Aérospatiale AS355 Écureuil 2

1st Flight 1979

                                                 Military Users-

Algerian Air Force, Argentine Naval Prefecture, Austrian Federal Police, Belarus Border Guard, Brazilian Air Force, Brazilian Navy, Royal Cambodian Air Force, Djibouti Air Force, Jamaica Defense Force, Malawi Air Wing, National Navy of Uruguay, Bophuthatswana Air Force, Garda Air Support Unit.

AS355 Écureuil 2

During the early 1970s, Aérospatiale initiated a development program to produce a replacement for the aging Aérospatiale Alouette II.

While the Aérospatiale Gazelle, which had been developed in the 1960s and 1970s, had been met with numerous orders by military customers, commercial sales of the type had been less than anticipated, thus the need for a civil-oriented development was identified.

The development of the new rotorcraft, which was headed by Chief Engineer René Mouille, was focused on the production of an economic and cost-effective aerial vehicle, thus both Aérospatiale’s Production and Procurement departments were heavily involved in the design process.

AS355 Écureuil 2

One such measure was the use of a rolled sheet structure, a manufacturing technique adapted from the automotive industry, another innovation was the newly developed Starflex main rotor.

It was also decided that both civil and military variants of the emergent helicopter would be developed to conform with established military requirements.

On 27 June 1974, the first prototype, an AS350C powered by a Lycoming LTS101 turboshaft engine, conducted its maiden flight at Marignane, France; the second prototype, powered by a Turbomeca Arriel 1A, following on 14 February 1975.

AS355 Écureuil 2

On 28 September 1979, a twin-engined version of the rotorcraft made its first flight, it was subsequently released and marketed under the names Écureuil 2, Twin Squirrel, and in North America TwinStar.

It was not long before overseas production of the type commenced.

The Brazilian helicopter manufacturer Helibras’ most numerous product in its lineup has been the Eurocopter AS350 Écureuil.

The company had license-assembled both the AS350 and AS355 from kits shipped from Eurocopter main production line for the family in Marignane, France; Brazilian AS355s contain a level of indigenously-developed content as well.

AS355 Écureuil 2

During the 2000s, Eurocopter was reportedly in talks to open up an additional AS355 production line in China.

Despite the introduction of the Eurocopter EC130 in 2001, production of both the AS350 and AS355, and of their AS550 and AS555 Fennec militarized counterparts, was continued for some time.

During 2007, the more capable AS355 NP variant, which was powered by Full Authority Digital Engine Control (FADEC) engines, was introduced to service.

AS355 Écureuil 2

According to aerospace periodical Flight International, the decision to develop the AS355 NP, which Eurocopter stated was aimed at the corporate transport and utility operators, had been the firm’s response to American competitor Bell Helicopter’s launch of the Bell 417.

In addition to Eurocopter’s internal efforts to enhance the Écureuil 2, third parties developed their own modifications and upgrades specifically for the type.

Conversion programs and add-ons for the AS350 family have been produced and are offered by numerous ‘aftermarket’ specialists, many upgrade and refit programs have involved the increasing use of digital systems, such as the Garmin-built G500H avionics suite.

AS355 Écureuil 2

During September 2015, Airbus Helicopters announced that the company had decided to terminate the manufacture of the AS355 as part of an effort to focus on stronger-selling rotorcraft.

Production of the AS355 continued through 2016 until the existing order backlog had been fulfilled.

Despite the termination of the AS355 programme, production of its AS350 siblings has continued and even been expanded around the same timeframe.

AS355 Écureuil 2

Specifications-

Crew: 1

Capacity: 6

Length: 12.94 m (42 ft 5 in) inc. main and tail rotors

10.93 m (36 ft) fuselage and tail rotor only

Height: 3.14 m (10 ft 4 in)

Empty weight: 1,305 kg (2,877 lb)

Max take off weight: 2,540 kg (5,600 lb) internal load

2,600 kg (5,732 lb) with max. slung load

Fuel capacity: 730 l (190 US gal; 160 imp gal) usable, in two tanks

Power plant: 2 × Allison 250-C20F turbo shaft engines, 313 kW (420 hp) each

Main rotor diameter: 10.69 m (35 ft 1 in)

Main rotor area: 89.75 m2 (966.1 sq ft)

Blade aerofoil section: ONERA OA211 : root; ONERA OA209/OA207 : tip

Performance

Cruise speed: 224 km/h (139 mph, 121 kn) (max cruise)

Never exceed speed: 278 km/h (173 mph, 150 kn)

Range: 703 km (437 mi, 380 nmi) with max fuel no reserve

Service ceiling: 3,400 m (11,200 ft)

Rate of climb: 6.5 m/s (1,280 ft/min)

AS355 Écureuil 2

Credits-

Aeroscopia Museum, Toulouse, France

Helicopters: An Illustrated History of Their Impact-Stanley McGowen

Jane’s pocket guide: Modern military helicopters- Tim Ripley

Wikipedia.

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