Sonic boom startle effects : report of a field study.

Abstract : The study reports the results of a sonic boom field study conducted in Sweden during October 1972. Ten female subjects were tested indoors on each of six days. Two age groups were studied: 20-35 and 50-65 years. Fighter aircraft flying at various heights over the test site produced booms with outdoor overpressures ranging from 60-640 N/sq.m. The number of booms extended from 5 to 13 per day. Subjects performed indoors on an arm-hand steadiness task. The results indicated that outdoor overpressures ranging from 70-120 N/sq.m. (26-35 N/sq.m. indoors) produced reflexive arm-hand movements in about 10 per cent of the subjects. Booms of 300 N/sq.m. (67 N/sq.m. indoors) and greater produced responses in about 75 per cent of the subjects. Between these extremes of overpressure there was the suggestion of a critical overpressure range lying between 150-180 N/sq.m. (40-46 N/sq.m. indoors) in which an abrupt increase in startle response occurred. (Modified author abstract)