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Aérospatiale Alouette III

Light helicopter family by Sud Aviation, later Aerospatiale

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Through Cannon and Himalayas

The Alouette III was developed as an enlarged derivative of the earlier successful Alouette II. It shared many design elements with its predecessor while offering an extra pair of seats and other refinements. It quickly became a commercial success and was operated by a range of civil and military customers. Further variants were also developed; amongst these was a high-altitude derivative, designated as the SA 315B Lama, which entered operational service during July 1971. The Alouette III was principally manufactured by Aérospatiale, after its take over of Sud Aviation in 1970. The type was also built by various licensed manufacturers such as Hindustan Aeronautics Limited in India (as HAL Chetak), by Industria Aeronautică Română in Romania (as IAR 316), and by Eidgenössisches Flugzeugwerk in Switzerland (as F+W Emmen).

Similar to the Alouette II, in military service, it was used to perform missions such as aerial observation and photography, air-sea rescue, communication liaison, transport, and training. It could also be armed with anti-tank missiles, anti-ship torpedoes, and a fixed cannon. In a civilian capacity, the helicopter was commonly used for casualty evacuation (often fitted with a pair of external stretcher panniers), crop spraying, personnel transportation, and for carrying other external loads.

By the 2010s, many operators were in the process of drawing down their fleets and replacing them with more modern types; the French Armed Forces intended to replace their Alouette IIIs with the newly developed Airbus Helicopters H160 and the Indian Armed Forces with the HAL Dhruvs.

Development

Origins

The Alouette III has its origins with an earlier helicopter design by French aircraft manufacturer Sud-Est, the SE 3120 Alouette, which, while breaking several helicopter speed and distance records in July 1953, was deemed to have been too complex to be realistic commercial product. Having received financial backing from the French government, which had taken an official interest in the venture, the earlier design was used as a starting point for a new rotorcraft that would harness the newly developed turboshaft engine; only a few years prior, Joseph Szydlowski, the founder of Turbomeca, had successfully managed to develop the Artouste, a 260 hp (190 kW) single shaft turbine engine derived from his Orédon turbine engine. An improved version of this engine was combined with the revised design to quickly produce a new helicopter, initially known as the SE 3130 Alouette II.

During April 1956, the first production Alouette II was completed, becoming the first production turbine-powered helicopter in the world. The innovative light helicopter soon broke several world records and became a commercial success. As a result of the huge demand for the Alouette II, manufacturer Sud Aviation took a great interest in the development of derivatives, as well as the more general ambition of embarking on further advancement in the field of rotorcraft.

In accordance with these goals, the company decided to commit itself to a new development programme with the aim of developing a more powerful helicopter that would be capable of accommodating up to 7 seats or a pair of stretchers. The design team was managed by French aerospace engineer René Mouille. The design produced, designated as the "SE 3160", featured several improvements over the Alouette II; efforts were made to provide for a higher level of external visibility for the pilot as well as for greater aerodynamic efficiency via the adoption of a highly streamlined exterior.

Into flight and production

On 28 February 1959, the first prototype SE 3160 performed its maiden flight, piloted by French aviator Jean Boulet. Shortly thereafter, the SE 3160 would become more commonly known as the Alouette III. During its flight test programme, the prototype demonstrated its high altitude capabilities on several occasions; in June 1959, it landed at an altitude of over 4,000 metres in the Mont Blanc mountain range and, during October 1960, it was able to achieve the same feat at an altitude more than 6,000 metres in the Himalayas. During these attempts, it was flown by Jean Boulet, who was accompanied by a pair of passengers and 250 kg of equipment.

During 1961, the initial SE 3160 model of the type entered serial production. On 15 December 1961, the Alouette III received its airworthiness certificate, clearing it to enter operational service. Despite an order placed by the French Army for an initial batch of 50 Alouette IIIs during June 1961, the first two customers of the rotorcraft were in fact export sales, having been sold outside of France. The Alouette III was specifically designed to fly at high altitudes, as such, it quickly earned a reputation for its favourable characteristics during rescue operations. According to its manufacturer, it was the first helicopter to present an effective multi-mission capability and performance to match with its diverse mission range in both civil or military circles.

The SE 3160 model continued to be produced until 1968, when it was replaced by the refined "SA 316B" model. (After its production ended, the SE 3160 has sometimes been retroactively redesignated "SA 316A", but its original SE 3160 designation is more commonly used, especially in older sources.) Both the SE 3160 and the SA 316B were powered by a more powerful version of the Artouste engine, the Artouste IIIB, whose turbine was rated to produce 858 horsepower (640 kW), though because of the limits of the engine's reduction gearbox, the Artouste IIIB was de-rated to generate 563 horsepower (420 kW) in service. The later "SA 319B" variant adopted the more fuel-efficient Turbomeca Astazou XIVB engine, extending its range and endurance; on 10 July 1967, the Astazou-powered Alouette III performed its first flight. During 1979, the 1,437th Alouette III departed from the company's assembly line in Marignane, France, after which the main production line was closed down as a consequence of diminishing demand for the type. During 1985, the final French-produced Alouette III was delivered. It had been produced from 1961 to 1985 in France, however, license production continued.

Overseas production

Despite the closure of Aérospatiale 's own production line, the event was not the end of the type's manufacturing activity. Over 500 Alouette IIIs are recorded as having been manufactured under licence abroad in several countries, such as Romania, India, and Switzerland. Various versions of the Alouette III were also either licence-built or otherwise assembled by IAR in Romania (as the IAR 316), F+W Emmen (de) in Switzerland, by Fokker and Lichtwerk in the Netherlands, and in India as the HAL Chetak. The Romanian IAR 316, was an Aérospatiale SA 316B Alouette III license produced from 1971 to 1987, with 250 made with about half for Romania and half for export. Additionally, Romania also developed the IAR 317 Airfox, an attack helicopter version of the IAR 316;at least one prototype was made and was debuted at the 1985 Paris Air Show.

Hindustan Aeronautics Limited (HAL) obtained a licence to construct the Alouette III, which was known locally as the Chetak, at their own production facilities in India. More than 300 units were built by HAL; the company has continued to independently update and indigenise the helicopter over the decades. A modernised variant of the Chetak has remained production, though at a diminished volume, into the 21st century. The latest HAL Chetak was delivered in 2021, and also included updated avionics. Over 350 Chetak had been produced the 2020s.

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