Hiller OH-23 Raven

"OH 23" redirects here. OH 23 may also refer to Ohio's 23rd congressional district.

OH-23 Raven

Hiller OH-23
Role	Multipurpose light helicopter
Manufacturer	Hiller Aircraft Corporation
Introduction	1948
Status	Retired
Primary user	United States Army, Colombian Air Force

The Hiller OH-23 Raven was a three-place, light observation helicopter based on the Hiller Model 360. The Model 360 was designated by the company as the UH-12 ("UH" for United Helicopters),^[1] which was first flown in 1948. The OH-23 trainer was jokingly nicknamed the "Hiller Killer" by US Army Aviation student pilots who had to fly it.^[2]

Development

Hiller UH-12A in 1955 when used as a crop spraying demonstrator in England

In 1947, United Helicopters developed the prototype Model 360X helicopter. A year later, on 14 October 1948 the CAA issued a production certificate for the Model 360. United Helicopters began producing the Model 360 as the UH-12. In 1949, the UH-12 became the first helicopter to make a transcontinental flight from California to New York. When Hiller upgraded the engine and the rotor blades, the company designated the new model as the UH-12A. It was the UH-12A that would be adopted by both the French and United States militaries, as well as being used by civil commercial operators in several countries.

Operational history

The H-23 Raven performed as a utility, observation, and MedEvac helicopter during the Korean War. Model numbers ranged A through D, F and G. The H-23A had a sloping front windshield. The H-23B was used as a primary helicopter trainer. Beginning with the UH-23C, all later models featured the "Goldfish bowl" canopy similar to the Bell 47.

The Raven used Hiller's "Rotor-Matic" cyclic control system, with two small servo rotor paddles offset 90 degrees to the main rotor blades. The paddles were attached to the control column, so that movement of the column would cause the pitch of the servo paddles to change, loading the main rotor blade so that the desired cyclic changes to the rotor occurred.^[3] The OH-23 had a top speed of 97 mph (84 knots). The Raven had a two-bladed main rotor, a metal two-bladed tail rotor. Both the OH-23B and the OH-23C were powered by one Franklin O-335-5D engine.

Royal Navy Hiller HTMk1 (HTE-2) of 705 Squadron in 1953

The OH-23D was a purely military version with a 0-435-23C engine and a more reliable transmission. Most OH-23Ds were replaced by the OH-23G, the most common version of the Raven, with a more powerful Lycoming O-540-9A six-cylinder, horizontally opposed, air-cooled 305 hp engine. The OH-23G could seat three. The MEDEVAC version carried two external skid-mounted litters or pods. The Raven saw service as a scout during the early part of the Vietnam War before being replaced by the OH-6A Cayuse in early 1968. A Raven piloted by Hugh Thompson, Jr. played a crucial role in curtailing the My Lai Massacre. The Raven could be armed with twin M37C .30-caliber machine guns on the XM1 armament subsystem or twin M60C 7.62 mm machine guns on the M2 armament subsystem. The XM76 sighting system was used for sighting the guns.

The Royal Navy's No. 705 Training Squadron used Hiller HTE-2s for several years from 1953 and later operated Hiller 12E's for many further years as its basic helicopter trainer based at RNAS Culdrose located in Cornwall, England.

Variants

Early OH-23

Military

YH-23: One Model UH-12A, modified with two-seat cabin and 178 hp Franklin engine for US Army evaluation.^[4]
H-23A: Initial production version with 178 hp (133 kW) Franklin O-335-4 piston engine and two-seat cockpit, 100 built for the US Army^[5] and 5 for evaluation by the US Air Force.^[6]
H-23B: H-23A with skid/wheel undercarriage and 200 hp (149 kW) O-335-6 engine (some later re-engined with a 250 hp VO-435-23B), re-designated OH-23B in 1962, 273 built for the US Army^[5] and 81 for military export.
H-23C: Model UH-12C with three-seat cabin, one-piece canopy and metal rotor blades, 145 built for the US Army. Re-designated OH-23C in 1962.^[5]
H-23D: H-23C with new rotor, transmission and 250 hp (187 kW) Lycoming VO-435-23B engine, 348 built for US Army. Re-designated OH-23D in 1962.^[5]
H-23E: Model UH-12E, not bought
H-23F: Model UH-12E-4, four-seat model with 25-inch cabin extension and a 305 hp VO-540-A1B engine, redesignated OH-23F in 1962, 22 built for US Army.^[5]
H-23G: Three-seat dual control version of H-23F, redesignated OH-23G in 1962, 793 built.^[5]
HTE-1: US Navy version of the Model UH-12A with Franklin O-335 engine, two-seater with dual controls, and wheeled tricycle undercarriage, 17 built.^[7]
HTE-2: US Navy version of H-23B with Franklin O-335-6 engine, 35 built.^[7]^[8]
Hiller HT Mk 1: Royal Navy designation for 20 former US Navy HTE-2s.^[9]
Hiller HT Mk 2: UH-12Es for Royal Navy. 21 supplied.^[9]
CH-112 Nomad: Canadian military designation.

Civilian

UH-12A: Original production model for the US Army, powered by a 178 hp Franklin O-335-4 piston engine. US Army designation H-23A.

Hiller UH-12B

UH-12B: Training version for the US Navy. US Navy designation HTE-1.
UH-12C: Three-seat version, equipped with all-metal rotor blades and one-piece 'goldfish bowl' canopy.

US Army designation H-23C.

UH-12D: Improved version of the H-23C for the US Army. US Army designation H-23D.
UH-12E: Three-seat dual-control version of the H-23D.
UH-12ET: Turbine-powered version of the UH-12E, fitted with an Allison 250 turboshaft engine.
UH-12E3: New three-seat production version.
UH-12E3T: New turbine-powered production version.

Hiller UH-12E4, four seater

UH-12E4: Four-seat civilian version. US Army designation H-23F. VO-540 powered. Conversion kit available for E-12 models.^[10]
UH-12E4T: Four-seat turbine-powered production version.
UH-12L-4: Lengthened version with wider cabin windows.

Operators

Argentina

Canada

Canadian Army^[13]

Chile

Chilean Air Force^[14]

Colombia

Colombian Air Force^[14]

Dominican Republic

Dominican Air Force^[15]

Guatemala

Guatemalan Air Force^[16]

Indonesia

Indonesian Air Force^[16]

Israel

Israeli Air Force OH-23, Jerusalem 1952

Israeli Air Force^[16]

Mexico

Mexican Air Force^[17]

Netherlands

Netherlands Air Force^[18]

Paraguay

Paraguayan Air Force^[19]

Peru

Peruvian Air Force^[20]

South Korea

South Korea Army^[21]^[22]

Thailand

Royal Thai Police^[23]

United Kingdom

United States

Uruguay

Uruguayan Air Force^[27]

Specifications (H-23D)

Data from United States Military Aircraft since 1909^[28]

General characteristics

Crew: 2
Length: 27 ft 9 ¹⁄₂ in (8.47 m)
Rotor diameter: 35 ft 5 in^[29] (10.80 m)
Height: 9 ft 9 ¹⁄₂ in (2.99 m)
Disc area: 985 sq ft (91.5 m²)
Empty weight: 1,816 lb (825 kg)
Max. takeoff weight: 2,700 lb (1,227 kg)
Powerplant: 1 × Lycoming VO-435-23B^[29] 6-cylinder piston engine, 250 hp (187 kW)

Performance

Maximum speed: 95 mph (153 km/h, 83 knots) at sea level
Cruise speed: 82 mph (132 km/h, 71 knots)
Range: 197 mi (317 km, 171 nmi)
Service ceiling: 13,200 ft (4,025 m)
Rate of climb: 1,050 ft/min (5.3 m/s)

Popular culture

A UK registered civil UH-12 was seen attacking James Bond in the 1963 film From Russia with Love. A UH-12E4 (A UK registered civil aircraft with faux U.S. Army markings) was used in the 1964 Bond film Goldfinger. One was also seen in the 1967 Bond film You Only Live Twice.

The 1978 film Attack of the Killer Tomatoes contains footage of a real helicopter crash. A Hiller Aircraft UH-12E, U.S. civil registry N81959, suffered a tail-rotor strike during a scene where the helicopter was supposed to have landed in a tomato patch behind police officers. The aircraft spun out of control, rolled over, and burst into flames. The helicopter pilot escaped without serious injury.^[30]

The type has also been seen in numerous other films.

References

↑ Donald, David. The Complete Encyclopedia of World Aircraft. New York: Barnes & Noble Books, 1998.
↑ Fort Wolters Tour: The Aircraft
↑ Bridgman 1953, pp. 240–241.
↑ Harding 1990, p.141.
1 2 3 4 5 6 Harding 1990, p.142.
↑ Swanborough and Bowers 1963, p.274.
1 2 Swanborough and Bowers 1976, p.440.
↑ "Hiller HTE-2 'Raven'". Aero-web.org. Retrieved 15 November 2009.
1 2 Thetford 1978, p.400.
↑ A.C. Bass (November 1960). "E-4 "Station Wagon"". Flying Magazine.
↑ "World Air Forces 1987 pg. 40". flightglobal.com. Retrieved 23 March 2013.
↑ "Policia de la Provincia de Buenos Aires UH-12E". Retrieved 23 March 2013.
↑ "CH-112 Nomad". canadianwings.com. Retrieved 23 March 2013.
1 2 "World Helicopter Market 1968 pg. 50". bell47.net. Retrieved 2013-03-23.
↑ "World Helicopter Market 1968 pg. 51". flightglobal.com. Retrieved 23 March 2013.
1 2 3 "World Helicopter Market 1968 pg. 52". bell47.net. Retrieved 2013-03-23.
↑ "World Helicopter Market 1968 pg. 53". flightglobal.com. Retrieved 23 March 2013.
↑ "Koninklijke Luchtmacht UH-12E". Retrieved 23 March 2013.
↑ "World Air Forces 1987 pg. 77". flightglobal.com. Retrieved 23 March 2013.
↑ "World Helicopter Market 1968 pg. 54". flightglobal.com. Retrieved 23 March 2013.
↑ "US →South Korea (1966-1967)". armstrade.sipri.org. Retrieved 23 March 2013.
↑ "South Korean Army OH-23". Demand media. Retrieved 23 March 2013.
1 2 "World Helicopter Market 1968 pg. 55". bell47.net. Retrieved 2013-03-23.
↑ "Royal Navy Fleet Air Arm UH-12B HTE-2". Retrieved 23 March 2013.
↑ "World Helicopter Market 1968 pg. 59". flightglobal.com. Retrieved 23 March 2013.
1 2 "The H-23 Raven Helicopter". bell47.net. Retrieved 2013-03-26.
↑ "World Air Forces 1975 pg. 314". flightglobal.com. Retrieved 23 March 2013.
↑ Swanborough and Bowers 1963, p.276.
1 2 Harding 1990, p.143.
↑ "Movie Crash from Attack of the Killer Tomatoes, July 11th, 1978". Retrieved 2010-04-11.

Bridgman, Leonard. Jane's All the World's Aircraft 1953–54. London: Sampson Low, Marston & Co. Ltd, 1953.
Harding, Stephen. U.S. Army Aircraft since 1947. Shrewsbury, UK: Airlife, 1990. ISBN 1-85310-102-8.
Swanborough, F.G. and Bowers, Peter M. United States Military Aircraft since 1909. London: Putnam, 1963.
Swanborough, Gordon and Bowers, Peter M. United States Navy Aircraft since 1911 (second edition). London: Putnam, 1976. ISBN 0-370-10054-9.
Thetford, Owen. British Naval Aircraft since 1912 (fourth edition). London: Putnam, 1978. ISBN 0-370-30021-1.
OH-23 Factsheet

External links

Wikimedia Commons has media related to H-23 Raven.

United Helicopters/Hiller Helicopters/Hiller Aircraft aircraft

Civil helicopters	UH-12 FH-1100

Military helicopters	HTE-1 OH-23 Raven YOH-5 Ten99

Experimental helicopters	YH-32 Hornet YROE X-18 VZ-1 Pawnee

United States helicopter designations, Army/Air Force and Tri-Service systems

Numerical sequence used by USAAC/USAAF/USAF 1941–present; US Army 1948–1956 and 1962–present; US Navy 1962–present

Main sequence
(1941–1962)

Prefix R-, 1941–1948	R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16

Prefix H-, 1948–1962	H-5 H-6 H-9 H-10 H-11 H-12 H-13/J H-15 H-16 H-17 H-18 H-19 H-20 H-21 H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-31 H-32 H-33 H-34 H-35 H-36¹ H-37 H-38¹ H-39 H-40 H-41 H-42 H-43 H-44¹ H-45¹

Main joint sequence
(1962–present)

1962 redesignations	OH-13/UH-13J UH-19 CH-21 OH-23 UH-25 CH-34 CH-37 HH-43

New designations	CH-46/HH-46/UH-46 CH-47 UH-48 XH-49 QH-50 XH-51 HH-52 CH-53/HH-53/MH-53/CH-53E/CH-53K CH-54 TH-55 AH-56 TH-57 OH-58 XH-59 UH-60/SH-60/HH-60/HH-60J YUH-61 XCH-62 YAH-63 AH-64 HH-65 RAH-66 TH-67 MH-68 H-69¹ ARH-70 VH-71 UH-72 H-73 to H-91¹ VH-92

1962 redesignations
reusing old numbers

¹ Not assigned

USN helicopter designations pre-1962

Helicopter, Anti-submarine

Bell	HSL

Sikorsky	HSS-1 HSS-2

Helicopter, Crane

McDonnell	HCH

Helicopter, Observation

Convertawings	HOC

Hiller	HOE

Gyrodyne	HOG

Kaman	HOK

Sikorsky	HOS HO2S HO3S HO4S HO5S

Helicopter, Trainer pre-1948

Sikorsky	HNS

Helicopter, Trainer 1948-1962

Hiller	HTE

Kaman	HTK

Bell	HTL

Helicopter, Transport 1944-1962

Boeing Vertol	HRB

McDonnell	HRH

Piasecki	HRP

Sikorsky	HRS HR2S HR3S

Helicopter, Utility pre-1949

McDonnell	HJD

McDonnell	HJH

Piasecki	HJP

Sikorsky	HJS

Helicopter, Utility 1950-1962

Kaman	HUK HU2K

Bell:	HUL

McCulloch	HUM

Piasecki	HUP

Sikorsky	HUS HU2S

Canadian Forces post-1968 unified aircraft designations

100–119	CF-100 CF-101 102–103 skipped CF-104 CF-105 CC-106 CP-107 CC-108 CC-109 CSR-110 CF-111 CH-112 CH-113 CT-114 CC-115 CF-116 CC-117 CH-118 CO-119 CO-119(2)

120–139	CT-120 CP-121 CP-122 CSR-123/CC-123 CH-124 CH-125 CH-126 CH-127 CT-128 CC-129 CC-130 CX-131 CC-132 CT-133 CT-134 CH-135 CH-136 CC-137 CC-138 CH-139

140–159	CP-140 CC-141 CT-142 CH-143 CC-144/CE-144 CT-145 CH-146 CH-147 CH-148 CH-149 CC-150 151–154 skipped CT-155 CT-156 157–159 skipped CU-160

160–	CU-161 CU-162 CU-163 164–166 skipped CU-167 CU-168 169 skipped CU-170 171–176 skipped CC-177 CH-178 179–187 skipped CF-188

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