Air on a G String...

[ORAC]

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.

[BEagle]

Isn't that why the Islander was such a good STOL aircraft? The intense vibration throughout the structure causing the increase in lift coefficient of which you speak?

There was a good spoof once posted about why this droning old device was so successful.

[Grunf]

As long as someone on production side decides to do a detailed vibration analysis it would be good idea.

Somehow most of the engineering world inside big (and little as well) manufacturers is concentrated on static loads meaning they approach a/c structure as not exposed to vibrations. Rarely you will see something done on that side.

As long as there are no problems it is OK.

Islander is or better was an exception since someone actually bothered to look into that.

Cheers

[Fatty]

The noise and vibration was designed in to the Islander/Defender on purpose.

They realised that Concorde performed well, and was noisy. Therefore in order for the BN2 series to perform well it needed to be noisier.

If you think I am wrong think about the Trilander. That third engine is only there for the extra noise.