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Bell H-13 Sioux

United States (1947)
Picture of Bell H-13 Sioux Light Utility / Observation Helicopter
Picture of Bell H-13 Sioux Light Utility / Observation Helicopter Picture of Bell H-13 Sioux Light Utility / Observation Helicopter
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The Bell H-13 Sioux became the militarized evolution of the famous Bell Model 47 line.

Detailing the development and operational history of the Bell H-13 Sioux Light Utility / Observation Helicopter.  Entry last updated on 6/7/2018. Authored by Staff Writer. Content ©

The "helicopter" saw development during World War 2 (1939-1945) and some were in fact used by the Germans in the latter phases of the conflict. For the United States, Bell Helicopters had adopted the designs of Arthur M. young which gave rise to the Model 30 prototype. This prototype then became the basis for the famous Model 47 of which 5,600 were produced from 1946 to 1974 and utilized by a plethora of global operators in both civilian and military guises. The United States Army adopted the Model 47 under the designation of H-13 "Sioux" and this little helicopter served extensively through the Korean War (1950-1953) while seeing some used in the early phases of the Vietnam War (1950-1975) as well. Approximately 2,400 examples of this form were built and stocked the inventories of many global militaries. First flight of the prototype was recorded on December 8th, 1945. The platform served the US Army, Air Force and Navy during its long tenure while UK-based Westland produced the type under license as the Sioux AH.1/HT.2.

The H-13 marked the first large-scale procurement of a helicopter into the US military inventory and became the first helicopter type aircraft to arrive in the Korean Theater of War. It also marked the first US Army helicopter to carry an American Indian tribal name ("Sioux"), still a practice today as proven by the Boeing AH-64 "Apache" and Bell OH-58 "Kiowa".

At its core, the foundation of the Model 47 was clearly apparent in the H-13. The design would eventually evolve into the "classic" Model 47 "look" complete with bubble canopy, skeletal tail unit and skid undercarriage. Their utilitarian appearance granted them utilitarian-minded roles in military service - from light scout to MEDEVAC among many others. There was seating for two to three persons in standard forms while power was served through a Franklin or Lycoming engine. In either guise, the powerplant of the H-13 was used to drive a two-blade main rotor and a two-blade tail rotor, the latter as an anti-torque feature to counter the pull presented by the main rotor blades.

The initial militarized Model 47 fell to the US Air Force as the YR-13 (Model 47A) in 1947 - 28 airframes following - and these were powered by a Franklin O-335-1 piston engine of 175 horsepower. YR-13A models were "winterized" for Arctic use in Alaskan airspace and saw three examples produced. In 1948, the US Army followed suit and ordered the line as the H-13. US Navy models were designated HTL-1 with the HTL-2 being based on the civilian Model 47D and twelve examples were produced. HTL-3 was based on the Model 47E and outfitted with the Franklin 6V4-200-C32 engine of 200 horsepower. Nine examples were produced. HTL-4 became the definitive mark of the US Navy line and was redesignated as TH-13L. HTL-5 was outfitted with the Lycoming O-33505 engine. TH-13M was the HTL-6 redesignated and featuring an added elevator.

H-13B served the US Army from 1948 onwards and numbered 65 examples in production. YH-13C was reserved as an active testbed and begat the H-13C production mark of which sixteen emerged as conversions from the H-13B line. The H-13D was a basic two-seat observation model based on the Model 47D-1 and powered by a Franklin O-335-5 series engine. 87 were produced in all. The OH-13E was an H-13D with seating for three and dual-controls for both pilot positions - 490 were produced. XH-13F was the Model 47G airframe modified to take on the Continental XT51-T3 turbine engine. The OH-13G was a three-seat form of the Model 47G and 265 were accepted by the US Army. The OH-13H was the Model 47G-2 powered by a Lycoming VO-435 engine of 250 horsepower. US Army usage numbered 450 examples while the USAF took stock of some as the UH-13H. The UH-13J (H-13J) were a pair of revised Model 47J-1s for USAF VIP service. The OH-13K were a pair of modified H-13H models with a Franklin 6VS-335 engine of 225 horsepower to serve as testbeds. OH-13S was adopted by the US Army across 265 examples and were Model 47G-3Bs with seating for three. The TH-13T was a trainer variant based on the Model 47G-3B-1 and outfitted with the Lycoming TVO-435-D1B engine of 270 horsepower. At least 411 were taken on by the US Army.

Sioux AH.1 models were a British Army mark - the Model 47G-3B1 produced in 250 examples by Westland. The Sioux HT.2 was its trainer derivative and served the Royal Air Force through 15 examples manufactured by Westland. Italian-based Agusta produced the AH.1 as well and this numbered 50 examples.

Picture of the Bell H-13 Sioux Light Utility / Observation Helicopter
Picture of the Bell H-13 Sioux Light Utility / Observation Helicopter

Operators beyond the United States, United Kingdom and Italy proved plentiful and included Argentina, Australia, Brazil, Canada, France, Germany, Greece, Indonesia, India, Japan, Malaysia, Mexico, New Zealand, the Philippines, Spain, Thailand, Turkey and Venezuela among others (see variants section for full listing).

During the Korean War, the H-13 was utilized in various battlefield roles. Its size made them air-transportable in the hold of a Fairchild C-119 "Flying Boxcar" lifter. Some 56 H-13s were available at the beginning of the war in 1950, this stock made up primarily of YH-13A and H-13B models. The initial group to arrive in Korea was the 2nd Helicopter Detachment during November of 1950.

While the aircraft is primarily remembered for its MEDEVAC service through M.A.S.H. ("Mobile Army Surgical Hospital"), the type proved equally valuable in reconnaissance, wire-laying, mission liaison, general service and pilot training roles. Controls were relatively simple and the instrument panel compact while the transparent canopy offered excellent vision out of the cockpit for both crew. As a trainer, it was the stepping stone for pilots entering the H-19 "Chickasaw" piloting program. It also served as a training platform for Transportation Corps prior to their arrival in Korea and for Apollo astronauts to experience auto-rotation sink rates.

Of course the moving of wounded played a crucial role to Army/Air Force operations across the Peninsula where an H-13 could carry a pair of medical litters over the unforgiving Korean terrain to provide faster assistance to the wounded - speedier than any all-terrain vehicle could over miles of uneven, rocky land. Over time, modifications were added to patient areas such as heat and protection from the elements to provide some comfort thousands of feet in the air. Blood replacement could even be handled by way of a plasma bottle holder fitted to the inside of the crew cabin. H-13s provided such a valuable service in the war that they were dubbed "Angles of Mercy". Indeed, a single H-13 pilot was credited with moving some 922 personnel through 545 sorties in a term lasting 14 months.

In 1952, the H-13 took part in a pair of large-scale resupply operations. The first one lasted seven days and involved just a single H-13 hauling some 20,000lbs to awaiting combat engineers atop a mountain. In the second, lengthier, 10-day operation, several H-13s hauled 17,000lbs of goods and reinforcements to allied infantry elements 800 yards behind enemy lines, also atop a mountain.

While typically unarmed, some Army H-13S models were outfitted with skid-mounted air-to-surface rockets and could additionally mount a pair of 0.30 caliber machine guns. Anti-tank missiles were photographed on at least one H-13, the missiles held outboard along wide spanning structural appendages. H-13 operations could also benefit from accompanying Bell UH-1 "gunships" better armed to provide covering fire and support in enemy-controlled areas.

The H-13 persevered into the Cold War years and saw extended service in the Vietnam War. At the start of the conflict, there were 861 H-13s in service. December of 1961 saw the arrival of the 8th and 57th Transportation Companies at Saigon and these were made up of OH-13E and CH-21 models. Operations continued into 1962 primarily in an observation role. H-13s were eventually superseded in the US Army inventory by the more modern Bell OH-58 "Kiowa" series of 1969.

While no longer in widespread use, some H-13 and related models still serve in an active role with militaries and civilian parties of the world.

General Assessment (BETA)
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Rating: 52 (of 100)
The rating is an internal assessment derived from forty factors pertaining to this entry.
Relative Maximum Speed Rating
Hi: 120mph
Lo: 60mph
    This entry's maximum listed speed (106mph).

    Graph average of 90 miles-per-hour.
City-to-City Ranges
Graph showcases the Bell Sioux AH.1's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
Pie graph section
Pie graph section
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Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.

Altitude Visualization
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National Flag Graphic
Origin: United States
Year: 1947
Type: Light Utility / Observation Helicopter
Manufacturer(s): Bell Helicopters - USA
Production: 2,400
Status: Retired, Out-of-Service
Global Operators:
Argentina; Australia; Austria; Brazil; Canada; Chile; Colombia; Cuba; Ecuador; France; Germany; Greece; Iceland; Indonesia; India; Italy; Jamaica; Japan; Malaysia; Malta; Mexico; New Zealand; Norway; Paraguay; Peru; Philippines; Senegal; South Yemen; Spain; Thailand; Turkey; United Kingdom; United States; Uruguay; Venezuela
Historical Commitments / Honors:

Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.
Measurements and Weights icon
Structural - Crew, Dimensions, and Weights:
Unless otherwise noted the presented statistics below pertain to the Bell Sioux AH.1 model. Common measurements, and their respective conversions, are shown when possible.




31.59 ft

9.63 m


37.07 ft

11.3 m


9.68 ft

2.95 m


3,086 lb

1,400 kg

Engine icon
Installed Power - Standard Day Performance:
1 x Lycoming TVO-435-A1A engine developing 260 horsepower while driving two-bladed main rotor and two-bladed tail rotor.


106 mph

170 kph

92 kts


273 mi

440 km

Nautical Miles
238 nm


16,076 ft

4,900 m

3.04 mi

Supported Weapon Systems:

Graphical image of an aircraft medium machine gun
Graphical image of an aircraft anti-tank guided missile
Graphical image of aircraft aerial rockets
Armament - Hardpoints (2):

Typically none though some wartime variants were fielded with 2 x 0.30 caliber medium machine guns, aerial rockets, or 2 x Air-to-surface anti-tank missiles on outboard skid mountings.
Variants: Series Model Variants
• H-13 - Base series designation
• YR-13 - USAF/Army mark
• HTL-1 - US Navy mark
• YR-13A - Winterized YR-13 models; 3 examples
• H-13B - US Army model; 65 examples
• YH-13C - H-13B aircraft serving as testbed; single example.
• H-13C - H-13B modified with skeletal empennage and skid undercarriage; 16 examples.
• H-13D - US Army Model 47D-1; two-seat variant with Franklin O-335-5 engine; 87 examples.
• OH-13E - H-13D with dual-controls and seating for three; 490 examples.
• XH-13F - Model 47G with Continental XT51-T-3 turbine engine.
• OH-13G - Model 57G with seating for three; elevator on tailboom; 265 examples.
• OH-13H - Model 47G-2 with Lycoming VO-435 engine of 250 horsepower; 453 examples.
• UH-13H - USAF designation of OH-13H
• UH-13J - Model 47J-1 Rangers for USAF VIp use; two examples.
• OH-13K - H-13H models with larger-diameter main rotor blades; powered by Franklin 6VS-335 engine.
• HH-13Q - US Coast Guard SAR model; originally as the HUL-1G.
• HUL-1G - US Coast Guard model designation of HH-13Q.
• UH-13R - Powered by Allison YT63-A-3 turboshaft engine; redesignated from HUL-1M.
• HUL-1M - Original US Navy designation for UH-13R
• OH-13S - Model 47G-3B three-seat scout; 265 examples.
• TH-13T - Trainer version based on Model 47G-3B-1; fitted with Lycoming TVO-435-D1B engine; 411 examples.
• HTL-2 - US Navy Model 47D; 12 examples
• HTL-3 - US Navy Model 47E; fitting Franklin 6V4-200-C32 engine of 200 horsepower; nine examples.
• HTL-4 - Redesignated to TH-13L
• HTL-5 - Fittng Lycoming O-335-5 engine
• HTL-6 - Added elevator; redesignated to TH-13M
• TH-13L - Redesignated HTL-4 model
• TH-13M - Redesignated HTL-6 model
• Sioux AH.1 - British/Italian Army models based on Model 47G-3B1; 250 produced by Westland and 50 by Agusta.
• Sioux HT.2 - Trainer variant for RAF; 15 examples produced under Westland Aircraft.