Eurocopter AS-355 Ecureuil 2
Country of Origin
Twin engined light utility helicopter
The twin engined member of the Ecureuil (= Squirrel) family, the AS-355 Ecureuil 2 offers greater performance, carrying capability and the increased safety benefits of twin engines compared to the single engined AS-350. Development of the first twin engine Ecureuil began early in the model's development life, with the first flying on September 28 1979. This prototype was powered by two Allison 250-C20F turboshafts, supplying power to the main and tail rotors through a combining gearbox. Put into production as the AS-355E, it was essentially a twin engined version of the AS-350 with detail changes made to the fuselage structure, fuel system, transmission and main rotor blades to support the twin engine configuration. In common with the AS-350, the AS-355 features the maintenance free Starflex main rotor hub, while the main rotor blades are of composite construction. The AS-355F replaced the AS-355E from early 1982, and introduced new wider chord main rotor blades and a higher max takeoff weight. The AS-355F was followed by the AS-355F-1 in January 1984 and AS-355F-2 in December 1985, which introduced progressively higher maximum takeoff weights. The current production model is the AS-355N Ecureuil 2 which introduced twin Turbomeca TM-319 Arrius turboshafts. It was certificated in 1989 and first deliveries took place from early 1992. It is marketed in North America as the TwinStar. As with the single engined AS-550, the twin engine military AS-555 is marketed as the Fennec (the AS-555SN is fitted with a chin mounted search radar for ASW). Aerospatiale's helicopter division was integrated into Eurocopter in January 1992. The AS-355 is built under licence in Brazil as the Helibras HB-355 Esquilo.
AS-355F - Two 315kW (420shp) Allison 250-C20F turboshafts driving a three blade main rotor and two blade tail rotor. AS-355N - Two 302kW (406shp) max continuous rated Turboméca TM-319-1A Arrius turboshafts.
AS-355F - Max cruising speed 224km/h (121kt). Initial rate of climb 1280ft/min. Hovering ceiling in ground effect 5900ft. Service ceiling 11,150ft. Range with max fuel and no reserves 703km (380nm). AS-355N - Max cruising speed 222km/h (120kt), economical cruising speed 217km/h (117kt). Initial rate of climb 1260ft/min. Hovering ceiling out of ground effect 2460ft. Range with max fuel 722km (390nm).
AS-355F - Empty 1305kg (2877lb), max takeoff 2540kg (5600lb) or 2600kg (5732lb) with external sling load. AS-355N - Empty 1436kg (3166lb), max takeoff 2600kg (5732lb).
Main rotor diameter 10.69m (35ft 1in), length overall rotors turning 12.94m (42ft 6in), fuselage length 10.91m (35ft 10in), height 3.14m (10ft 4in). Main rotor disc area 89.8m2 (966.1sq ft).
Standard seating for six, including two forward seats and a four place rear bench seat. Can be configured for police, ambulance, EMS and media missions.
Orders for military AS-555s and civil AS-355s total over 880. Helibras of Brazil has built over 25 AS-355s under licence.
Eurocopter AS-355 Ecureuil 2
The backbone of this section is from the The International Directory of Civil Aircraft by Gerard Frawley and used with permission. To get your own copy of the book click here.