Flight tests of Hartzell three-bladed propellers on a Britten-Norman BN2B piston-engined Islander have exceeded original projections, revealing a noise reduction of up to 7dB(A), according to the UK general aviation aircraft manufacturer.
"The experimental props, through the lower tip speed and scimitar shape, reveal significant performance and efficiency benefits to the aircraft," says Britten-Norman, which expects demand for its piston-powered Islander to increase after certification of the new propeller, due later this year.
Trials of the all-metal three-bladed experimental propellers, built by Hartzell as part of NASA-sponsored research, are being performed at Britten-Norman's Bembridge, Isle of Wight facility, forming part of a UK Government-backed programme to address the growing environmental concerns over noise from general aviation aircraft in Europe.
Britten-Norman says: "As well as its use as a short-haul passenger transport aircraft, the Islander is well established as an aerial surveillance platform with law enforcement agencies around the world." It adds: "Operations typically require flying low-level orbits over urban areas often at night. It is our goal to minimise noise emission to the local populace in these areas."
Britten-Norman plans to kick start the final phase of the nine-month programme in March, testing US and European designed silencers, which it anticipates will reduce further the noise level.
Source: Flight International
