Sources tell us that this mysterious plane, officially called the Bird of Prey, will soon be declassified. But for now, not much is known about the aircraft except that it uses a unique swing-wing mechanism to play a variety of military roles.

As far back as 1989, aviation aficionados began hearing rumors that the Pentagon was developing a new aircraft to replace its aging fleet of swing-wing F-111s, which retired permanently in 1995. The F-111 was a medium-size bomber capable of defending itself as a fighter and then speeding away from enemies at more than 1,600 miles per hour.

A few years later, reports surfaced of a new swing-wing aircraft sighted near Cannon Air Force Base in New Mexico, and at Langley Air Force Base in Virginia. High ranking officials are said to have gathered in secure hangars at the two air bases for a sneak peek at the new aircraft. It was also observed circling high over Amarillo, Texas. POPULAR SCIENCE investigated the reports for an exclusive story on the Bird of Prey in 1995.

Since then, we have learned that the aircraft is not a standard swing wing plane as first reported, but instead employs a unique forward sweeping wing apparatus. Because the wing pivots like a blade folding into the handle of a pocketknife, pilots have nicknamed the aircraft Switchblade. The clever design makes the aircraft versatile enough to serve as both a fighter and bomber.

Switchblade’s wings are attached to the aircraft’s fuselage at a pivot point toward the rear of the plane. When the wings are fully extended, the aircraft can slow to drop precision weapons or to land on short, unimproved runways. With the wings swept farther forward, the aircraft becomes a highly agile combat platform. And when the wings are swept fully forward, with the trailing edge transformed into a leading edge, the aircraft assumes a delta shape perfect for dashing away at speeds up to Mach 3.

Drawings and a description of just such a pivoting wing appear in U.S. Patent 5,984,231, which states that “the aforementioned apparatus may be used in a method to configure the aircraft for flight in a desired flight regime. This method includes moving the wing to an optimal position for the desired flight regime.” In other words, the Switchblade plane can take on multiple missions simply by reconfiguring itself in midflight.

Northrop Grumman Corp., a longtime builder of secret aircraft based in Los Angeles, filed the patent in November 1999. Declassification usually follows within a year of such a patent filing.

Switchblade builds on earlier work that was done by both Northrop and the Grumman Aircraft Corp., which merged in 1994. Previously, Grumman was responsible for the development of the X-29, an experimental fighter-size aircraft with forward-swept wings. The wings made the X-29 look as though it was flying backward, but they also made the aircraft exceptionally maneuverable and resistant to stalls—even at attack angles as high as 45 degrees.

An aircraft with forward-swept wings is inherently unstable, which is what makes it so agile. But for an attack aircraft, this wing configuration has some major drawbacks. Foremost among them: The platform is not stable enough for pin point bombing.

Engineers realized, however, that an aircraft designed to go from a stable configuration to an unstable one at the flick of a switch would be a very versatile tactical attacker. If it could also be made stealthy, and given the ability to fly at speeds of Mach 3 or higher, it would be a military planner’s dream come true.

Officially, the Air Force does not have a replacement for the F-111. But never before has the Air Force abandoned an aircraft mission type, such as that of the medium bomber. Currently, the Air Force has three heavy bombers (the B-1B, B2, and B-52) and one small bomber (the F-1117A, which can only carry two conventional bombs), unless the F-15E is included (it’s a 1970s-era fighter adapted to fill a tactical bombing role). There is no white-world, or non-secret, aircraft that comes close to duplicating the versatility and medium-size bomb load of the retired F-111 Aardvark.

Any F-111 aircraft follow-on would have to meet all the future tactical needs of the U.S. armed forces—including precision weapons delivery, air combat superiority, long range, low radar signature, and high-speed ingress and egress from the target area. To design an aircraft that is all things to all people is a considerable challenge. One aviation engineer likens it to “building an lndy racer that can climb rocky hills, haul 2 tons of cargo, and still outrace all the police cars sent to chase it.”

Multi-mission aircraft of the past have invariably had to make design sacrifices in one area or another, never really cutting it as a flying Swiss Army knife. But now the Switchblade does appear to meet all the design criteria for an advanced multi-regime tactical bomber/fighter.

Both Northrop and Grumman have considerable expertise in designing advanced aircraft. Northrop was, the chief contractor on the B-2 stealth bomber, the YF-23 advanced tactical fighter prototype, and the recently declassified Tacit Blue. Grumman designed and built both the X-29 and the Navy’s premier variable-swept winged aircraft, the F-14 Tomcat.

In hindsight, since the two companies are now one, a merger of their design strengths in one aircraft may have been inevitable. Could both the YF-23 and the X-29 have been white world covers for a black-world project, rather than dead ends? Together they may have yielded a military aircraft of exceptional capabilities.

If so, a new covert squadron would have been formed to fly these aircraft. Recently POPULAR SCIENCE obtained from aviation author and historian Jim Goodall a squadron patch believed to be worn by pilots who fly the Bird of Prey. As with many such patches, this one contains a clue about the aircraft: The sword and its forward-swept hilt may be a stylized bird’s-eye view of the aircraft.

Rumbles from inside the Pentagon indicate the aircraft is now undergoing declassification review. Like the super-secret F-117 before it, Switchblade may one day fly above us in broad daylight or become the darling of military air shows, but until then it flies only at night, and the details of its design are known only to the inner circle of the black world.