Eurocopter X3 (X Cubed)
The X3 experiment did not lead to a commercial proposal on the part of the manufacturer, contrary to its initial declarations. Airbus Helicopters pursued the X3 development as part of self-funded company efforts to evolve rotorcraft that offer new ways to perform missions, fly faster and farther, and reduce operating and maintenance costs. The X3, known as a hybrid helicopter, demonstrated the company’s long-range, High-speed Hybrid Helicopter (H3) concept. From its maiden take-off in September 2010 to its retirement in 2013, the X3 fully validated Airbus Helicopters’ hybrid concept, using a pair of turboshaft engines to power both a five-blade helicopter main rotor and two propellers installed on short-span fixed wings.
The Eurocopter X3 hybrid helicopter opened the frontiers of aviation by attaining a speed milestone of 255 knots (472 km/hr) in level flight on 07 June 2013. Several days before this accomplishment, the X3 reached a speed of 263 knots (487 km/hr) during a descent. With these two successes, the X3 surpassed the unofficial speed record for a helicopter.
Eurocopter achieved the historic 255-knot speed milestone with the X3 flying at an altitude of around 10,000 feet during a 40 minute test flight over southern France near Istres. It marked the latest in a growing list of achievements for the X3, which 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.”
During more than 155 hours logged by the aircraft in 199 flights, milestones achieved included a level flight speed of 255 knots (472 km/hr) on June 7, 2013 – surpassing previous high speeds reached by a helicopter. While exploring the full flight envelope in cruise, climb, at altitude and during descent, the X3 validated this high-speed concept’s qualities – including outstanding stability, intuitive piloting characteristics, as well as low vibration levels without the need for anti-vibration systems.
The X3 also served as an ambassador of innovation during a demo tour in the U.S. in the summer of 2012 to demonstrate this advanced high-speed transportation system’s unique operational capabilities for both civil and military operators. The final stop at Washington D.C., where the X3 landed on the helipad of the Pentagon, marked a symbolic moment in the X3's frontier-pushing history. Three months later, the X3 was in the spotlight at the ILA Berlin air show where it participated in flight demonstrations and gave European aficionados an up-close look at its unique characteristics.
Airbus Helicopters foresaw a wide range of potential applications for a hybrid helicopter configuration that may be developed from the X3 concept, offering an advanced, cost-effective vertical takeoff and landing (VTOL) transportation system with speeds of a turboprop-powered aircraft and the full-flight capabilities of a helicopter. Its applications could include long-distance search and rescue (SAR) operations, coast guard missions, border patrol flights, passenger transport and off-shore airlift, along with inter-city shuttle services.
The combination of higher cruise speeds and excellent VTOL performance also is well-suited for military missions, such as special forces operations, troop transport, combat SAR and medical evacuation. The X3 concept is particularly well suited for missions requiring long transit flights at high speeds, while retaining full vertical lift and hover capabilities – all at a very affordable cost.
The X3 resulted from a rapid-paced program that utilized one of Airbus Helicopters’ Dauphin helicopters as the airframe, providing a test platform with a maximum take-off weight of 5,200 kg. In addition to the more symbolic aspect of achieving record velocities for a rotorcraft, the X3’s flight evaluations enabled Airbus Helicopters to further explore the behavior of main rotors at high speeds, while also assessing the effectiveness in drag optimization.
In June 2014 Airbus Helicopters’ high-speed demonstrator, the X3, entered its new home in the Innovation and High Speed hangar of the Musee de l’Air et de l’Espace – France’s national air and space museum – at Paris-Le Bourget airport. The ceremony was attended by France’s minister of defense, Jean-Yves Le Drian, and the president of the French aerospace industries association GIFAS, Marwan Lahoud. The X3 is strategically exhibited alongside other high-speed legends such as Europe’s supersonic Concorde jetliners, which once transported commercial passengers at twice the speed of sound.
Russia is reportedly allocating large sums to build an advanced high-speed helicopter. A prototype engine is expected to be unveiled by the Klimov design bureau later this year. Rival aircraft manufacturers – Eurocopter and Sikorsky – are testing prototype models, with the Sikorsky X2 surpassing 460 kmph and Eurocopter X3 featuring slightly lower speed but superior cost-effectiveness.
The design of a large-scale compound rotorcraft demonstrator dubbed LifeRCraft (Low Impact Fast & Efficient RotorCraft) will be led by Airbus Helicopters in the framework of Europe’s Clean Sky 2 Joint Technology Initiative, which was formally launched in July 2014 at Brussels. The go-ahead for this second phase of the Clean Sky effort will enable Airbus Helicopters to apply expertise gained from its highly successful X3 hybrid testbed, while also benefitting from the company’s track record of helicopter innovation in airframe construction, integrated systems, flight controls and aerodynamics. The LifeRCraft architecture combines fixed wings for energy-efficient lift, open propellers for high-efficiency propulsion, and a main rotor that provides VTOL (vertical takeoff and landing) flight capabilities.
Launched in 2008, Clean Sky is a multi-year public-private partnership involving the European Commission and Europe’s aviation industry, with the goal of bringing significant step changes to reducing the sector’s environmental impact. Through a multi-phase approach, Clean Sky 2 is the continuation to the progress achieved in the first Clean Sky Programme which will end in 2017. It intends to speed up technological breakthrough developments and shorten the time-to-market for more competitive and cleaner air transport solutions tested on full scale demonstrators. Through open calls Clean Sky 2 will involve a range of partners throughout Europe, in particular SMEs.
Such a future compound aircraft would combine higher cruise speeds with excellent vertical takeoff and landing performance at affordable operating costs, making it well-suited for such vital public service duties as emergency medical airlift, search and rescue, coast guard and border patrol operations; while also contributing to the overall enhancement of mobility through operations ranging from passenger transport and inter-city shuttle services to off-shore airlift for the oil and gas sector.
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