. The 14.2kN Pratt & Whitney Canada JT15D-5 engine would have been working hard to propel a small-winged 3,360kg aircraft even if it were not breathing through a tortuous inlet; Northrop Grumman, using the same engine on its X-47A Pegasus unmanned combat air vehicle (UCAV) demonstrator, has reported problems in reducing duct losses.
It has not been confirmed whether the Bird of Prey was ultimately intended to be manned or unmanned. But the aircraft has clearly had a major influence in the design of Boeing's unmanned combat air vehicle (UCAV) demonstrator, the X-45. Two of these pilotless combat planes are currently undergoing test flights.
Armed UCAVs are among the hottest projects in military aviation, having the obvious advantage of not risking life, as well as being cheaper than manned aircraft.