A piezoelectric-powered flapping wing that uses mechanical linkages could be windtunnel tested early next year as part of a £435,000 ($745,000) project at the UK’s Cranfield University. The work will conclude in 2008.

Although piezoelectric material has the advantages of energy efficiency, fast response times, and large forces generated when a current is passed through it, its main disadvantage is a small dimensional change with the applied voltage. A larger change is needed to create the muscle-like effect to move the wing significantly. The mechanical links are used to amplify the movement obtained from the piezoelectric material.

To overcome this limitation, US researchers have used four-bar links to amplify the extension effect, but the UK researchers have a different link design.

“Ours is a totally different approach, but we are trying to work out if our approach is as good,” says Cranfield University professor of engineering nano-technology Roger Whatmore.

By next year, his team hopes to have a one-degree-of-freedom flapping wing ready for testing. The plan is to follow that with a flapping and sweeping wing, and then finally with a flapping, sweeping and pitching wing.

Another flapping project at Cranfield uses a wholly mechanical system (Flight International, 28 June–4 July).

Source: Flight International