Summary and Key Points: Expert Steve Balestrieri profiles the YF-118G Bird of Prey, the McDonnell Douglas Phantom Works stealth demonstrator Boeing built at Area 51 between 1992 and 1999 with $67 million of its own money. Named for the Klingon ship, it used Beech King Air landing gear, a Harrier ejection seat, a Pratt & Whitney JT15D-5C turbofan, a single-piece composite body, and disposable tooling; it cruised at 300 mph and flew 38 times before the Pentagon revealed it in 2002.
The YF-118G Bird of Prey Was Amazing
The YF-118G “Bird of Prey” was arguably one of the most unique, best-looking aircraft ever built. If you think it resembled a sci-fi spacecraft from Hollywood, you’d be right.
The aircraft was named after the Klingon Bird of Prey from the Star Trek franchise because its outward appearance mimicked the Star Trek spacecraft. The aircraft minimized radar cross-section with its blended-wing-body configuration, shielded engine intake, and “gapless” control surfaces.
McDonald Douglas’ Phantom Works designed the Bird of Prey, which Boeing built in the 1990s. This aircraft was developed at Area 51.
What Was The Purpose of the Cheap Stealth Aircraft?
The YF-118G Bird of Prey was a highly strategic private-venture technology demonstrator developed by McDonnell Douglas (later Boeing) Phantom Works between 1992 and 1999.
Its primary purpose was to pioneer rapid, low-cost manufacturing and design techniques for future stealth aircraft, rather than to serve as an operational fighter.
It was never intended for operational service, but to test the limits of stealth technology at a low cost. Boeing transitioned from a paper design to building the aircraft using off-the-shelf parts for less than $67 million. That’s less than the cost of a single F-35 stealth fighter. The program was a huge success, and the lessons learned paved the way for future stealth aircraft, such as the X-32, the F-22, and the F-35, as well as the X-45 unmanned combat drone, which forever changed aircraft design.
YF-118G. Image taken by Harry J. Kazianis for 19FortyFive.
YF-118G. Image taken by Harry J. Kazianis for 19FortyFive.
Why did Boeing fund this project with approximately $67 million of its own money?
Boeing wanted to prove that it could design and build an advanced, all-aspect stealth aircraft at a fraction of the cost of traditional programs like the B-2 Spirit. To achieve this, they utilized rapid prototyping. The team used “virtual reality” computer-aided design to speed up development.
Unique Blend of Spare Parts:
In an incredible display of resourcefulness and frugality, Boeing saved a boatload of money by building the Bird of Prey from spare parts.
To speed development and cut costs, the aircraft used existing, non-specialized components.
Examples include landing gear adapted from a Beech King Air and Queen Air; a single commercial Pratt & Whitney JT15D-5C turbofan engine; an ejection seat from a Harrier; and cockpit controls from various existing tactical aircraft.
One test pilot even joked that the clock was from a retail store.
The Bird Of Prey Was A Game Changer:
The Boeing YF-118G Bird of Prey was a revolutionary experimental aircraft developed to explore and refine stealth technology.
This single prototype showed that Boeing could rapidly move an effective stealth platform into the prototyping phase, helping the United States and NATO maintain a qualitative technical edge over peer and near-peer adversaries.
This unique aircraft’s most significant contribution to America’s defense apparatus was its boldness and success.
The body was built from a single piece of composite material, eliminating the ridges and seams of traditional aircraft that create radar reflections.
The Engine Was Small:
The Bird of Prey was powered by a Pratt & Whitney JT15D-5C engine; it was far from a performance giant in speed or altitude. Its cruising speed was just 300 miles per hour; the stealthy aircraft was slower than a C-130 Hercules, and its maximum operational ceiling was 20,000 feet. But the designers weren’t looking for a hot rod; they wanted near invisibility on radar.
When the United States began producing the F-117 Nighthawk in 1983, it was far slower than the fighters of the day. But the Nighthawk wasn’t a fighter; it was a nearly invisible attack aircraft.
F-117 Stealth Fighter. Image Credit: US Government.
An F-117 Nighthawk taxies down the runway after landing Jan. 11 at Kunsan Air Base, Republic of Korea. A squadron of F-117s, together with 300 Airmen, have deployed here in support of a continuing force posture adjustment throughout the Pacific. The aircraft, assigned to the 9th Expeditionary Fighter Squadron, is part of the third squadron of Kunsan AB’s host unit, the 8th Fighter Wing, during the deployment’s duration. (U.S. Air Force photo/Senior Airman Darnell Cannady)
US-made F-15s and F-16s had a radar cross-section of 82 square feet; the F-117 carried one of only slightly more than a tenth of an inch (0.11 inches).
The radar cross-section (RCS) was estimated to be as small as a mosquito. Engineers also placed the powerplant deep within the fuselage to minimize its infrared signature. They carefully designed the paint shading to visually mask the fuselage’s actual shape in daylight.
How Boeing Kept It Under Wraps:
The Bird of Prey was a further development of stealth technology for future designs. But because it was based at the secret US site known as Area 51, the program was well suited to keeping the aircraft’s development secret.
The Air Force ran the program in complete secrecy from 1992 to 1999, with the first flight taking place in 1996. The Pentagon acknowledged the Bird of Prey in 2002, but only after incorporating much of its stealth technology into other aircraft, such as the X-32 Joint Strike Fighter (the future F-35) and the X-45A Unmanned Combat Air Vehicle.
The aircraft made only 38 test flights between 1996 and 1999, limiting the opportunities to observe it. But the company did a great job of keeping the aircraft’s secrecy under wraps.
“In its 38 flights, the Bird of Prey tested ways to make aircraft less observable to the eye and to radar,” the U.S. Air Force said. “It also validated new ways to design and build aircraft using large single-piece composite structures, “virtual reality,” computerized design and assembly, and disposable tooling.
Stealthy Airframe and Spare Parts:
Ultimately, the entire program reportedly cost $67 million, less than two new 737s at the time.
The Boeing design team used single-piece composite structures and disposable tooling. In the final specification, the aircraft measured 47 feet long, with a 23-foot wingspan and a curb weight of about 7,400 pounds.
After the Bird of Prey completed 38 test flights between 1996 and 1999, the program was successful enough to survive Boeing’s 1997 acquisition of McDonnell Douglas.
The program was publicly unveiled in late 2002, and the National Museum of the United States Air Force in Dayton, Ohio, received the aircraft, where it remains on display today. We took many photos of the YF-118G at that museum.
YF-118G. Image taken by Harry J. Kazianis for 19FortyFive.
Fun fact: the YF-118G is suspended right above the F-22 at that very museum.
About the Author: Steve Balestrieri
Steve Balestrieri is a National Security Columnist. He served as a US Army Special Forces NCO and Warrant Officer. In addition to writing on defense, he covers the NFL for PatsFans.com and is a member of the Pro Football Writers of America (PFWA). His work was regularly featured in many military publications.