U.S Eurocopter flight demo aimed at proving hybrid helicopter is 'not a small toy'
The distinctive sight and sound of 's X3 hybrid helicopter turned heads at last year's Paris air show, and now the manufacturer plans to make an impact on prospective civil and military users with the demonstrator in the U.S.
Eurocopter's planned midyear X3 exhibition comes amid a flurry of activity among competing unconventional rotorcraft developments asadvances its S-97 Raider high-speed semi-compound design and accelerates certification plans for the re-branded AW609 tiltrotor.
All are aimed at bringing higher speed and more efficient operations to the rotorcraft market, which Eurocopter believes still needs plenty of convincing about the merits of these unusual configurations. “It's not a small toy, it's a real helicopter,” says President and CEO Lutz Bertling.
The demonstration is being organized mainly because “the major operators are here in the U.S. in the emergency medical and offshore oil and gas markets, and we need to convince them that it's a high-productivity concept. We need to convince them of its simplicity,” he adds. “Of course we'd also like to show the U.S. Army that they should take it into account for the JMR,” Bertling says, referring to the Joint Multi-Role technology demonstration program.
Although no further awards are anticipated for the JMR, which is aimed at a medium-utility replacement for theBlack Hawk in the 2025-30 period, Bertling believes the demonstrator may spark potential interest for this and other roles. The JMR is already a tightly contested program with AVX Aircraft, Bell , Boeing and Sikorsky conducting trade studies aimed at producing two competing rotorcraft demonstrators in 2017.
Based on a modified EC155, the X3 is configured with a five-blade main rotor and two tractor propellers on short-span fixed wings. Power is provided by twin/ RTM322 turboshaft engines driving the main rotor and propellers through a modified transmission system. “Normally there's one outlet of the main gearbox and one tail rotor, and the increase in complexity (with the X3) is that there is one more outlet for the gearbox and one more propeller,” says Bertling.
Flight tests of the aircraft, which reached a top speed of 232 kt. in May 2011, are about to resume following a detailed inspection period. Although Eurocopter would like to see the X3 flown to higher speeds than the 250 kt. achieved by Sikorsky's semi-compound design, “to be honest, speed is not the most important thing,” says Bertling. The key objective is to “gain experience with the concept.”
With a wing designed to offload the rotor and provide up to 80% of the total lift, the hybrid concept is aimed at flying both faster and 50% higher than current helicopters. According to Bertling, this brings it into the operating realm of the tiltrotor without the additional cost, with a target price around 20% higher than comparable helicopters. As well as versions for long-distance search-and-rescue, coast guard and other missions, Bertling envisions a potential 19-seat commuter. “I strongly believe you could go to 40 to 50 passengers, but then we're talking about the 2030s,” he says, adding that all production versions “will be significantly different from the demonstrator.”
In parallel with the X3, Eurocopter is also developing the conventionally configured, next-generation X4 aimed at the AS365 Dauphin/EC155 replacement market in the medium-twin category. An initial version will enter service in 2017, powered by a Pratt & Whitney Canada (PWC) engine, with a more advanced variant following in 2020 offered with the choice of Turbomeca's upcoming TM800.
“As with the EC135, we will offer two engines,” says Bertling. “We prefer not to combine helicopter development and engine development. If you try to combine two things it's a moving target. So the first version of X4 initially will fly with a PWC engine, though clearly Turbomeca will be on board.”