Accession Number:

ADA301581

Title:

Noise Environs and Helmet Performance for the P-1127 V/STOL Aircraft.

Descriptive Note:

Final rept. Oct 67-Mar 68,

Corporate Author:

AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH

Report Date:

1968-12-01

Pagination or Media Count:

29.0

Abstract:

The purpose of this evaluation was 1 to measure the acoustic noise environment in the cockpit of the United Kingdom Hawker Siddeley P-1127 VSTOL aircraft that would serve as an acoustic guideline for cockpit noise levels of other VSTOL aircraft being contemplated or under construction, and 2 to determine the acoustic attenuation of various Air Force flight helmets in the inventory or being contemplated for Air Force inventory items. Cockpit sound pressure levels in the United Kingdom Hawker Siddeley P-1127 VSTOL aircraft at engine rpm settings of idle, 45, 60, 80 and maximum were measured. The cockpit noise environment at maximum engine rpm was reproduced in the laboratory and used to obtain objective attenuation data for three Air Force flight helmetliner configurations HGU-2AP helmet with 17P liner, H-154 ear cup liner and Gentex ear cup liner. Measurement of Real-Ear Attenuation at Threshold REAT were also accomplished on the helmetliner configurations. On the basis of the cockpit noise environment and the attenuation characteristics of the helmetliner configurations tested, no hearing damage would be expected to result when exposure durations do not exceed 1 hour continuous exposure. The Gentex ear cup liner provides approximately 4 to 9 dB more attenuation than the 17P liner throughout the frequency range tested and from 13 to 26 dB more attenuation than the H-154 ear cup liner at test frequencies from 3 to 8K Hz.

Subject Categories:

  • Acoustic Detection and Detectors
  • Infrared Detection and Detectors

Distribution Statement:

APPROVED FOR PUBLIC RELEASE