Exhibition
Bell 47G2 SIOUX
A classic among helicopters. Produced from 1948 to 1973, more than 6,000 helicopters were built and in use in many countries. The Bell 47 has widely become known by its rescue operations during the Korean War (MASH 4077).
Straightforward, insusceptible rotor construction with stabilizer resulting in safe flight characteristics.
Development Background
On 8 December, 1945, Bell flew the prototype of a classical helicopter construction, the Bell 47 model. On 8 March, 1946, it received the first "Approved Type Certificate" worldwide that had ever been issued to a civil helicopter. This type was produced by Bell until 1973 without any interruption. In addition, it was produced under licence by Agusta in Italy from 1954 to 1976. The Bell 47 was used worldwide by military units; its limited capacity was more than balanced by its simplicity and its low price. In 1947, the USAF (in those days still USAAF) ordered 28 helicopters of the improved Bell 47A model with 157 shp (117 kW) Franklin 0-335-1 piston engines for testing purposes. 15 received the designation YR-13, three machines of the YR-13A type were prepared for tests to be conducted under winter conditions in Alaska, and the remaining ten were transferred to the US Navy for testing, where they were used as HTL-1 trainers. Shortly after, every branch of service came to the conclusion that the Bell 47 was a first-class machine, and orders kept pouring in. The US Army first ordered a series of machines in 1948. 65 were commissioned with the designation H-13B. All US Army version were later renamed to Sioux. In 1952, 15 machines were modified to carry external stretchers. They received the designation H-13C. The H-13D was a double-seated model with a skid landing gear, stretcher support and a Franklin 0-335-5 engine. It was followed by a similar three-seated H-13E with dual control. The H-13G had a small elevator, and for the H-13H the 250 shp (186 kW) Lycoming VO-435 engine was introduced. Some H-13H machines were also being used by the USAF, as well as two H-13J helicopters with two 240 shp (179 kW) Lycoming VO-435 engines for the US president. Two H-13J machines equipped with larger rotors and 225 shp (168 kH) Franklin 6VS-335 engines for test purposes were renamed H-13K. In 1962, the designations for US Army models H-13E, G, H, and K were prefixed with O (for ‘observation’). The designations for US Air Force H-13H and H-13J helicopters got a leading U (for ‘utility’). The three-seated OH-13S (replacing the OH-13H) and the double-seated instrument trainer TH-13T followed later. The US Navy first received 12 HTL-2 and nine HTL-3 helicopters, but the first significant version was the HTL-4, followed by the HTL-5 powered by a 0-335-5 engine. The HTL-6 trainers had the small flexible elevator. The HUL-1 was based aboard ice breakers.The latest model for the US Navy was the HTL-7. It was a double-seated instrument trainer with dual control and all-weather equipment.
In 1962, The HTL-4, -6, -7, and HUL-1 were renamed to TH-13L, TH-13M, TH-13N, and UH-13P. The Bell 47 was built under licence by Agusta in Italy, by Kawasaki in Japan, and by Westland in the UK, the latter being the 47G-2 for the British Army with the name Sioux. The various models served in more than 30 armies. There were a number of experimental versions. Perhaps the most significant examples were the Bell 201 (XH-13F) model and the Bell 207 Sioux Scout model. The Bell 201 had a Continental XT51-T-3 shaft turbine (a Turbomeca Artouste produced under licence). The Bell 207 was the first helicopter to be truely armed: With a 260 shp (194 kW) Avco Lycoming TVO-435-A1A turbocharger piston engine, a modified cabin with two tandem seats, small sponsons (with additional fuel) for relieving the main rotor and a remote-controlled barbette installed in the bow fitted with two 7.62 mm M60 MG’s, which were movable by 200° in horizontal direction and between -45° and +15° in vertical direction. Apart from military helicopter manufacturing by Bell as well as by licence manufacturers, civil helicopters were built for various applications. These included the Model 47B (the counterpart to the military YR-12/HTL-1) and the Model 47B-3 with an open cockpit for agricultural and other purposes. The subsequent Model 47D was the first helicopter to feature the ‘goldfish bowl’ canopy, and the Model 47D-1 from 1949 had the uncovered tail boom, similar to the H-13C.
The first significant modification was carried out with the Model 47G that combined the three seats of the 47D-1 with the 200 shp (149 kW) Franklin engine. The optional installation of the Avco Lycoming VO-435 with similar power led to the new designation Model 47G-2A, followed by the Model 47G-3A-1 with enlarged cabin, improved rotor blades and increased fuel capacity. Other powerplants included a Franklin 6VS-335-A with precompressor and 225 shp (168 kW) in the Model 47G-3, an Avco Lycoming TVO-435 with turbocharger and 280 shp (168 kW) in the Model 47G-3B, and Avco Lycoming VO-540 and VO-435 in the three-seated Models 47G-4 and 47G-5. A double-seated version of the latter model for agricultural purposes had the name Ag-5, and a civil version of the H-13J VIP transport helicopter of the USAF was called Model 47J Ranger. The Bell production of the Model 47 was discontinued at the end of 1973, with the 47G-5 being built last. Agusta in Italy and Kawasaki in Japan produced helicopters which were comparable with some of the civil versions of the Bell Model 47, but added some own versions as well. In addition, there were some specific helicopters modified by two leading American companies, i.e. the high-performance helicopter Carson Super C-4 and various El Tomcat agricultural machines developed by Continental Copters Inc. The US company Soloy produced helicopters with shaft turbines.
There are many Bell 47 still in use today.
Technical Data:
| Type designation: | Model 47G-5A |
| Usage: | Multi-purpose helicopter |
| Year of construction: | |
| Manufacturer: | Bell |
| Country: | USA |
| First flight: | ? |
| Length: | With rotor turning 13.30 m |
| Width: | |
| Height: | 2.84 m |
| Rotor diameter: | 11.32 m; tail rotor diameter 1.78 m, main rotor disc 100.62 m². |
| Number of rotor blades: | 2 |
| Powerplant: | Avco Lycoming VO-435-B1A piston engine |
| Power: | 265 shp (198 kW) |
| Max. speed: | On sea level 196 km/h, cruise speed 137 km/h |
| Service ceiling: | 3,200 m |
| Empty weight: | With equipment 786 kg |
| Max. take-off weight: | 1,293 kg |
| Range: | 412 km |
| Crew: | 1 |
| Passengers: | Depending on version |
| Armament: | Depending on version |
| Manufactured: | ? |
