NOISE IN AIRCRAFT.

Waikato Times, Volume 120, Issue 19984, 7 September 1936, Page 10

NOISE IN AIRCRAFT.

SOME TECHNICAL POINTB. A recent report of Messrs E. Z. Stowell and A. F. Deming, of ths National Advisory Committee fop Aeronautics, Langley Field, indicate* that something more radical than better sound installation of aircraft cabins must be found by scientists It travellers by air are to be spared the roar of airscrew’s.

I In a recent study of the noise of two-bladed airscrews It was found that the greatest noise source is the I roar of the fundamental frequency. The basic noise is a musical note | having twice the frequency with j which the airscrew is rotating. In the j airscrew roar as many as 50 to GO harmonics of this fundamental note 1 appear. In discussing the Importance of airscrew noise tests the scientists state: “It is evident that although i passengers in a commercial aircraft i may find the noise temporarily disagreeable the effect of the noise upon the pilots who hear it day after day will be greater, and may even interfere seriously with their efficiency.*' The two-bladed airscrew’, they point out, radiates more noise than does almost any other continuously operating device known to man. The only exceptions are certain special signalling devices.