YF-118G: Why Boeing’s Futuristic ‘Bird of Prey’ Stealth Fighter Never Entered Service

The YF-118G is a little-known aircraft, but it was one of the pioneers in stealth technology that inspired the construction of iconic aircraft such as the F-22.
USAF Museum

The YF-118G “Bird of Prey” was one of the most important experimental aircraft of the ’90s. It showed a very innovative design and new technologies that would later be used in the fifth-generation aircraft flying today.

This plane never went into mass production, but its legacy can now be seen reflected in the F-22, which wouldn’t have existed without the technology of this very distinctive aircraft.

The groundbreaking YF-118G

The YF-118G “Bird of Prey” was developed in secret by a team of engineers and scientists from McDonnell Douglas and Boeing. 


The aircraft first flew in 1996 and was revealed to the public in 1997. It was designed to be the next generation of stealth fighters, incorporating the latest in stealth technology. 

This made it a very advanced aircraft equipped with state-of-the-art avionics and sensor suites that rendered it unique and innovative.

A highly innovative design

National Museum of the USAF
National Museum of the USAF by loganrickert. Licensed under CC by 2.0

The YF-118G was a radical design that broke all the rules. The “Bird of Prey” was designed to be highly maneuverable and very difficult to track on radar.


To achieve this, the entire airframe was shaped to minimize the reflection of radar waves. The engines were buried deep inside the fuselage to reduce the radar signature further. The aircraft was virtually invisible to radar, having a radar cross-section of a small bird.

It was also designed to be incredibly maneuverable. The wings were sweeping and canted at a sharp angle. The horizontal stabilizers were mounted on top of the vertical stabilizers. This allowed the plane to make extremely tight turns without losing lift.

The YF-118G was so agile that it could outmaneuver even the most agile fighters, but the project was canceled anyway. In any case, the technology developed for the “Bird of Prey” laid the foundation for future stealth aircraft like the F-22 Raptor and B-2 Spirit.


F-22 Raptor AF 10192 192nd Fighter Wing
F-22 Raptor AF 10192 192nd Fighter Wing by Tomás Del Coro. Licensed under CC by 2.0

 YF-118G and F-22 Raptor

YF-118G Boeing Bird Of Prey
Boeing Bird Of Prey by Valder137. Licensed under CC by 2.0

It’s clear that the stealthy YF-118G remains a lesser-known name compared to the F-22. However, it pioneered several innovations because it allowed the creation of the F-22.

This exotic aircraft’s most long-lasting legacy contribution was its airframe and stealth capabilities at an affordable price. Actually, it was much cheaper to produce than current fifth-generation aircraft.

Now, the only YF-118G Bird of Prey ever produced is on display at the National Museum of the U.S. Air Force, Wright-Patterson Air Force Base, located just above the F-22 Raptor as a reminder of where the F-22 technology comes from.


YF-118G specs

  • First flight: 1996
  • Retired: 1999
  • Number built: 1
  • Crew: 1
  • Length: 46 feet 8 inches (14.22 meters)
  • Wingspan: 22 feet 8 inches (6.91 meters)
  • Height: 9 feet 3 inches (2.82 meters)
  • Max takeoff weight: 7,400 pounds (3,356 kilograms)
  • Maximum speed: 299 mph (482 km/h)
  • Service ceiling: 20,000 feet (6,100 meters)

Despite its impressive capabilities, the YF-118G was ultimately never put into production, partly due to the high cost of developing and maintaining such an advanced aircraft.

Nevertheless, the Bird of Prey remains one of the most visually fascinating military aircraft ever developed.

This experimental aircraft is the father of the fighter jets and stealth bombers we know today

Little is known about the true purpose for which it was developed. It was probably never intended to be mass-produced.


In any case, its technology definitely paved the way for a new generation of aircraft that are now the flagship projects of U.S. military aviation with stealth capabilities.

Featured image credit: Boeing Bird of Prey USAF by USAF Museum. Public Domain.

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