Britten-Norman and Hartzell Propeller have recently developed experimental three-bladed propellers and installed them on a BN2B Islander. First indications show a noise reduction of between five and seven dB(A), says Britten Norman.\r "The propellers, which have a marked swept "scimitar" profile, are specifically designed to reduce noise and enhance efficiency. Improved aerofoil efficiency results in the same power transfer at reduced rpm with the consequential lower tip speed, reducing noise," said Britten Norman. \rThe trials form part of an ongoing programme supported by the UK Department of Trade and Industry to reduce the noise impact of piston-powered light aircraft in general aviation. \rThe next phase of the programme will concentrate on exhaust noise reduction, with Britten-Norman working alongside silencer specialists from Europe and the US. Work is due to be finished by mid-2000, with noise reduction equipment becoming the production standard on all Islanders, and retrofits available to existing operators.