Date: 12 Nov 2003
Time: 11:01
ONERA and DLR have launched a four-year programme on dynamic stall, which includes experimental and theoretical studies of this dangerous phenomenon. In another important safety-related area, crashworthiness research is currently focused on composite structures, where there is a need to improve prediction codes and validate them through testing.
Researchers are also looking at external noise, a problem which restricts civil helicopter operations in urban areas. A major project is underway with Eurocopter to finalise and flight-test a quiet main rotor, while if possible further improving the performance of the ONERA/DLR-designed Erato rotor.
“Wind-tunnel tests have demonstrated the ability of the Erato rotor to reduce noise by 4 to 7 dBA in descent flight configuration,” ONERA told www.air-rescuetek.com.
Researchers are investigating ways of predicting and reducing vibrations to improve passenger comfort by developing enhanced tools for finite-element modelling of a helicopter and its components. This approach also involves coupling of structural and aerodynamic codes to give a more precise estimate of the unsteady loads induced by the rotor, which are the primary source of vibrations. Long-term studies are also under way into the concept of active-twist rotor blades.