New 'Blue' Tech From Eurocopter Reduces Noise

Eurocopter announced last month it was developing new technology to reduce the noise generated by helicopter rotor blades. The company has named the new developments "Blue Edge" and "Blue Pulse" technology, and has tested them on an EC155. The reshaped Blue Edge blade tip reduced noise by up to 4 decibels with its cranked leading edge shape. In addition, Blue Pulse technology is designed with small surfaces at the trailing edge of the blade that can fluctuate 15 to 40 times per second. The goal is to reduce the interaction between the vortex of a lead blade with the following blade. Part of the noise from rotor blades results from the trailing blade slapping into the turbulent air churned up by the blade in front of it. Blue Pulse is designed to minimize that interaction to lower noise signature. Eurocopter intends to combine its Blue technologies in a so called "Bluecopter" with less noise and lower emissions.

Video: Eurocopter