Improved Acoustics, Less Internal And External Noise

Eurocopter will open the door to its development labs at this year’s Heli-Expo, showcasing some of its flight proven innovation technologies.  “This year’s Heli-Expo will demonstrate how our new technologies are being made ready for integration in Eurocopter’s product line, allowing our helicopters to outperform ever stricter and wider-ranging environmental and safety requirements, but as well contributing to reducing operating and maintenance costs,” stated Lutz Bertling, President and CEO of Eurocopter. “These issues have top priority for us, and we are responding with innovations that include more eco-efficient engine concepts, revolutionary main rotor blade designs that reduce noise and vibration, along with software and cockpit technologies - combined with advanced training methods - to enhance safety.”

The aim of the bluecopter technology program is to develop and validate advanced technologies which offer environmental benefits for new Eurocopter aircraft. This includes improved acoustics for lower noise inside the helicopter and externally, along with a reduced C02 and NOx footprint of the helicopter over its life cycle.

Eurocopter is displaying a new compact, high efficiency, high compression two-stroke engine called the OPOC (Opposite Piston Opposite Cylinder). This is in line with Eurocopter’s project to fly with a light single-engine helicopter powered by a diesel engine. The objective is to reach a power-to-weight ratio capable of challenging the advantages of a classic turbine, with the OPOC engine being one of the top options currently under evaluation.

The company is additionally pursuing several methods of optimizing main rotors to reduce external noise and cabin vibrations with the goal of introducing them as soon as feasible on the company’s helicopters. One way is to change the shape of the blade, using a technology called Blue Edge. The other is to integrate “intelligent” piezoelectric actuators into the trailing edge of the blade with a technology designated Blue Pulse. The Blue Edge main rotor blade provides a passive reduction in noise levels, using a double-swept shape that is very different from present-day blades. The aim of this program is to reduce the noise generated by so-called blade-vortex interactions (BVI), which occur when a blade impacts a vortex, created at the tip of the blade of any helicopter.

A five-blade Blue Edge main rotor has been flying since July 2007 on an EC155 testbed, logging 75 flight hours and demonstrating noise reductions of 3 to 4 dB, as well as very good performance of the blade. With this safe and simple means of measureable noise reduction for helicopters now validated, Eurocopter is ready to move Blue Edge into production applications.

EC155 File Photo

The piezo-active Blue Pulse rotor control system has the primary objective of reducing noise levels generated by the interference of the rotor blade tip vortices from one rotor blade with the following blades. In addition, it will significantly reduce vibrations within the helicopter airframe, increasing passenger comfort and extending the service life of sensitive components, The control system uses three flap modules located at the trailing edge of each rotor blade. The blades’ piezoelectric actuators move the rotor flaps 15 to 40 times per second in order to completely neutralize the “slap noise” typically associated with helicopters during descent. The Blue Pulse technology has been flying since 2005, showing a noise reduction of up to 5 dB. Eurocopter’s evaluations with Blue Pulse are continuing on an EC145, while the development of a miniaturized system for production applications is advanced.

Eurocopter is also demonstrating a Pilot Assistance System (PILAS) which utilizes a synthetic vision system that displays all relevant information for terrain, obstacles, air traffic, weather and airspace use, and other training and safety devices.

FMI: www.eurocopter.com