Accession Number : AD0618715

Title :   ACOUSTICAL EVALUATION OF X-20A DYNA-SOAR FULL-PRESSURE SUIT ASSEMBLIES.

Descriptive Note : Final rept.,

Corporate Author : AEROSPACE MEDICAL RESEARCH LABS WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Sommer,Henry C. ; Hille,Harald K.

Report Date : MAY 1965

Pagination or Media Count : 30

Abstract : Data on the subjective Real-Ear Attenuation at Threshold (REAT) and noise transmission measurements at the helmet microphone and ear cup were obtained for two models of the suit assembly. The first models tested and evaluated were called the 'training' models and were custom fitted for each of the Dyna-Soar pilots. During the test program, in which the pilots were acting as experimental subjects, the X-20A program was cancelled and only four of the six pilots completed the tests. The results of this evaluation revealed that various features of the assembly were unsatisfactory; therefore, an improved version was fabricated to correct the undesirable deficiencies. From the acoustical standpoint, the assembly was redesigned to eliminate a resonance at 250 cps with the visor open. This improved second model was called the 'flight ready' model. The report describes a comparative acoustical evaluation of the training models and flight-ready models of the suit assemblies. Evaluation consisted of (1) the subjective measurement of RealEar Attenuation at Threshold (REAT) and (2) the measurement of transmission loss through the helmet at the helmet microphone and ear cup position.

Descriptors :   (*PRESSURE SUITS, ACOUSTIC PROPERTIES), (*ASTRONAUTS, AUDITORY PERCEPTION), HELMETS, NOISE, SOUND TRANSMISSION, ATTENUATION, TRAINING, FLIGHT CLOTHING, EXPOSURE SUITS, AUDITORY SIGNALS, SPACECRAFT CABINS, EARPHONES, MICROPHONES, COMMUNICATION EQUIPMENT, BOOST GLIDE VEHICLES

Distribution Statement : APPROVED FOR PUBLIC RELEASE