Lockheed XV-4 Hummingbird

XV-4 Hummingbird

First prototype XV-4 Hummingbird
Role	VTOL
Manufacturer	Lockheed
First flight	7 July 1962
Status	Both aircraft destroyed during testing
Primary user	United States Army
Number built	2

The Lockheed XV-4 Hummingbird (originally designated VZ-10) was a U.S. Army project to demonstrate the feasibility of using VTOL for a surveillance aircraft carrying target-acquisition and sensory equipment.^[1] It was designed and built by the Lockheed Corporation in the 1960s, one of many attempts to produce a V/STOL vertical take off/landing jet. Both prototype aircraft were destroyed in accidents.

Design and development

Vertical take-off lift was obtained by exhausting the engine flow downward through multiple nozzles. The nozzle thrust was augmented by a secondary flow of cold air.^[1] 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 producing lift by using engine exhaust to entrain cold air, in this case through flaps on the wings. The Lockheed F-35 Joint Strike Fighter would later employ a shaft-driven lift fan 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.

Testing

The first conventional takeoff flight of the first prototype, XV-4A (62–4503), took place on 7 July 1962. Initial tethered flight tests were carried out on 30 November 1962 with the first free hovering flight occurring on 24 May 1963. The first flight to transition from hovering to forward flight took place on 8 November 1963. 62–4503 was destroyed in a fatal crash in Cobb County on 10 June 1964.

Lockheed modified the second prototype aircraft between 1966 and 1968 to XV-4B standard. The two Pratt & Whitney JT12 engines were replaced with six General Electric J85 turbojets four of these units acting as lift jets. This aircraft crashed in Georgia on 14 March 1969, the pilot, Harlan J. Quamme, escaped uninjured by use of the ejection seat.

Specifications (XV-4A)

Data from Lockheed Aircraft since 1913^[2]

General characteristics

Crew: 2
Length: 32 ft 8 in (9.96 m)

XV-4B 32.66 ft (10 m)

Wingspan: 25 ft 8 in (7.82 m)

XV-4B 25.66 ft (8 m)

Height: 11 ft 9 in (3.58 m)

XV-4B 12.25 ft (4 m)

Wing area: 104.00 sq ft (9.662 m²)
Empty weight: 4,995 lb (2,266 kg)

XV-4B 7,463 ft (2,275 m)

Gross weight: 7,200 lb (3,266 kg)

XV-4B 12,580 ft (3,834 m)

Powerplant: 2 × Pratt & Whitney JT12A-3LH turbojet, 3,300 lbf (15 kN) thrust each take-off thrust^[3]
Powerplant: 6 × General Electric J85-GE-19 turbojets, 3,015 lbf (13.41 kN) thrust each XV-4B only, 4 for lift,2 for horizontal flight

Performance

Maximum speed: 518 mph; 450 kn (833 km/h) at 10,000 ft (3,048 m)

XV-4B 463 mph (745 km/h)

Cruising speed: 390 mph; 339 kn (628 km/h)
Range: 600 mi; 521 nmi (965 km) normal
VTO range: 600 mi (966 km)
Rate of climb: 12,000 ft/min (61 m/s)
Wing loading: 69.2 lb/sq ft (338 kg/m²)
Thrust/weight: 1.176 lb/lbst (0.0115 kg/kN)

XV-4B 1.43 lb/lb (0.014 kg/kN)

Notes

1 2 "Hummingbird A Promising Augmented-Jet VTOL Aircraft" Flight International, 3 April 1962
↑ Francillon, Rene J. (1988). Lockheed Aircraft since 1913 (Reprint ed.). London: Putnam & Company Ltd. pp. 432–434. ISBN 0-87021-897-2.
↑ "The Engines of Pratt & Whitney:A Technical History" Jack Connors,published by AIAA, ISBN 978-1-60086-711-8, p.287

References

X-Planes and Prototypes by Jim Winchester

External links

Wikimedia Commons has media related to Lockheed XV-4 Hummingbird.

VSTOL.org Wheel

Lockheed and Lockheed Martin aircraft

Airliners and civil transports	Vega Model 8 Sirius Altair Model 9 Orion Model 10 Electra Model 12 Electra Junior Model 14 Super Electra Model 18 Lodestar Constellation L-049 L-649 L-749 L-1049 Super Constellation L-1249 Super Constellation L-1649 Starliner Saturn L-188 Electra L-402 JetStar L-100 Hercules L-1011 TriStar

Military transports	C-69 Constellation C-121 Constellation C-130 Hercules C-130J Super Hercules HC-130 KC-130 LC-130 MC-130 C-141 Starlifter C-5 Galaxy R6V Constitution Tristar (RAF)

Attack and bombers	YP-24 Hudson XB-30 Ventura AC-130 A-4AR Fightinghawk F-117 Nighthawk Have Blue FB-22

Drones/UAVs	AQM-60 Kingfisher D-21 Desert Hawk Desert Hawk III MQM-105 Aquila Polecat RQ-3 Darkstar RQ-170 Sentinel DC-130

EW and reconnaissance	YO-3 EC-121 Warning Star EC-130 EC-130H Compass Call WC-130 EP-3 U-2 TR-X A-12 SR-71 Blackbird

Fighters	XFM-2 YP-24 P-38 Lightning XP-49 XP-58 Chain Lightning P-80 Shooting Star XF-90 F-94 Starfire F-104 Starfighter variants YF-12 F-16 Fighting Falcon F-22 Raptor YF-22 F-35 Lightning II

Helicopters	CL-475 XH-51 AH-56 Cheyenne VH-71 Kestrel

Maritime patrol	P-2 Neptune P-3 Orion P-7 S-3 Viking CP-140 Aurora

Trainers	T-33 T2V SeaStar

Experimental	L-133 NF-104A Senior Peg Senior Prom XC-35 XF-104 XV-4 Hummingbird X-7 X-17 X-26B Frigate CL-1200 Lancer X-33 X-35 X-44 X-55 X-56 XFV

Other	Air Express Big Dipper Model 44 Excalibur Explorer Little Dipper

United States Army VTOL aircraft designations (1956–62)

VZ-1 VZ-2 VZ-3 VZ-4 VZ-5 VZ-6 VZ-7 VZ-8 VZ-9 VZ-10 VZ-11 VZ-12

United States tri-service STOL and VTOL aircraft designations post-1962

OV-1 CV-2 XV-3 XV-4 XV-5 V-6 CV-7 XV-8 AV-8A/B XV-9 OV-10 XV-11 OV-12 XFV-12 V-13¹ V-14¹ XV-15 AV-16 V-17¹ UV-18 V-17¹ UV-20 V-21¹ V-22 UV-23

¹ Not assigned

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