|Eurocopter X³ in flight|
|Role||Experimental compound helicopter|
|First flight||6 September 2010|
|Developed from||Eurocopter EC155|
The Eurocopter X³ (X-Cubed) is an experimental high-speed compound helicopter developed by Eurocopter (now Airbus Helicopters). A technology demonstration platform for Eurocopter "high-speed, long-range hybrid helicopter" or H³ concept, the X³ achieved 255 knots in level flight on 7 June 2013, setting an unofficial speed record for a helicopter.
Design and development
The X³ demonstrator is based on the Eurocopter AS365 Dauphin helicopter, with the addition of short span wings each fitted with a tractor propeller. 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.
Conventional helicopters use tail rotors to counter the torque effect of the main rotor. The starboard propeller of the X³ has a higher rotational speed than the port to counter the torque effect. The X³ can hover with a pitch attitude between minus 10 and plus 15 degrees. It can bank 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/Airbus Helicopters has 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 sees the offshore oil market and Search and rescue community as potential customers for X³ technology. An X³-based compound helicopter called LifeCraft is also one of two high-speed rotorcraft flight demonstrators planned under the European Union's Clean Sky 2 research program being proposed to the European Commission.
|This aircraft article is missing some (or all) of its specifications. If you have a source, you can help Wikipedia by adding them.|
Data from FlightGlobal; no other specifications have been released by Eurocopter.
- 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: 2-bladed five-bladed tractor propellers gear driven from main engines.
- Maximum speed: 472 km/h; 293 mph (255 kn) at roughly 10,000 ft (3,048 m)
- Cruising speed: 407 km/h (253 mph; 220 kn) 
- Service ceiling: 3,810 m (12,500 ft)
- Rate of climb: 28 m/s (5,500 ft/min) 
- Related development
- Aircraft of comparable role, configuration and era
- Bell 533
- Carter Personal Air Vehicle
- Fairey Rotodyne
- Kamov Ka-92
- Mil Mi-X1
- Piasecki X-49
- Sikorsky X2
- Related lists
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- "L’Hélicoptère de démonstration X³ atteint les 430km/h !" [The demonstration helicopter X³ reaches 430 km/h!]. Avia News (in French). 24 Heures.
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- Warwick, Graham. "EADS Withdraws JMR Bid To Focus On AAS" Aviation Week & Space Technology, 4 June 2013. Accessed: 17 June 2014. Archive
- "EADS Quits Helo Competition To Pursue Uncertain AAS" Aviation Week & Space Technology, 10 June 2013. Accessed: 17 June 2014. Archive
- US Army selects Bell, Sikorsky/Boeing team for JMR demonstration, Flight global.
- McLeary, Paul. "Outgoing General: US Army Must Continue To Fund Research and Development" DefenseNews, 14 January 2014. Accessed: 17 June 2014.
- A Preliminary Programme Outline For Clean Sky 2 (PDF), EU: Clean sky, July 2012 . Size 2 MB.
- Airbus Helicopters X³ makes its new home at France's national Air and Space museum (press release), Airbus, 19 June 2014, archived from the original on 2014 Jun 19, retrieved 19 June 2014 .
- Croft, John (23 February 2009). "Heli-expo 2009: Rolls-Royce confirms role in Eurocopter X³ programme". Flight Global. Retrieved 28 September 2010.
- "The RTM322 shared a speed record with X³", Le Bourget, Safran.
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- Dubois, Thierry (August 2011), "Eurocopter Launches Dauphin Replacement; Preps for X³", Aviation Today, retrieved 31 March 2012 .
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|Wikimedia Commons has media related to Eurocopter X3.|
- X3, Eurocopter.
- Pictures: Eurocopter unveils high-speed hybrid helicopter, Flight global, 2010 Sep 27 .
- Eurocopter unveils new-look helicopter, Yahoo, 2010 Sep 27 .
- 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.