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XV-4 Hummingbird: Wikis


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XV-4 Hummingbird
First prototype XV-4 Hummingbird
Manufacturer Lockheed
First flight 7 July 1962
Status Retired
Primary user United States Army
Number built 2

The Lockheed XV-4 Hummingbird (originally designated VZ-10) was a U.S. Army project in the 1960s, one of many attempts to produce a V/STOL vertical take off / landing jet. At a design speed of 336 mph, the Hummingbird was slower than some propeller-powered transports.

The design used doors at the top and bottom of the fuselage intended to augment thrust ejected into this area with cold air. In theory, a 11,607 lb aircraft could be lifted by a 6,600 lbf engine. Unfortunately, performance was far below the estimates only 1.04 thrust-to-weight in practice and the prototype crashed on 10 June 1964, killing the pilot. The second aircraft was converted to lift jets instead, also crashing after several tests.

Rockwell's XFV-12 would be even less successful at venting cold air to augment thrust through the wings. The Lockheed F-35 Joint Strike Fighter would later employ a shaft-driven lift fan, also located in the fuselage.

None of the early American V/STOL designs would result in a production aircraft. The British Hawker Siddeley Harrier used vectoring nozzles, while the Russian Yakovlev Yak-38 Forger attack jet used lift jets in conjunction with rotating rear nozzles.


Specifications (first prototype)

General characteristics


See also

Comparable aircraft

Related lists



  • X-Planes and Prototypes by Jim Winchester

External links



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