The single-seat, stealth technology demonstrator that would be viewed as the model for stealth techniques development and aircraft design methodologies was the Boeing Bird of Prey. Running secretly from 1992 to 1999, the maiden flight of the project came in the fall of 1996. Named for the Klingon spacecraft from Star Trek, the Bird of Prey was an exponent of innovative aerospace engineering.
Over its 38 test flights, the Bird of Prey explored ways to minimize signature for both the unaided person and radar. It also served to prove new methods of design and production like large, single-piece composite structures, design and build by virtual reality technique, and even disposable tooling. These made it a standard practice and affected other Boeing projects like the X-32 Joint Strike Fighter, and the X-45A Unmanned Combat Air Vehicle.
For this to be achieved, the Bird of Prey made use of advanced stealth concepts, like “gapless” control surfaces which invisibly into the wings for minimum radar “cross-section,” and a front view of the engine intake was designed to hide it from radar. However novel the active design might have been, some off-the-shelf technologies were used in the aircraft to keep down costs and speed up construction. Its control system was fully manual, with no computer assists, and the landing gear was borrowed from Beech King Air and Queen Airplanes.
The engine for the aircraft was a Pratt & Whitney JT15D-5C turbofan engine, producing 3,190 pounds of thrust. The aircraft had a top speed of 300 mph at an altitude of up to 20,000 feet. Although relatively humble in its performance figures, the priority in the aircraft was its stealth design, rather than a high degree of aerodynamic performance.
The program was a success, and it is stated that Boeing donated the same to the National Museum of the United States Air Force, located in Dayton, Ohio, United States in 2002. The same resulted after the declassification of the program that opened up the large contribution made by the meant aircraft towards stealth technology and aircraft design.
After the USAF rejected McDonnell Douglas, now part of the Boeing Corporation, in its attempts to get contracts for new tactical military jets, the company initiated the Bird of Prey program in response. Initiated after the sting of such losses as the new Advanced Tactical Fighter program, the YF-23 competition to the F-22, this effort tacitly refocused on stealth and affordability. Out of it came the Bird of Prey, formally the YF-118G, featuring striking design elements that helped crush radar cross-section and minimize its infrared signature.
The Bird of Prey program was remarkable regarding economical quantities since it took a reputed total of $67 million to develop the project, equivalent to less than two new 737s at that time. All these methods ensured rapid prototyping, computer simulation, and the use of existing parts. The possibility of designing and assembling the aircraft became simplified, which further allowed the ease as well as the cost of fabricating the tools.
Despite its odd shape and primitive systems, Bird of Prey proved a great test bed for stealth technology. It showed that Boeing could manufacture stealth aircraft and helped to advance numerous technologies for rapid prototyping and composite material construction.
The case is far from the test flights of the Bird of Prey and delves into the innovative techniques deployed in the design and production of the subsequent stealth aircraft, like the X-32 and X-45A. Although the Bird of Prey never entered actual service, its influence on stealth technology and the design of aircraft echoes through the halls of today’s aerospace engineering.
Today the Bird of Prey stands as a testament to engineering insight and determination during development. The undisputable influence of stealth technologies and aircraft designs is a significant part of the domain of military aviation history.