FORTY YEARS LATER, BORN OF THE FAMOUS ALOUETTE FAMILY, THE GAZELLE REPRESENTS THE NEW GENERATION OF VERY TECHNOLOGICALLY ADVANCED HELICOPTERS

 

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Built by Sud Aviation France (now part of the Airbus consortium) the Gazelle is considered by most to be a military machine and indeed, thousands have been sold as such around the world. A fair assumption - but for one forgotten fact. While producing thousands of helicopters for the military, Aerospatiale also found time to produce a few for direct sale to civilians. In military hands it has been used for training, air taxi and even battlefield support, and has performed exceptionally well in all of these roles.  In civilian hands it is an exceptional personal cross-country cruiser where it excels in speed and reduced pilot workload

 

In the mid-1950s, the French firm Sud Aviation - later Aerospatiale and now Airbus - scored a significant success in the helicopter business with the the highly successful SE 313B Alouette II light helicopter and its refined SE3160 (SA316a-c) Alouette III derivative. From the mid-1960s increasing thought was given to a follow-on to replace the Alouette II and III. One of the drivers for this effort were requirements from the French military for improved helicopters; the British military had similar requirements, and so in February 1967 Sud Aviation and Westland of the UK signed an agreement to collaborate on the development of helicopters for their military forces. This lead to to a rethink of the Alouette (Lark) design to come up with the modernized SA341 Gazelle light helicopter, which would also prove a major success.

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The Gazelle is clearly a descendant of the Alouette III, featuring a full fuselage, three-blade rotor, single turboshaft engine behind the rotor mast, and tailplane with tailfins on the end. The Gazelle is, however, effectively a new design, with little or no parts commonality with the Alouette III. The Gazelle is sleeker and much more modern in appearance, particularly with the fenestron tail fan. It abandoned the Alouette III's tricycle wheeled landing gear and reverted to landing skids. Wheels can be fitted to the skids for ground handling.

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The Gazelle can climb at a rate of 12.2m/s. The helicopter has a cruise speed of 264km/h and can fly at a maximum speed of 310km/h. The service ceiling of the Gazelle is 12,000ft. The maximum take-off weight is 1,900kg, while the endurance and range - in up to 30 Degree Centigrade, with pilot + 3 pax and full fuel (100 liters thereof for reserve purposes), within the IGE and OGE hovering envelope - 2.25 hrs and 270 nm!

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The French military SA341 F2 model Gazelles has the stronger Astazou III N2 turbine (480KW); a higher TBO of 2,750 hrs; the upgraded Fenestron and Main Rotor Heads - increasing the MAUW to 1,900 kg.

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"The origins of the Aerospatiale Gazelle goes back to the early 1960's when the Sud Aviation design team began to consider a replacement for the highly successful SE 313B Alouette II. Three years later, in 1963, the French and British Governments each had a requirement for Army light observation helicopters and, as part of a joint programme with Westland, work was started on the design that would eventually culminate in the Gazelle alongside the Lynx and Puma. All three types would serve in both the French and British armed Forces. The designers chose to utilize the well proven Alouette dynamic components and a 523 shp Turbomeca Astazou II engine and soon christened the four seat helicopter project the WS-22. The design, whilst an improvement on the Alouette II, still needed further refinements before being granted production go ahead. The British Army went on to order American Bell 47G Sioux helicopters, but Sud Aviation re-evaluated their design and brought in engineers from Bolkow of Germany to assist. Together they installed a new fibreglass rigid-rotor system and within weeks the new design had been re-christened as the X-300. The X-300 had a gross weight of 2,650lbs and a cruising speed of 124 knots. After discussing the project with potential customers, the design was refined to be able to undertake tasks such as light transport work, rescue, light attack plus casualty evacuation work. This last requirement set the parameters of the generous spacious cabin, which was to be able to accommodate a stretcher patient without difficulty. As a result the cabin can seat five in comfort.

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A number of powerplants were studied for possible use with the SA340, including the Allison T-63, Continental T65, Bristol/Siddeley/Turbomeca Oredon III, Pratt and Whitney PT68, AiResearch TSE331 and Turbomeca Astazon XIV, but the selected engine was the Turbomeca Astazov IIN.

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The Gazelle further matured in 1966 and introduced the then revolutionary 'fenestron' a multi-bladed small diameter fan mounted within the fin area. The Fenestron replaced the tail rotor and was expected to allow all the engine power to be concentrated on driving the main rotor during cruise flight.

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With a supply of Bell Sioux helicopters in service, the requirement for the British Army was only partially satisfied and there still existed a need for more light observation helicopters. The British Secretary of State for Defence, Denis Healey ,and the United Kingdom Minister of Aviation, John Stonehouse, arranged a meeting with their French counterpart Monseiur Messener, French Minister for the Armed Forces, to discuss mutual programs. The meeting was held in Paris on 16 January 1967 to discuss Anglo-French military aeronautical projects.

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The Memorandum of Understanding was to jointly develop and produce the SA 340, together with the Lynx and Puma. The following February saw the roll out of the SA 340 prototype (F-WOFH). This aircraft differed from production aircraft in that it had neither, the rigid Bolkow rotor or the fenestron. Instead the aircraft had a horizontal stabiliser and fins instead of the shrouded rotor. The SA 340 first took to flight at Marignane on April 7, 1967. Still the aircraft performed well in trials and established a number of type standards. The next aircraft to enter the trials program was F-ZWRA in April 1968. F-ZWRA had the rotor system and the fenestron, but it was soon established that much work was needed on the type. The decision was taken to replace the rigid rotor system with a semi-articulated the rotorhead matched to fibreglass blades.

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With these modifications undertaken the design was again re-designated as the SA 341 and, in July 1969, the name Gazelle was chosen for the helicopter to properly describe its agility and speed. Four SA 341 prototypes were built, and the third of these (F-ZWRI/XW 276) was transferred to Westland in August 1969 to act as the British Army trials aircraft.

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110 aircraft were authorized in July 1970 by the French and British Governments to meet initial ALAT and British Army needs. The first production aircraft made its initial flight at Marignane on 6 August 1971. The flight was marred somewhat by excessive vibration and ground resonance problems and further production was slowed until the difficulties were rectified. Technicians worked hard to find a solution and by May 1972 with modifications made to the gearbox and main rotor blades production was resumed at full rate.

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Having entered service in both Britain and France, Aerospatiale continued to refine and develop the design. In the summer of 1977 the company conducted a series of trials, the first with the Gazelle prototype SA-3492 and then with a production Gazelle modified and called SA-349-2. With an Astazov 14 engine and stronger transmission, this machine reached speeds of around 300km/hr (186 mph). Around the same time Aerospatiale experimented with fitting small wings to explore high manoeuvrability. The wing has a 'zero' profile of about 12 percent thickness and carries ailerons and spoilers.

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FRENCH GAZELLE'S

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In France, the first SA 341F's for the ALAT were delivered in early 1973. The fourth unit was subsequently handed over for trials with the HOT anti-tank missile. The trials were successful and culminated in certification for the carriage of four missiles. The concurrent development of an uprated 870shp Astazou XIVH engine by Turbomeca allowed an increase in payload. With the new engine and weapons the type was designated as the SA-342K and garnered interest from the Middle East countries such as Egypt and Iraq. The French also uprated 110 of their SA-341F's to the new standard and were re-designated as SA-342M's.

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Kuwait also bought twenty of the new anti-tank variant and was the first customers to receive new build aircraft in April 1975. The previous year a license agreement with the then Yugoslavia was signed for the construction in that country of 132 SA-341H with assistance from Aerospatiale. 1982 saw new production commence in France of 60 SA-342K's for Egypt, plus another 30 were built locally in Egypt at a factory in Helwan. The Egyptian's also secured the right to market the aircraft in the Middle East.

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By 1985 total Gazelle production had comfortably passed the 1,000 mark and orders had reached 1,146. These figures included 298 aircraft for the ALAT, 67 for the Syrian Air Force and 122 built under licence in Yugoslavia. The type also found a home in the United States where sales were steady, if not spectacular, being sold through Vought Helicopters International. In all, the Gazelle family is currently operational with some 19 military and para-military services. Gazelles' serve in the following countries: Angola, Burundi, Cameroon, Chad, Cyprus, Ecuador, Egypt, France, Gabon, Iraq, Kenya, Kuwait, Lebanon, Morocco, People's Republic of China, Qatar, Rwanda, Senegal, Syria, UK and the former Yugoslavia, United Arab Emirates,Ireland."

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BRITISH GAZELLES

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Westland in Yoevilton started construction of the first of three types of the Gazelle in 1972. The three Armed Services each received a different aircraft specification; the Army received the SA 341B, the Royal Navy SA 341C and the RAF the SA 341D. Initially, however, a joint trials unit for all three services was established with trials starting on 3 May 1973. Six and a half months of intensive flying in Gazelles ended in late November 1973 at the British Army Aviation Centre, Middle Wallop. Four aircraft took part in the Intensive Flying Trials Flight Programme and logged some 2,400 flying hours, the equivalent of two and half years flying in six months. Three were Mk1 Gazelles of the Army and one was a Mk2 of the Royal Navy. Nine pilots from all three services flew the aircraft in daylight hours five days a week throughout the trials. Poor panel lighting in the cockpit resulted in a temporary night time ban until improvements were made.

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As production increased at Westland, so more of the Gazelle's found their way to frontline service with the British Army's Army Air Corps and replaced the Bell 47G Sioux in operational service. It wasn't just the Armed Forces, however, that were attracted to the light observation helicopter. Many British private customers bought the civilian version, these included Point to Point, Christian Salveson, Orme Developments, Bouley Investments, McAlpine Aviation, Broseley Investments, Rogers Aviation and Twyford Moors. Production of the Gazelle in all forms continued at Westland until January 1984 when the 281st example of the type left the production line.

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The Royal Navy accepted its first aircraft XW845 in July 1972. Almost two years later in December 1974 the type entered squadron service with No 705 squadron at RNAS Culdrose. The Gazelles replaced aging Whirlwind and Hiller HT Mk 2's in service. For a while, before defense cuts began to bite, the Gazelles of this squadron performed at air shows as 'The Sharks'.

The Gazelle first went to war in the Falklands in 1982 and subsequently served in an operational role in Kosova and Kuwait in the first Gulf War. In 1991, during the first Gulf War, saw Gazelle's deployed with the Army Air Corps and Royal Marines fitted with two 7.62mm L20A1 machine-guns and reconnaissance flares. Their principal duty being scouting for the armoured attacks and the Lynxes. The most recent Iraqi conflict saw Gazelle's fitted with laser target designators with which they identified targets such as T-55 tanks for Lynx helicopters armed with anti armour weapons. The Gazelles of 847 NAS identified all but one of the T-55 tanks destroyed by the Lynx's. In the summer of 2005 the Gazelle's of 847 NAS fell victim to defence cuts and were withdrawn from service.

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The Royal Air Force operates four Gazelle's RAF Leuchars by 3 Flight Army Air Corps. 3 Flight AAC (Volunteer) is based in the old Air Traffic Control building and is a detached command whose headquarters are at Netheravon, Wiltshire. The unit is tasked by the Joint Helicopter Command in support of Land Command. Currently their helicopters carry out liaison, VIP duties, reconnaissance, photographic, load carrying and command and control duties in support of Army units in Scotland.

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- Patrick Bonifice -