In 1959, with a success of British "vectored jets" VTOL aircraft Hawker P.1127, Lockheed set up a privately funded VTOL design that was approached in a different way, the augmented lift-jets. It was the mixing hot engine exhaust gas with cold air to increase an engine thrust. Lockheed made and tested their Model 330 Hummingbird that the exhaust from the jet engine was directed to the piping nozzles where installed within the fuselage downward. The fuselage bulk was occupied as the mixing chamber with cold air intake from upper hatch. Lockheed proposed this study to U.S. Army and was awarded a contract for two prototypes, designated XV-4A in competition with Ryan XV-5A and Hawker XV-6A in 1961. The first conventional flight was on July 1962. Three month later, first hover was tested but the actual thrust augmentation was much less than expected. The first XV-4A was crashed in 1964. The second XV-4A then was modified as XV-4B for flight research by USAF until crashed in 1969.

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Experimental VTOL close-support fighter

To research augmented lift-jet VTOL configuration 

25ft.8in.

32ft.8in.

11ft.9in.

2x Pratt & Whitney JT12A turbojet

515 mph

2

Not installed

The Lockheed XV-4A Hummingbird is suitable to group with the following collection series.

U.S. Tri-services V/STOL experimental aircarft

McDonnell XV-1 (XH-35) Convertiplane

Sikorsky XV-2 (XH-36)

Bell XV-3 (XH-33) Convertiplane

Lockheed XV-4A Hummingbird

Ryan XV-5A Vertifan

Hawker Siddeley XV-6A Kestrel

De Havilland CV-7 Buffalo

McDonnell Douglas/British Aerospace AV-8A Harrier

Hughes XV-9A Hot Cycle

Rockwell International OV-10A Bronco

M.S.U. XV-11 Marvel

Rockwell International XFV-12

Bell XV-14A (redesignated to XV-15A)

Bell XV-15A Tiltrotor

McDonnell Douglas/Hawker Siddeley XV-16 Super Harrier

DeHavilland UV-18A Twin Otter

NavAir V-19A (cancelled)

Pilatus UV-20A Chiricahua

U.S. Navy's PV-21 Patrol Airship concept (cancelled)

Bell V-22 Osprey

Skytrader UV-23A

U.S. Army V/STOL experimental aircarft

Hiller VZ-1 Pawnee

Vertol VZ-2

Ryan VZ-3 Vertiplane

Doak VZ-4D

Fairchild VZ-5

Chrysler VZ-6

Curtiss-Wright VZ-7AP Aerial Jeep

Piasecki VZ-8P Airgeep

Avro VZ-9 Avrocar

Lockheed VZ-10 (XV-4A) Hummingbird

Ryan VZ-11 (XV-5A) Vertifan

Hawker Siddeley VZ-12 (XV-6A) Kestrel

Post war U.S. experimental aircraft

1960s VTOL fighter respond to Hawker Kestrel

Hawker Kestrel - U.K.

Lockheed XV-4A Hummingbird - U.S.A.

VFW-Fokker VAK-191 - German

Yakovlev Yak-36 Freehand - U.S.S.R.