n the slipstream sound wave through an analyzer specially built for the at 180°, possibly owing to the shielding by the motor. purpose (reference 4). This instrument has been much As the propeller in these tests was rotating 1,800 improved since the publication of its description. In times a… … Figure 3.—Sound-measuring equipment. present in the sound-pressure measurements from the method consists in the use of electrical filters that pass 0-100 cycle band. The maximum in the total sound isolated frequency bands. Only instrument readings result from the use of this method. The layout of □…
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