SA315 Alouette II

The Aérospatiale Alouette II (company designations SE 313 and SA 318) is a French light utility helicopter built by Sud Aviation and later Aérospatiale. It was the first conventional production helicopter powered by a gas turbine rather than a piston engine, with the first production example completed in April 1956. Military operators used it for observation, photography, air-sea rescue, liaison and training, while civil roles included medical evacuation with two external stretcher panniers, crop-spraying and flying-crane work with a 500 kg underslung load. More than 1,300 were built between 1956 and 1975, and the type served with over 80 countries and 47 armed forces.

Development

After the SE 3120 Alouette set helicopter speed and distance records in July 1953 but proved too complex to market, the French government backed further work on condition that a helicopter reach production within two years. SNCASE prepared seven turboshaft-powered designs, X.310A to X.310G; the X.310G was selected and paired with an improved Turbomeca Artouste, a 260 hp single-shaft turbine developed by Joseph Szydlowski from his Orédon engine. The prototype SE 3130 flew on 12 March 1955, and on 6 June a pre-production aircraft flown by Jean Boulet set an altitude record of 8,209 m. Boulet retook the record on 13 June 1958 at 10,984 m. A French certificate of airworthiness followed on 2 May 1957. The SA 3180 Alouette II Astazou, using the Turbomeca Astazou IIA, was introduced in 1964. Production ended in 1975, the type having been displaced by the SA 315B Lama and the Alouette III. Licence production took place in Brazil, Sweden, India and the United States.

Design

The SE 313B is powered by a single Turbomeca Artouste IIC6 turboshaft of 400 kW derated to 269 kW. Main rotor speed is held by an automatic fuel governor, dispensing with a twist-grip throttle and the conventional throttle-to-collective linkage; a single lever regulates collective pitch and actuates the governor. No clutch is fitted, simplifying the transmission. The cabin seats up to five including the pilot, with side-hinged doors and a dome windscreen. Skids, wheels or pontoons could be fitted. Maximum speed is 185 km/h, range 565 km with maximum fuel, endurance 4.1 hours and service ceiling 2,300 m. Maintenance demands were high: the main rotorhead alone carried 20 grease nipples requiring re-lubrication every five flight hours, and rectangular sand filters often had to be cleaned after each landing.

Armament

The Alouette II was the first helicopter fitted with anti-tank missiles, carrying the Nord AS.11 MCLOS wire-guided weapon. French Army aircraft also mounted machine guns, and French Navy examples carried homing torpedoes for anti-submarine work. Gunship conversions were typically armed with Nord Aviation SS.10 or SS.11 missiles.

Operational History

On 3 July 1956 an Alouette II carried out the first helicopter mountain rescue, evacuating a mountaineer from above 4,000 m, and on 3 January 1957 recovered the crew of a Sikorsky S-58 downed on Mont Blanc. First deliveries to the French Army came in 1957, followed by orders from the United Kingdom, West Germany and Austria. The type saw heavy use in the Algerian War, lifting up to four equipped soldiers. Rhodesia operated it with the Army and British South Africa Police in reconnaissance, casualty evacuation, supply and communications-relay roles, modifying the fleet's refuelling equipment, gun sights, cabin fittings, armour and armament, and using it as a core element of Fireforce operations based at Centenary and Mount Darwin. Fuel caches were dispersed across the country to offset its limited range. The French Army replaced its fleet with the AS350 Écureuil. In July 2018 a hijacked Alouette II was used in the escape of Rédoine Faïd from Réau prison.

Variants

• SE 3130 Alouette II: Initial version with Turbomeca Artouste II, 300 kW for takeoff, 1,500 kg maximum weight.
• SE 313B Alouette II: Artouste IIC5 or IIC6 engine with maximum weight raised to 1,600 kg.
• SE 3131 Gouverneur: Executive version with enclosed tailboom, abandoned in favour of the Alouette III.
• SA 318C Alouette II Astazou: Astazou-powered variant with maximum weight raised to 1,650 kg.
• SA 315B Lama: Built for an Indian "hot and high" requirement, combining the Alouette III powerplant and rotor system with a reinforced Alouette II airframe; in service from July 1971.