Story ID: 
Details emerge on X4 Dauphin replacement
By: Thierry Dubois
Caption: Eurocopter has fully launched the replacement program for its AS365/EC155 Dauphin and is targeting 2016 for entry into service for the first iteration, wit
Word Count: 617
Eurocopter has fully launched the replacement program for its AS365/EC155 Dauphin and is targeting 2016 for entry into service for the first iteration, with a more advanced version to enter service several years later. Codenamed X4, the helicopter will feature a radically new cockpit, fly-by-wire controls and low-noise main rotor blades. It will compete with the AgustaWestland AW169 and the Sikorsky S-76D in the 9,000- to 12,000-pound category.
At the Paris Air Show, Eurocopter CEO Lutz Bertling told journalists that the first version, planned for 2016, will make use of technologies that have already been ground-tested. The second iteration, in 2020, will use technologies that are at the feasibility-study stage today. AIN understands this approach will enable Eurocopter to get the helicopter to market at a time when competitors are still reviewing their options, and pitch major technology advancements shortly thereafter.
Other than confirming that the French government is funding the X4 program through €250 million ($350 million) in refundable loans that will be distributed to Eurocopter and its partners, Safran and Thales, Bertling said no more about the new helicopter. Later that same week, however, Safran (of which engine maker Turbomeca and avionics specialist Sagem are a part) unveiled many more details. Sagem will design a fly-by-wire (FBW) flight control system with sidesticks. It was not made clear whether these FBW controls will appear in 2016 or 2020. The X4 will probably be the first civil helicopter in service with such controls, excepting the slow-selling Kazan Ansat light twin from Russian Helicopters, the first FBW helicopter with a commercial application.
As early as 2007, Eurocopter research engineers told AIN that they were considering FBW controls, including electric actuators, for entry into service on civil helicopters between 2012 and 2017. The expected benefits, for the pilot, were improved handling qualities and more precise flying. Passengers could benefit from the smoother ride of FBW. On the maintenance side, FBW controls were supposed to reduce the frequency for scheduled checks, compared with hydraulics.
The cockpit will look quite different from those of today. Apparently, the main display will be projected on the windshield itself, with the flight path shown in highway-in-the-sky style. In a more conventional head-down position, a central display will present navigation and power information. On the pedestal, between the two seats, what is likely to be a touchscreen displays the rest of the information. Again, it is still unclear whether this will be for the first or second X4 variant.
Turbomeca is working on the 1,100-shp-class TM800 engine to replace the current Arriel 2 and TM333 turboshafts. Testing of compressor and combustor demonstrators will begin this year. The compressor will have a twin-centrifugal design with variable-pitch blades and an increased pressure ratio. Turbomeca will also use “the latest generation of single-crystal materials” and three-dimensional aerodynamic design for all the blades and vanes.
Engine certification is planned for 2016. Turbomeca targets a 20-percent cut in specific fuel consumption at cruise. The expected percentage reduction is the same for maintenance costs.
The main rotor blades appear to be an application of Eurocopter’s Blue Edge concept. A double-swept shape reduces the noise generated by blade-vortex interactions. BVI occur when blade-tip vortices interact with the rotor blades. A five-blade Blue Edge main rotor logged 75 hours on an EC155 testbed, demonstrating a noise reduction of three to four decibels, Eurocopter said last year.
A source close to Eurocopter pointed out to AIN that the artist renderings the company released are quite preliminary and the design is still subject to change.
The company has sold some 900 Dauphins in 30 years. There is still an improved version in development, the AS365 N3e.