XV-4 Hummingbird

infobox Aircraft
name = XV-4 Hummingbird
type = VTOL
manufacturer = Lockheed



caption = First prototype XV-4 Hummingbird
designer =
first flight = 7 July 1962
introduced =
retired =
produced =
number built = 2
status = Retired
unit cost =
primary user = United States Army
more users =
developed from =
variants with their own articles =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 and drawing on the lessons of the Hummingbird.

None of the early American V/STOL designs would result in a production plane. 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.

pecifications (first prototype)

aircraft specifications
plane or copter?=plane
jet or prop?=jet

crew=
capacity=
length main= 32 ft
length alt= 10.3 m
span main= 26 ft
span alt= 7.9 m
height main= 11 ft 8 in
height alt= 3.58 m
area main=
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loaded weight main= 11,607 lb
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engine (jet)=Pratt & Whitney JT12A
type of jet= turbojets
number of jets=2
thrust main= 3,300 lbf
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max speed main=336 mph
max speed alt= 541km/h
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never exceed speed alt=
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ee also

aircontent

related=

similar aircraft=
* XV-5 Vertifan
* XFV-12
* Hawker P.1127

lists=
* List of military aircraft of the United States
* List of Lockheed aircraft
* List of VTOL aircraft

see also=

References

* X-Planes and Prototypes by Jim Winchester
* [http://avia.russian.ee/air/usa/lok_hummingbird.html Lockheed VZ-10 Hummingbird/XV-4]
* [http://www.vstol.org/wheel/VSTOLWheel/LockheedXV-4A.htm VSTOL.org Wheel]