VP,
Do you remember which issue? Search seems to be limited:
issue 82 - Eurocopter, an EADS company
MrDrumpy,
Interesting article but i'm not sure the presenter fully understood the benefits of active vibration flaps. Spreading out the tip vortices (like the owl) will help to reduce speeds near the tip of a fixed wing, but the sound from this is already minimal, but the only way i can see it impacting a helicopter is blade-vortex interaction. The main benefit of active servo flaps is to reduce blade vibration, hence structural loads into the fuselage. But having better controlled blade tips may inturn reduce the peak vorticity strength to nearer the mean vorticity strength around the azimuth. More controlled tip vortices and reduced fuselage vibration may both explain the significant 6dB(A-weighted) which was mentioned.
Dave,
How did that servo flap system work? It looks to me as if designed to damp out vibration by having it's CG ahead of the blade, so that the return to TPP restoring force is reduced by the servo Rel_AOA. At about 2/3rds radius i imagine it worked best at 3P blade vibration, but probably also handled 1P and 5P vibrations.