High Fidelity Multidisciplinary Tool Development For Helicopter Quieting (original) (raw)
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Canadian Acoustics, 2015
Rotary aircraft maintenance personnel, similar to helicopter aircrew, are exposed to high noise levels while working in and around aircraft. The noise environment may include tonal rotor noise, high frequency engine, transmission and hydraulic systems noise as well as broadband noise. Prolonged exposure may lead to hearing loss if the designated hearing protection is inadequate or improperly fitted. A thorough interior and exterior noise exposure measurement campaign was conducted on the Royal Canadian Air Force’s CH-147F helicopter. A number of representative operational states for maintenance and tarmac conditions were investigated and referenced to the Canadian Aviation Occupational Health and Safety Regulations. The results were analyzed to determine the acoustic performance of ground maintenance crew hearing protection equipment.
Canadian Acoustics, 2017
Royal Canadian Air Force (RCAF) CH-149 Search and Rescue helicopter aircrew operate in dynamic operational conditions including long-duration search and rescue as well as strenuous open-door hoisting activities. During emergencies, civilians and ground crew may be exposed to aircraft noise within the cabin as well as in the external proximity of the aircraft. Due to the demanding nature of search and rescue activities, civilians, aircrew and ground crew may or may not be equipped with properly fitted hearing protection throughout a noise exposure event. The objective of the recent National Research Council (NRC) – Department of National Defence joint investigation was to characterize the noise levels of the CH-149 helicopter cabin and cockpit throughout 48 representative flight and ground conditions. This paper will outline the NRC ground external noise measurement of the CH-149 Cormorant at Comox Canadian Forces Base, January 2017. The contextual performance of the current in-servi...
The Journal of the Acoustical Society of America, 1997
The rotorcraft noise model (RNM) is a multiplatform computer program being developed for NASA-Langley Research Center which calculates sound levels at receiver positions on the ground from helicopter and tiltrotor operations. RNM calculates levels at positions on a uniform grid or a specific defined locations. The basic computational model written in FORTRAN calculates maximum A-weighted sound level, sound exposure level (overall, C- and A-weighted), and effective perceived noise level (EPNL). Contained within the program are sound propagation and EPNL algorithms that are the same as, or equivalent to, corresponding algorithms in NASA’s Aircraft Noise Prediction Program (ANOPP). Acoustic properties of the noise source are defined by a set of sound-pressure noise spheres. One set of noise spheres provides broadband data in the form of one-third octave band sound-pressure levels. The other set of noise spheres provides narrow-band data in the form of pure-tone sound-pressure levels an...
2012
The link between the heliports, environmental quality and safety is an important challenge in the field of helicopter transport. This challenge is especially crucial when the helicopter operations are carried out on densely urbanized areas. Often these areas have significant constraints and obstacles, particularly in terms of noise pollution. These constraints make the approach/takeoff maneuvers very complicated. The theme of the environmental sustainability of the rotorcraft is strongly felt in many countries. The production of noise is subjected to numerous rules and procedures, which tend to improve the acceptability of the helicopter by residents in neighboring areas to verti/heliports. The attention of manufacturers towards the problems of noise compatibility has produced technological innovations to reduce emissions, such as the shape of the tip of rotor blades, a speed reduction of rotation of the rotors, etc. Environmental concerns are becoming increasingly important when si...