20 octobre 2021 Pierre Perrin-Monlouis
Decisive step towards lowering noise emissions and vibrations through adaptive rotor controls
Marignane, 08 September 2005
On 8 September 2005 at 2 p.m., the experimental helicopter of the type BK 117 lifted off from the Eurocopter site at Donauwörth for its official maiden flight with an electrical flap control system. This means that Eurocopter has now reached a milestone in the development of a trendsetting helicopter control technology and thus positioned itself ahead of the international technology competition concerning the area of so-called “adaptative rotor systems,” surpassing the key competitors Japan and the U.S.
Significantly Lower Noise and Vibration LevelsThe primary objective of this new type of control method is to reduce the system-inherent, relatively high noise level of the rotor blade tip vortices to levels significantly below those of modern Eurocopter helicopters with limit values already below the required standards.
At the same time, the vibrations that components and passengers alike are subjected to shall be reduced significantly in order to increase the comfort of passengers during the flight and expand the capacity of future helicopters and thereby promote commercial utilization of these aircraft.
The development program concerning adaptative rotor systems is sponsored by the German Ministry of Economics and Labor and is based on cooperation between the partners Eurocopter Deutschland (management, design, production, controls, tests), the EADS Corporate Research Centre CRC (piezoceramic actuators), DaimlerChrysler (energy supply, data transfer), as well as the German Aerospace Center DLR (controls, data transfer).
Flaps at the Blade Trailing Edge – Piezoceramic ActuatorsThe control system uses three flap modules located at the trailing edge of each rotor blade. The piezoceramic actuators integrated into the blades respond with a length change to varying electrical voltages and thereby move the rotor flaps 15 to 40 times per second.
Actuation is carried out by means of an optical waveguide via a controller without requiring pilot interaction. It neutralizes the blade slap noise typically associated with helicopters that are descending and lowers the overall noise level by up to 6 dBA (a decrease around 10 dBA corresponds roughly with a 50% lower noise impression).
The asymmetrical impinging flow of a rotor generates vibration that can be reduced by as much as 90% by generating counter-vibration, which in turn increases the service life of important components as well as passenger comfort.
Eurocopter COO Friedrich Dörhöfer and the Ottobrunn Eurocopter project team around Michael Stephan were completely satisfied with the results of this first flight:
“The now tested demo system has yet to be miniaturized and optimized for commercial utilization. And as technology leader for bearingless rotor systems, we are currently integrating another, further improved flap type into a bearingless rotor of the latest generation,” explained Dr. Valentin Klöppel, Aeromechanic and Flight Control Program Manager at Eurocopter. “The technology will be generally applicable to all larger helicopters once all tests have been successfully concluded. This is likely to be in 2012 or beyond.”
Eurocopter is a wholly-owned subsidiary of EADS. EADS is a global leader in aerospace, defence and related services. In 2004, EADS generated revenues of € 31.8 billion and employed a workforce of about 110,000. The EADS Group includes the aircraft manufacturer Airbus, the world’s largest helicopter supplier Eurocopter and the joint venture MBDA, the international leader in missile systems. EADS is the major partner in the Eurofighter consortium, is the prime contractor for the Ariane launcher, develops the A400M military transport aircraft and is the largest industrial partner for the European satellite navigation system Galileo.
For further information, please contact:
Jean-Louis ESPES Eurocopter
Tel.: + 33 (0) 4 42 85 95 55
Fax.: + 33 (0) 4 42 85 95 64
mailto: [email protected]
Christina GOTZHEIN Eurocopter Deutschland GmbH
Tel.: + 49 (0) 89 60 00 64 88
Fax.: + 49 (0) 89 60 00 44 37
mailto: [email protected]
Jesus RUIZ Eurocopter España, S.A.
Tel.: + 34 91 511 04 70
Fax.: + 34 91 511 04 69
mailto: [email protected]
www.eurocopter.com
