June 17, 2013
Eurocopter's X3 has claimed the unofficial helicopter speed record from Sikorsky's X2, achieving 255 kt. in level flight and 263 kt. in a dive, and raising the question of what comes next for the European manufacturer's high-speed rotorcraft concept.
In flights at the Istres test base near Marseille, France, in early June the X3 experimental compound helicopter beat its previous top speed of 232 kt. set in May 2011. The new round of high-speed trials follows a lay-up during which the aircraft's gearbox was tweaked to operate at the full power level provided by its two Turbomeca RTM322 turboshafts.
The X3 also was fitted with an aerodynamic fairing around the rotor head to reduce its parasitic drag. The company says test data related to installation of the fairing will be “beneficial for drag optimization across Eurocopter's overall product range.” The X3 has now flown a total of 140 hr. since its maiden flight in September 2010. The company is understood to be planning to retire the X3 toward the end of the year, the aircraft having generated more data on high-speed rotary-wing flight than was originally envisaged.
Sikorsky's rigid coaxial-rotor X2 technology demonstrator achieved 253 kt. in level flight and 262 kt. in a dive in September 2010. The aircraft was retired in July 2011 after logging 22 flight hours, and Sikorsky began development of the 220-kt. S-97 Raider light tactical helicopter. The first of two industry-funded prototypes is scheduled to fly at the end of 2014.
Subsequently, Sikorsky teamed with Boeing for the U.S. Army's planned Future Vertical Lift Medium program to replace the UH-60 Black Hawk beginning in the mid-2030s. The team has been selected to build a 230-kt. compound helicopter demonstrator based on the X2 configuration. The aircraft is planned to fly in 2017 under the Army's Joint Multi-Role (JMR) technology demonstration program.
Eurocopter was expected to propose an X3-configuration demonstrator for JMR, but EADS North America withdrew its bid to focus company resources on the Army's Armed Aerial Scout requirement (AW&ST June 10, p. 31). This raises the question of what the company has planned for the technology.
Eurocopter may now see the X3 as having wider applications in commercial and civilian government roles. Interestingly the company highlights civil missions over military applications, with long-distance search-and-rescue, offshore airlift and passenger transport, along with inter-city shuttle services, suggested as possible roles.