Airbus Helicopters unveiled its Bluecopter demonstrator on July 7 at the company’s facility in Donauwörth, Germany. The modified EC135 has been flying since April 2014 with a number of technologies targeting a smaller environmental footprint.
Perhaps the most unexpected feature is the planned capability of so-called “single-engine operations,” aimed at optimizing engine power and thought to be in the early stages of development. In some phases of flight that do not require full power, such as cruise, the idea is to adapt the power setting of one engine to the lowest possible level that is still compatible with safety, chief technology officer Jean-Brice Dumont told AIN. Meanwhile, the other engine is running at a higher rpm. The combination of the two power settings is more efficient than having two engines operating at a medium speed.
Such operations can take place in only part of the flight envelope: the maximum speed should be 10 knots below the best-range speed and altitude should not exceed 5,000 feet, also factoring in a 1,600-foot safety height. The system, which essentially involves software, is still in early testing and the pilots simply shut down one engine. Eventually, an “eco mode” will automatically determine the best way to spread the power requirement between the two Pratt & Whitney Canada PW206B2 turboshafts.
Other features include Blue Edge swept blades, a first on a rigid rotor, for increased efficiency and lower noise; a T-shaped empennage, where the horizontal stabilizer is outside the main rotor's downwash; an active rudder; and water-based paint. Dumont said the program is on target to validate a 40-percent cut in fuel burn.