§ Sir A. Herbertasked the Minister of Supply (1) what his Department is doing or intends to do to reduce the noise of civil aeroplanes and whether the main difficulty is mechanical or financial;
(2) what researches or experiments are being made by his Department with a view to the reduction of the noise of aeroplanes and what progress has been made.
§ Mr. G. R. StraussResearch directed towards the moderation of noise is being undertaken by the Ministry of Supply in conjunction with leading aero-engine firms. A Noise Suppression Panel meets regularly at the Royal Aircraft Establishment and my Department has the assistance of the Acoustics Section of the National Physical Laboratory. Noise within aircraft can be reduced by sound insulation, but there is little hope of reducing appreciably the noise from aircraft in flight. The difficulty is mechanical; aircraft propulsion depends upon the transfer of energy to a stream of air and the creation of noise is unavoidable.