While the Harrier and the Yak-38 Forger are two of the first Vertical or Short Take-Off and Landing, or V/STOL, aircraft used for combat, there were many earlier attempts at making similar capabilities work. The United States Army was responsible for one such attempt.
The Army has operated fixed-wing aircraft before, like the Caribou and Sherpa, but the XV-5 Vertifan was particularly interesting. It first flew in 1967, just shy of two decades after the Key West Agreement delineated which armed services were to develop and operate certain capabilities. The Vertifan was a fixed-wing aircraft, which was largely the purvue of the nascent U.S. Air Force. But this wasn't the only thing that made it so intriguing.
The XV-5A never really got past the prototype stage. (US Army photo)
The XV-5 Vertifan was intended to test out a lift-fan arrangement. Three fans were installed in the wings to provide lift, while the plane would fly using a pair of J85 engines, similar to those used in Northrop F-5 fighters. The plane had a crew of two, was capable of a top speed of 550 miles per hour, and could fly 1,000 miles unrefueled. By comparison, the AV-8B Harrier currently in service has a top speed of 665 miles per hour and a maximum range of 1,367 miles per hour.
Two XV-5s took flight, but the plane never got past the testbed stage. For one thing, the fans just didn't provide the thrust the Army was hoping for. Furthermore, despite the use of cross-ducting – which successfully improved safety – both prototypes crashed, killing one of the test pilots.
One prototype was rebuilt as the XV-5B after a crash that killed its pilot. (NASA photo)
The XV-5 proved to be unsuited for operational service, but the lift-fan concept was validated — in fact, today's F-35B, the V/STOL version of the Joint Strike Fighter, uses a lift-fan.
Learn more about this Army "jump jet" in the video below!