Bell H-13 Sioux

The H-13 Sioux was a two-bladed, single engine, light helicopter built by Bell Helicopter. Westland Aircraft manufactured the Sioux under license for the British military as the Sioux AH.1 and HT.2.

Development

In 1947, the United States Army Air Forces (later the United States Air Force) ordered the improved Bell Model 47A. Most were designated YR-13 and three winterized versions were designated YR-13A. The United States Army first ordered Bell 47s in 1948 under the designation H-13. These would later receive the name Sioux.^[2]

Initially, the United States Navy procured several Bell 47s, designated HTL-1, between 1947 and 1958. The United States Coast Guard evaluated this model, and procured two HTL-1s for multi-mission support in the New York Harbor. The most common U.S. Navy version of the 47 was designated the HTL-4, and dispenses with the fabric covering on the tail boom. The U.S. Coast Guard procured three HTL-5s in 1952 (similar to the HTL-4 but powered by a Franklin O-335-5 engine) and used these until 1960.^[3] The Coast Guard procured two of Bell's Model 47G and designated them HUL-1G in 1959.^[3]

The H-13 was used as observation helicopter early in the Vietnam War, before being replaced by the OH-6 Cayuse.

The Bell 47 was ordered by the British Army as the Sioux to meet specification H.240, with licensed production by Westland Helicopters. In order to comply with the terms of its licence agreement with Sikorsky Aircraft, which prevented it building a U.S. competitors aircraft, Westland licenced the Model 47 from Agusta, who had purchased a license from Bell.^[4] the first contract was for 200 helicopters. The first 50 helicopters of the contract were built by Agusta at Gallerate in Italy followed by 150 built by Westland at Yeovil. The first Westland Sioux made its maiden flight on 9 March 1965.^[5]

Design

The Sioux is a three-seat observation and basic training helicopter. In 1953 the Bell 47G design was introduced. It can be recognized by the full bubble canopy, exposed welded-tube tail boom, saddle fuel tanks and skid landing gear.

The H-13 and its military variants were often equipped with medical evacuation panniers, one to each skid, with an acrylic glass shield to protect the patient from wind.

A single 260 hp Lycoming VO-435 piston engine was fitted to the 47G variant. Fuel was fed from two high-mounted external tanks. A single two-bladed rotor with short inertial stabilising minor blades was used on the Sioux.^[5]

Variants

Military

YR-13/HTL-1^{[note 1][6]}

28 Bell 47A helicopters procured by the United States Army Air Forces for evaluation. The YR-13 was powered by a 175 hp (130 kW) Franklin O-335-1 piston engine. 10 of the aircraft were evaluated by the U.S. Navy as trainers.

YR-13A

3 YR-13 aircraft winterized for cold-weather testing in Alaska. Redesignated YH-13A in 1948.^[7]

HTL-2

US Navy equivalent of the commercial Model 47D. 12 built.

HTL-3

US Navy equivalent of the commercial Model 47E, powered by a 200 hp (149 kW ) Franklin 6V4-200-C32 engine. Nine built.

H-13B

65 aircraft ordered in 1948 by the U.S. Army.^[7] All Army versions were later named Sioux.

YH-13C

One H-13B used as engineering testbed. Fitted with skid undercarriage and open, uncovered tailboom.^[7]

H-13C

16 H-13B aircraft converted to carry external stretchers in 1952, with skid landing gear and open tail boom of YH-13C.^[7]

H-13D

Army two-seat version based on commercial model 47D-1, with skid landing gear, stretcher carriers, and Franklin O-335-5 engine. 87 built.^[7]

OH-13E

H-13D configuration with three-seat aircraft with dual controls. 490 built.^[7]

XH-13F/Bell 201 

Modified Bell 47G powered by a Continental XT51-T-3 (Turbomeca Artouste) turboshaft.^[7] The first Bell helicopter powered by a turbine engine.

OH-13G

Three-seater based on commercial model 47-G. Introduced a small elevator on the tailboom. 265 delivered to US Army.^[8]

OH-13H/UH-13H

Based on 47G-2. Equipped with a 250 hp (186 kW) Lycoming VO-435 engine. At least 453 acquired by US Army.^[8] UH-13Hs were used by the U.S. Air Force.

UH-13J

Two Bell 47J-1 Rangers acquired by the U.S. Air Force for VIP transport of the U.S. President. Originally designated as H-13J.

OH-13K

Two converted H-13Hs with a larger diameter rotor and a 225 hp (168 kW) Franklin 6VS-335 engine for test evaluation.

TH-13L

Originally designated as the Navy HTL-4.

HTL-5

Utilized a Lycoming O-335-5 engine.

TH-13M

Incorporated a small movable elevator. Originally designated as the Navy HTL-6.

HH-13Q

Originally the HUL-1G, it was used by the U.S. Coast Guard for search and rescue.

UH-13R

Powered by an Allison YT63-A-3 turbposhaft engine. Original US Navy designation HUL-1M.

OH-13S

Three-seat observation helicopter based on 47G-3B to replace the OH-13H. 265 received by US Army.^[8]

TH-13T

Two-seat instrument trainer for the U.S. Army based on the 47G-3B-1, powered by 270 hp (201 kW) Lycoming TVO-435-D1B. 411 purchased.^[8]

Sioux AH.1

General purpose helicopter for the British Army, 50 built by Agusta (Agusta-Bell 47G-3B1) and 250 built by Westland (Westland-Augusta-Bell 47G-3B1).^[9]

Sioux HT.2

Training helicopter for the Royal Air Force, 15 built by Westland.

Operators

 Argentina

• Argentine Navy - Argentine Naval Aviation
• Argentine Naval Prefecture

 Australia

65 Bell 47 Sioux helicopters were in service with both the Australian Army and RAAF from 1960 to 1977.

• Australian Army - Australian Army Aviation
  • No. 16 Army Light Aircraft Squadron
  • No. 183 Squadron
  • No. 162 Flight
  • No. 171 Flight
  • No. 182 Flight
• Royal Australian Air Force
  • No. 16 Air Observation Post Flight RAAF

 Austria

• Austrian Air Force

 Brazil

• Brazilian Air Force

 Canada

• Royal Canadian Navy

 Chile

 Republic of China

 Colombia

 Cuba

 Denmark

• Royal Danish Air Force
  • (722nd squadron) in cooperation with Geus

 Dominican Republic

 Ecuador

 France

 Gabon

 Germany

• German Army
• Luftwaffe

 Greece

 Guatemala

 Iceland

• Icelandic Coast Guard

 Indonesia

 India

 Israel

• Israeli Air Force

 Italy

 Jamaica

• Jamaica Defence Force

 Japan

• Japan Ground Self Defence Force
• Japan Maritime Self Defence Force

 South Korea

 Libya

 Madagascar

 Malaysia

 Malta

 Mexico

 New Zealand

• Royal New Zealand Air Force
  • No. 3 Squadron RNZAF

 Pakistan

• Pakistan Air Force

 Paraguay

 Peru

• Peruvian Air Force
• Peruvian Naval Aviation
• Peruvian Army Aviation

 Philippines

• Philippine Air Force

 Senegal

 South Vietnam

• Vietnam Air Force

 South Yemen

 Spain

 Sri Lanka

 Sweden

 Thailand

 Turkey

 United Kingdom

• British Army Army Air Corps^{[5] [10]}
• Royal Air Force
  • Central Flying School
• Royal Marines
  • 3 Commando Brigade

 United States

• United States Army
• United States Air Force
• United States Navy
• United States Marine Corps
• United States Coast Guard

 Uruguay

 Venezuela

 Yugoslavia

 Zaire

 Zambia

Survivors

• The Pueblo Weisbrod Aircraft Museum, Pueblo, Colorado has a restored H-13G with a "M*A*S*H" look.
• The National Museum of Naval Aviation at NAS Pensacola has a HTL-4 on display, hanging from the ceiling.
• The Museum of Modern Art (MoMA) in New York City has a Bell 47D1 on permanent display.
• Castle Air Museum in Atwater, CA has a Bell H-13 with the M*A*S*H paint scheme in their "Hidden aircraft collection".
• Adventure Aviation in Tauranga, New Zealand uses a Bell 47G in a "M*A*S*H" paint scheme for tourist scenic flights.^[11]
• Bell 47G-2 AS7201 of the Armed Forces of Malta was formally retired on May 30, 2008 and donated to the Malta Aviation Museum at Ta'Qali.
• The United States Army Medical Museum located on base at Fort Sam Houston, in San Antonio Texas, has a Bell 47 on display with other helicopters.
• Wings of Freedom Aviation Museum located in Horsham, PA has an H-13 on display.
• H-13 on display at the War Memorial of Korea, Seoul, Republic of Korea
• The American Helicopter Museum & Education Center in West Chester, Pennsylvania has a restored Bell 47D1 converted to an H-13 and painted in "M*A*S*H" configuration. ^[12]
• The Royal Thai Air Force Museum, Bangkok, Thailand has an OH-13H on display^[13]

Specifications (Sioux AH.1)

Data from Newark Air Museum,^[14] Britains Small Wars.^[15]

General characteristics

• Crew: 1
• Capacity: 3
• Length: 31.6 ft 0 in (9.63 m)
• Main rotor diameter: 2× 37 ft 0 in (11.30 m)
• Height: 9.7 ft 0 in (2.95 m)
• Gross weight: 2952 lb (1339 kg)
• Powerplant: 1 × Lycoming TVO-435-A1A, 260 hp (194 kW)

Performance

• Maximum speed: 105 mph (169 km/h)
• Cruise speed: 84 mph (135 km/h)
• Range: 273 miles (439 km)
• Service ceiling: 16100 ft (4907 m)

Armament

• The OH-1 was capable of carrying twin M37C.30 caliber machine guns, or twin M60 machine guns.^[16] They rarely did so however, because according to a Military Channel documentary on the AH-1 attack helicopter ("World's Deadliest Aircraft" series), the guns' recoil was too great a strain on the engines.

Popular culture

The Bell 47 appeared, and played key roles, in film and television productions. It has been associated with both the M*A*S*H film, and the M*A*S*H television series, and the Whirlybirds TV series (1957–1959).^[17]

See also

Related development

• Bell 47
• H-13J Sioux
• Bell 207 Sioux Scout
• XH-13F
• Kawasaki KH-4
• Agusta A.115
• Meridionali/Agusta EMA 124
• Carson Super C-4
• Continental Copters El Tomcat
  

Aircraft of comparable role, configuration and era

• OH-23 Raven
• TH-55 Osage
• Schweizer 300
  

Notes

References

Footnotes

Bibliography

External links

• Bell 47.net
• Bell 47 Enthusiast site
• Model 47G specs from The International Directory of Civil Aircraft by Gerard Frawley