Eurocopter says that its X3 hybrid has broken the unofficial helicopter speed record.

It attained a speed of 255 knots (472 km/hr) in level flight on June 7. Several days before this accomplishment, the X3 reached a speed of 263 knots (487 km/hr) during a descent.

Eurocopter says that the X3 achieved the 255-knot speed milestone while flying at an altitude of around 10,000 feet during a forty minute test flight over southern France near Istres. The aircraft is Eurocopter’s technology demonstrator for an advanced, cost-effective vertical takeoff and landing (VTOL) transportation system that offers the speed of a turboprop-powered aircraft and the full-flight capabilities of a helicopter.

“It’s no exaggeration to say that the X3 is clearly in its element at high speeds.” said Eurocopter test pilot Hervé Jammayrac. “While flying at both 255 knots and 263 knots, the X3 performed exactly as it has throughout its flight envelope, exhibiting outstanding stability and providing a low vibration level without any anti-vibration system.”

The X3 configuration utilises a pair of RTM 322 turboshaft engines to power a five-blade main rotor system with two propellers installed on short-span fixed wings. The RTM 322 variant, powering the X3, is based on the RTM 322 powering the NH90. It incorporates a FADEC adapted to the requirements of this high-speed demonstrator.

According to the company, this concept is suitable for missions requiring long transit flights at high speeds, while retaining full vertical lift and hover capabilities.

The X3 was developed in a rapid paced Eurocopter program that utilisd one of the company’s Dauphin helicopters as the airframe. For the latest high-speed milestone, the demonstrator was equipped with a drag-reducing rotor head fairing, which directly benefitted from company testing of a high-speed Dauphin DGV testbed during the 1990s, along with the addition of landing gear fairings. The Dauphin DGV enabled Eurocopter’s predecessor company Aerospatiale to set another helicopter speed milestone – reaching a record velocity of 200 knots in 1991.

Eurocopter flight test engineer Dominique Fournier – who was aboard the X3 with test pilot Jammayrac for the latest history-making flights – said the current high-speed evaluations are providing real data, in addition to the more symbolic aspect of achieving rotorcraft speed milestones.

“These flights allow us to further explore the behavior of main rotors at high speeds, and enable us to make effectiveness assessments of the fairing we’ve added to the main rotor hub – which will be beneficial for drag optimistion across Eurocopter’s overall product range,” Fournier explained. Photograph Copyright Eurocopter / A.Pecchi

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