The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Airbus Helicopters. A technology demonstration platform for "high-speed, long-range hybrid helicopter" or H³ concept, the X³ achieved 255 knots (472 km/h; 293 mph) in level flight on 7 June 2013, setting an unofficial helicopter speed record.
|Airbus Helicopters X³ in flight|
|Role||Experimental compound helicopter|
|First flight||6 September 2010|
|Developed from||Airbus Helicopters AS365 Dauphin
Airbus Helicopters H155
Design and developmentEdit
The X³ demonstrator is based on the Eurocopter AS365 Dauphin helicopter, with the addition of short span wings each fitted with a tractor propeller, having different pitch to counter the torque effect of the main rotor. Conventional helicopters use tail rotors to counter the torque effect. The tractor propellers are gear driven from the two main turboshaft engines which also drive the five-bladed main rotor system, taken from an Eurocopter EC155.
Guest pilots describe the X³ flight as smooth, but the X³ does not have passive or active anti-vibration systems and can fly without stability augmentation systems, unlike the Sikorsky X2. The helicopter is designed to prove the concept of a high-speed helicopter which depends on slowing the rotor speed (by 15%) to avoid drag from the advancing blade tip, and to avoid retreating blade stall by unloading the rotor while a small wing provides 40–80% lift instead. The X³ can hover with a pitch attitude between minus 10 and plus 15 degrees. Its bank range is 40 degrees in hover, and is capable of flying at bank angles of 120 to 140 degrees. During testing the aircraft demonstrated a rate of climb of 5,500 feet per minute and high-G turn rates of 2Gs at 210 knots.
Eurocopter demonstrated the X³ in the United States during the summer of 2012, the aircraft logging 55 flight hours, with a number of commercial and military operators being given the opportunity to fly the aircraft.
With an aerodynamic fairing installed on the rotor head, the X³ demonstrated a speed of 255 knots (293 mph; 472 km/h) in level flight and 263 knots (303 mph; 487 km/h) in a shallow dive on 7 June 2013, beating the Sikorsky X2's unofficial record set in September 2010, and thus becoming the world's fastest non-jet augmented compound helicopter.
Eurocopter suggested that a production H³ application could appear as soon as 2020. The company had also previously expressed an interest in offering an H³ technology based solution for the United States' Future Vertical Lift program, with EADS North America submitting bid to build a technology demonstrator under the US Army's Joint Multi Role (JMR) program, but later withdrew due to cost and because Eurocopter might have to transfer X³ intellectual property to the US, and Eurocopter chose to focus on the Armed Aerial Scout instead. Ultimately the company was not downselected for the JMR effort, and the AAS program was cancelled.
Eurocopter saw the offshore oil market and Search and rescue community as potential customers for X³ technology. An X³-based unpressurised compound helicopter called LifeRCraft is also among the projects planned under the European Union's €4 billion ($5.44 billion) Clean Sky 2 research program as one of two high-speed rotorcraft flight demonstrators. Airbus began development of the hybrid composite helicopter with a 4.6-litre V-8 piston engine in 2014, froze the design in 2016 to start building in 2017, and plans to fly it in 2019.
On 20 June 2017 at the Paris air show, Airbus Helicopters revealed a high-speed demonstrator configuration based on the X3 called Racer for Rapid And Cost-Effective Rotorcraft. Developed within the Clean Sky 2 research programme, final assembly will start in 2019 for a 2020 first flight. Optimised for a cruise over 400 km/h (220 kn), 50% faster than a conventional helicopter, it will consume 15% less fuel per distance at 180 kn (330 km/h) than an helicopter at 130 kn (240 km/h), and aim for a 25% cost reduction per distance.
The lateral pusher propellers generate thrust and are isolated from passenger during ground operations by the box wings providing lift in cruise. Driven by two RTM322 engines capable of shutting down and restarting one inflight to save fuel and increase range, it will have a low weight and low maintenance hybrid metallic-composite airframe and lower weight high voltage direct current electrical generation.
Data from FlightGlobal
- Crew: 2
- Gross weight: 5,200 kg (11,464 lb) 
- Powerplant: 2 × Rolls-Royce Turbomeca RTM322-01/9a turboshaft engines, 1,693 kW (2,270 hp) each
- Main rotor diameter: 12.6 m (41 ft 4 in)
- Main rotor area: 124.7 m2 (1,342 sq ft)
- Propellers: 5-bladed (two tractor propellers gear driven from main engines).
- Related development
- Aircraft of comparable role, configuration and era
- Related lists
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design was frozen last summer ahead of its construction phase starting this year. Clean Sky 2 rotorcraft is classified as a hybrid helicopter.
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|Wikimedia Commons has media related to Eurocopter X3.|
- X3, Eurocopter, archived from the original on 30 September 2010.
- Pictures: Eurocopter unveils high-speed hybrid helicopter, Flightglobal, 27 September 2010.
- Eurocopter unveils new-look helicopter, Reuters, 27 September 2010.
- Eurocopter High-speed, long-range Hybrid Helicopter H3 Demonstrator Makes First Flight, Deagel.
- Video X³
- Video X³, Cockpit
- Making of
- Ferrier, Jean-Jacques, Hybrid helicopter (patent), Eurocopter, US 8070089 B2.