Air on a G String...
New Scientist - 27th Aug:
Singing wings could reduce the number of fatal crashes of small aircraft. The idea is to prevent the plane stalling by applying a piezoelectric film to the wings to help maintain a smooth airflow.
Stalls account for around one-quarter of fatalities involving small planes, and are caused by a loss of lift when an aircraft turns too tightly or too flies too slowly. "The air can no longer remain attached to the wing and it tends to break off in large sheets", says ian Salmon, an engineer with Qantas Airways in Sydney, Australia, who conducted the research while at the University of New South Wales.
Applying an electric current to the film causes it to vibrate, which produces the sound and makes it less likely that the airflow will break away. Tests using a sinusoidal tone of about 400 hertz (close to the G above middle C) showed an increase in lift of 22 per cent.