The Behm Acoustic Sounder for Airplanes with Reference to Its Accuracy (1930)
NASA Technical Reports Server (NTRS) · leaf 21
N.A.C.A. Technical Memorandum No.583 Fig. 5 … Direction of flight o a o (By calibration of Impulse Echo instruments) microphones a>hsoll= 5 m 4^soll=40 m b, " =10 m e, » =60 m =20 m =80 rn =100 m oil Fig.5 Enlargement of Fig.4 for microphone distances up to 10 m.
NASA Technical Reports Server (NTRS)
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