Back Bell Model 47 "Sioux"

Bell 47

The Bell Model 47 was ordered for the US Army and Navy towards the end of World War II and first flew in 1945. The pre-production model had a 178hp Franklin engine and a car-type body. Only ten were built, but some were airborne as early as 1943. However, the Model 47 has the distinction of being the first helicopter to receive a CAA (Civil Aviation Administration) approval certificate, which was granted on March 8, 1946. The A and B models used the enclosed body. The 47B-3, a utility and agricultural model, had an open sports-car style body and it was from this design that the now familiar goldfish bowl moulded canopy was derived. The FAA (Federal Aviation Administration) certified the 47D with its new canopy in February 1948. A year later Bell produced the 47D-1 with an openwork tail boom.

The three-seat configuration, later combined with a 200hp Franklin engine, produced the 47G which was granted an FAA certificate in 1953. This became one of the most successful versions remaining in production in improved forms into the 1970s. It was adopted by a wide range of civil and government operators for survey work, traffic control, coastguard work, crop-spraying (using the AgMaster chemical application system) and as an executive transport.

Not content with this success Bell have developed further models and in 1955 they installed a new powerplant. The 200hp Lycoming VO-435 allowed the helicopter to operate at greater weights but without a fall-off in performance.

In 1952 Agusta SpA of Italy was granted a licence to build the Bell 47 and produced its first 47G in 1954. Since then Agusta has built over 1000 G and J marks. Kawasaki in Japan received a licence a year later and like Agusta developed its own versions of the Bell originals.

The Bell 47H with a fully enclosed car-type cabin and 200hp engine was not a commercial success, but in the early 1960s the J series sold well. Seating four in an enclosed cabin, it was powered by a 220hp Lycoming VO-435 engine. With power controls and metal rotor blades in the Model 47J-2 in 1960 it became popular as an executive transport. Agusta produced a three-seat version as the EMA 124 and though Bell have stopped production the G and J series are still being built in Italy and Japan.

Bill Gunston "The Illustrated Encyclopedia of Commercial Aircraft", 1980

On 8 December 1945, Bell flew the prototype of a classic helicopter design, the Bell Model 47. On 8 March 1946 this was awarded the first Approved Type Certificate issued for a civil helicopter anywhere in the world. The type remained in continuous production by Bell into 1973, and was also built under licence by Agusta in Italy from 1954 to 1976. The Model 47 has been used on a large scale by armed forces all over the world, its simplicity and low cost more than outweighing its limited capabilities.

In 1947 the USAF (then USAAF) procured 28 of the improved Model 47A, powered by 117kW Franklin O-335-1 piston engines, for service evaluation: 15 were designated YR-13, three YR-13As were winterised for cold-weather trials in Alaska, and the balance of 10 went to the US Navy for evaluation as HTL-1 trainers. Little time was lost by either service in deciding that the Model 47 was an excellent machine, and the orders began to flow in.

The US Army's first order was issued in 1948, 65 being accepted under the designation H-13B; all US Army versions were later named Sioux. Fifteen of these were converted in 1952 to carry external stretchers, with the designation H-13C. Two-seat H-13Ds with skid landing gear, stretcher carriers, and Franklin O-335-5 engines followed, and generally similar three-seat dual control H-13Es. The H-13G differed by introducing a small elevator, and the H-13H introduced the 186kW Lycoming VO-435 engine. Some of the H-13Hs were used also by the USAF, as were two H-13Js with 179kW Lycoming VO-435s acquired for the use of the US President. Two H-13Hs converted for trial purposes, with an increased-diameter rotor and 168kW Franklin 6VS-335 engine, were designated H-13K. In 1962 US Army H-13E, -G, -H and -K aircraft were redesignated with the prefix letter O, for observation. US Air Force H-13Hs and H-13Js were given the U prefix as utility helicopters. Later acquisitions were the three-seat OH-13S to supersede the OH-13H, and the TH-13T two-seat instrument trainer.

US Navy procurement began with 12 HTL-2s and nine HTL-3s, but the first major version was the HTL-4, followed by the HTL-5 with an O-335-5 engine. HTL-6 trainers incorporated the small movable elevator. The HUL-1 was acquired for service on board ice-breaking ships, and the final HTL-7 version for the US Navy was a two-seat dual-control instrument trainer with all-weather instrumentation. In 1962 the HTL-4, HTL-6, HTL-7 and HUL-1 were redesignated respectively TH-13L, TH-13M, TH-13N and UH-13P

The Model 47 has been built under licence by Agusta in Italy, Kawasaki in Japan, and Westland in the UK (the 47G-2 for the British Army, with the name Sioux), and in various roles Model 47s have served with more, than 30 armed services.

Experimental versions have been numerous. Perhaps the two most important were the Bell Model 201 (service designation XH-13F) and the Bell Model 207 Sioux Scout. The Model 201 was powered by a Continental XT51-T-3 (licence-built Turbomeca Artouste) turboshaft. The Model 207 was the first true armed helicopter: powered by the 194kW turbocharged Avco Lycoming TVO-435-A1A piston engine, the Sioux Scout featured a revised cabin seating two in tandem, small stub wings containing additional fuel and helping to offload the main rotor in forward flight, and a remotely controlled chin barbette, containing two 7.62mm M60 machine-guns, and movable 200° in azimuth, with elevation from -45° to +15°.

In parallel with production of military aircraft, by both Bell and its licencees, there were civil versions for a wide variety of purposes. These have included the Model 47B (equivalent to the military YR-13/HTL-1), and the agricultural/utility Model 47B-3 with open crew positions. The following Model 47D was the first to appear with a moulded 'goldfish bowl' canopy, and the Model 47D-1 of 1949 introduced an openwork tailboom as on the H-13C.

A first important change came with introduction of the Model 47G, which combined the three-seat capacity of the Model 47D-1 with a 149kW Franklin engine. Substitution of the similarly powered Avco Lycoming VO-435 resulted in the Model 47G-2 (H-13H). A 179kW VO-435 engine brought the changed designation Model 47G-2A, followed in 1963 by the wider cabin Model 47G-2A-1 with improved rotor blades and increased fuel capacity. Other engine installations included a 168kW supercharged Franklin 6VS-335-A (Model 47G-3); 209kW turbocharged Avco Lycoming TVO-435 (47G-3B); and normally aspirated Avco Lycoming VO-540 and VO-435 engines in the three-seat utility Model 47G-4 and Model 47G-5 re spectively. A two-seat agricultural version of the latter was known as the Ag-5, and a civil version of the USAF's H-13J VIP transport was marketed as the VO-435 engines in the three-seat utility Model 47G-4 and Model 47G-5 respectively. A two-seat agricultural version of the latter was known as the Ag-5, and a civil version of the USAF's H-13J VIP transport was marketed as the Model 47J Ranger. Bell's production of Model 47s eventually came to an end in late 1973, versions of the Model 47G-5 being the last to be built.

Agusta in Italy, and Kawasaki in Japan, both produced helicopters comparable to some of Bell's civil Model 47s, and added variants of their own. In addition there have been specialised conversions by at least two American companies, including a high-performance Carson Super C-4, and a number of El Tomcat agricultural aircraft developed by Continental Copters Inc. Turboshaft conversions of several models have been produced by Soloy in the USA.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

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Developed version of Model 30 (third prototype configuration) with two side-by-side seats, open cockpit (but later removable transparent bubble), four-leg wheel u/c, open frame rear fuselage with tail skid (later tubular tail rotor protector), ventral fin and one 175hp Franklin engine driving two-blade wooden main rotor. Prot. NC41962/NC1H FF 8 Dec. 1945.

47A / YR-13 / YH-13 / HTL-1

USAF version of Model 47 as YR-13 with enclosed rear fuselage and tail boom, powered by one 175hp Franklin O-35-1 engine. 28 built.

47A / YH-13A


Three YH-13 modified for cold weather operations.


Two-seat commercial Model 47 with enclosed tailboom, fully enclosed fuselage with stepped windshield, under-nose transparencies and two car-type doors, four-leg u/c. Powered by one 178hp Franklin 6V4-178-B3 piston engine. 992kg TOGW. Prot NX41967.


Model 47 for crop dusting with modified open cockpit, engine compartment fairing, and externally mounted dusting hoppers. One 178hp Franklin 6V4-178-B32 piston engine.


Model 47B-3 with improved plexiglass canopy, new wheel installation with brakes, 24 volt electrical system, modified fuel system, optional float u/c (47D-S) and 178hp Franklin 6V4-178-B32 engine.

47D / H-13B Sioux / HTL-2

Military model similar to civil 47D with 200hp Franklin O-335-3 and four-leg u/c, bubble canopy with removable top, covered rear fuselage and dual controls. 61 built.

47D / H-13C Sioux


H-13B with uncovered rear fuselage and skid u/c with external medevac litter fittings. 16 built.

47D / H-13D Sioux


H-13C with single pilot controls and 200hp Franklin O-335-5. 88 built.

47D / H-13E Sioux


H-13D with dual controls, three seats, modified main and tail gearboxes and main transmission. Powered by a Franklin O-335-5B. 49 built.


Three-seat Model 47D with open frame fuselage, new canopy, gravity-feed fuel system, ventral fin, roller-bearing transmission, 29-USG fuel capacity, reduced equipment and increased useful load. 937kg TOGW.

47D-1 / HTL-4

US Navy version of Model 47D-1. Later TH-13L. 46 built.

47D-1 / HTL-5

HTL-4 with 200hp Franklin O-335-5 engine.

47E / HTL-3

Two-seat Model 47D with 200hp Franklin 6V4-200-C32 engine, 1060kg TOGW, 33-USG fuel capacity, optional open cockpit.



Three-seat Model 47D with 200hp Franklin 6V4-200-C32AB engine, skid u/c, small tailplane with endplates, relocated battery, revised tail rotor gearbox, synchronised elevator and relocated 43-USG 'saddle' fuel tanks 1060kg TOGW.



Model 47G with 200hp Lycoming VO435-A1A engine, relocated cyclic hydraulic boost controls, bonded metal rotor blades and 1105kg TOGW. Also built by Kawasaki.

47 / H-13G Sioux


Military model similar to 47G-2 with increased fuel and external stretcher fittings. 265 built.

47 / HTL-6


US Navy dual control training version of H-13G. Later TH-13M.

47 / H-13H Sioux


H-13G with 250hp Lycoming VO-435-23 engine, improved skid u/c and all-metal bonded rotor blades. 468 built.



Three-seat Model 47G with 240hp Lycoming VO-435-A1E engine, 1285kg TOGW. Also Kawasaki model.



47G-2A with fuel capacity inc. from 43-USG to 61.6-USG.

47G-3 H-13K Sioux

Civil and military model 47G with 225hp Franklin 6VS-335-A engine, longer rotor blades and 14-inch longer tailboom. 1195kg TOGW.

47G-3B / OH-13S Sioux


Civil and military Model 47G-3 with turbocharged 260hp Lycoming TVO-435-A1A and 1285kg TOGW. 576 built.



Model 47G-3B with 270hp turbocharged Lycoming TVO-435-B1A engine, 8-inch wider 3-seat cabin, 61.6-USG fuel capacity. 1330kg TOGW. Built also by Westland and Agusta.



Model 47G-3B1 with turbocharged 280hp Lycoming TVO-435-G1A. 1330kg TOGW.

47G-3B2 / TH-13T


Two/three seat military instrument trainer with extra IFR equipment. 417 built.



Model 47G-3B2 with TVO-435-F1A engine and 11-inch wider cabin



Model 47G with 260hp Lycoming VO-540-B1 B3 engine, 61.6-USG fuel, hydraulically assisted controls and 1330kg TOGW.



Model 47G-4 with engine uprated to 280hp.


Economy 2-seat version of 47G-4 with 12 volt electrical system. 1285kg TOGW, 28-USG fuel capacity. Can be upgraded to 3-seat configuration with synchronised elevator mod.



3-seat Model 47G-5 with 61.6-USG fuel tanks and 11-inch wider cabin.


Model 47G with fully clad fuselage, wider three-seat deluxe cabin and rear baggage stowage locker, contoured 35-USG fuel tanks, modified skid u/c. 1060kg TOGW.



Four-seat development of Model 47H with single pilot seat and rear 3-place passenger seat. Powered by one 220hp Lycoming VO-435-A1B, 1157kg TOGW and 35-USG fuel capacity.

47J / H-13J


Model 47J for USAF with 240hp Lycoming VO-435-21.

47J / HUL-1

Model 47J for US Navy with 260hp Lycoming VO-435-B1B. Later UH-13P. Also HUL-1G (HH-13Q) for USCG. 25 built.



Model 47J with VO-435A engine.

47J-2 Ranger


Model 47J with 240hp VO-540-B IB engine, metal rotor blades, fixed stabiliser, hydraulic controls, blue tinted bubble and windows, 48-USG fuel capacity and 1285kg TOGW.


Model 47J-2 with 260hp Lycoming VO-540-B 1 B3 engine, collective boost system and 1330kg TOGW. Built by Agusta.



Naval Model 47J-2A with strengthened transmission, improved rotor brake and underslung torpedo. Agusta built.



Model 47J with turbocharged Lycoming TVO-435-B1A engine for high altitude operation and modified servo control system 1330kg TOGW.

47K / HTL-7

US Navy 2-seat trainer based on HUL-1 with modified cockpit and IFR instrumentation. 240hp Lycoming O-435-6 engine. 1157kg TOGW, 35-USG fuel capacity. Later TH-13N. 18 built.

47L / HUL-1M


Experimental Model 47J with 250shp Allison YT-63-A-3 turboshaft and 1285kg TOGW. First a/c Bu. 149838 FF 6 Jan, 1961. Later UH-13R. 2 built.

Kawasaki KH-4


47G-2 "El Tomcat"

Agricultural conversion by Continental Copters with single seat cockpit and two large external hoppers plus underslung spray bars.

Texas Helicopters M-74 "Wasp"


Conversion by Texas Helicopters

Texas Helicopters M-79T "Hornet"


Conversion by Texas Helicopters

JIM BAGGETT, 23.12.2021reply

Got a lot of time in Panma CZ in H-13. Did many emonstrtions withtwin M<-60s. Grease pencil on the bubble for siting in on targets. Mid 60'e

Ken F, e-mail, 24.07.2020reply

I am looking for information on the Bell 47B-3 on your web page. Is it the same one at the Anchorage Alaska International Airport, or if not where is this one now and can I get more info? Is it for sale or going into a museum? I am also looking for blueprints for the same type, model 47B-3. Any help would be appreciated.

Daniel Carlson, e-mail, 23.09.2016reply

Best machine ever made!!!!!! Seeing & hearing one of these in flight sends shivers up & down my spine.

SR71ALPHA, e-mail, 02.08.2010reply

I need the blueprints of this helicopter, if anyone got them.

Jim, e-mail, 23.04.2011reply

My friend Jack flew in a Helicopter in Alaska in 1949. Says blades were laminate with Balsa Wood. Says landing above about seven thousand was called a controlled Crash.

Roger D. Huffaker, e-mail, 02.08.2011reply

After initial helicopter training in the Hiller OH-23D at Fort Wolters - I then checked out in the OH-13E - we fired 30 cal. MGs from them in training at Ft. Sill, OK After graduating from flight training at Wolters - I flew the OH-13H Model in Germany - they were also armed with 30 cal. MGs and served as scout helicopters in an Air Cav Troop.

John varghese, e-mail, 06.06.2013reply

Hai , am John. I want the full detail of mosquito Xe .

John Camp, e-mail, 06.03.2013reply

I seek permission to use the image of the Bell Model 47 "Sioux" at your website as an illustration of late-40s technology in my novel about the Roswell Incident. I expect to self-publish a run of 500 copies and see if the demand exists for more.
Thanks for considering my request,
John C.

kanishka, e-mail, 13.06.2014reply

can any body let me know the availability of moulded canopy for model bell 47 g,,thanks

Reed Carr, e-mail, 21.01.2015reply

Flew the HTL-7 at Ellyson Field in 1957, my first Helo trainer.Loved flying it and always remember the first lift off and hover. I marvelled at the machine. Came back in 1962 to instruct in it. Could really make it perform.

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