Second X3 test phase set for launch

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Eurocopter's push for a new era of rotorcraft speed resumes this month when a new flight-testing of its X3 gets under way after a three-month upgrade.

The radical hybrid concept demonstrator, which has a five-blade main rotor for vertical lift but gets its forward thrust from single propellers mounted to short-fixed wings either side of the fuselage, first flew on 6 September 2010. In December it attained a true airspeed of 180kt (333km/h) in level flight. That first test phase also achieved an altitude of 12,500ft (3,810m) and performed manoeuvres at bank angles of up to 60°. Testing at Eurocopter's Marignane base will be aimed at sustained cruise speeds of 220kt, slower than promised by Sikorsky's X2 but Eurocopter boss Lutz Berling is confident the X3 will win a "race for productivity" by offering "cost-effective speed". The aircraft, a demonstrator for a concept entitled H3 (high-speed hybrid helicopter), illustrates the Eurocopter approach to the civil market. As Bertling puts it, Eurocopter does not sell helicopters - it sells mission capability. With H3, it aims to offer a high-speed alternative to traditional rotorcraft. Eurocopter hopes to introduce the technology on most new models as an option to standard lift on otherwise similar machines. The first use of X3 technology, which could add about a quarter to acquisition cost, should be in six years as a replacement for the EC225 Super Puma.

 © Eurocopter
New flight-testing of Eurocopter's X3 gets under way this month

The X3 was designed to keep development costs down. Eurocopter adapted existing components, including the airframe (from the Dauphin 365), main rotor (EC155) and main gearbox module (EC175). Engines are Rolls-Royce Turbomeca RTM322s, the smallest certificated and off-the-shelf available units comfortably in the required power range. The main rotor provides lift only. Forward thrust - and anti-rotation torque - are provided by the side propellers. These are shaft driven from the main engines and can be declutched while loading and unloading the aircraft. Later models will dispense with the side propellers' independent speed control if variable pitch proves adequate for anti-torque. At high speed, anti-torque is provided by the tail fins.

The short-fixed wings supporting the side propellers provide enough lift at speed to support 30-40% of the aircraft's mass, allowing the main rotor to be slowed by 15-20% at speeds greater than 160kt, greatly reducing drag.

For Eurocopter, other 2011 highlights are expected to include the launch of the X4, a "game changing" successor to the 365 Dauphin, as well as the first flight of a new version of an existing, but unspecified, model.

Eurocopter will also validate the first use of diesel engines in light helicopters. A new EC225 simulation training facility opened in February 2011 in Aberdeen and new simulators are being installed in Brazil, China, Malaysia and Singapore. In addition, MRO joint ventures in Malaysia and Kazakhstan will be implemented this year. The company also hopes for a 2013 move of its main blade plant from La Courneuve, near Paris, to new premises in Dugny, near Le Bourget, at a former French armed forces facility.