Subjective Response to Synthesized Flight Noise Signatures of Several Types of V/STOL AircraftNational Aeronautics and Space Administration, 1968 - Short take-off and landing aircraft - 92 pages |
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Page 27
... noise reduction requirements shown in Table I. Terminal noise . Inlet noise . - During terminal operation , the fan lift type of VTOL aircraft requires a 25 to 35 decibel reduction in cruise engine intake noise , depending on whether ...
... noise reduction requirements shown in Table I. Terminal noise . Inlet noise . - During terminal operation , the fan lift type of VTOL aircraft requires a 25 to 35 decibel reduction in cruise engine intake noise , depending on whether ...
Page 30
... inlet noise problem . Inlet noises from the other configurations need serious attention only if cruise operation at a 500 - foot altitude is required . The require- ments are , however , not so restrictive that whatever feasible ...
... inlet noise problem . Inlet noises from the other configurations need serious attention only if cruise operation at a 500 - foot altitude is required . The require- ments are , however , not so restrictive that whatever feasible ...
Page 53
... noise of the wing - mounted lifting fans was pre- dicted according to a method developed in reference 8 . In cruise , there are considerably fewer noise ... inlet ( reference 5 ) , and broad band jet exhaust noise ( references 6 and 7 ) from ...
... noise of the wing - mounted lifting fans was pre- dicted according to a method developed in reference 8 . In cruise , there are considerably fewer noise ... inlet ( reference 5 ) , and broad band jet exhaust noise ( references 6 and 7 ) from ...
Contents
SUBJECTIVE TESTING | 16 |
Some Aircraft Operational Considerations | 23 |
Other Noise Rating Methods | 31 |
2 other sections not shown
Common terms and phrases
aircraft noise aircraft sounds amplitude amplitude-time history broad-band BY-PASS EXHAUST Comparative Peak Perceived COMPARATIVE PEAK PNdb Configuration cruise noise cruise operation CYCLES PER SECOND decibels Doppler shift electronically exhaust noise fan lift feet flight FREQUENCY IN CYCLES Helicopter Rotor inlet noise jet lift VTOL JET REFERENCE LEVEL IN BAND LIFT ENGINE Lift Fan LIFT JET LIFT TILT WING main rotor MEASURED PNdb LEVELS MICROBAR Noise Reduction Required noise signature peak perceived noise perceived noise level potentiometer predicted pure tone rating method RIGID ROTOR TANDEM rigid rotor VTOL rotational noise rotor noise ROTOR TANDEM ROTOR ROTOR TERMINAL simulated SOUND PRESSURE LEVEL spectrum shape SUBJECTIVE RESPONSE SUBJECTIVE TEST RESULTS SUBJECTS TAKING TEST synthesized tail rotor takeoff TANDEM ROTOR CRUISE Tandem Rotor VTOL terminal noise terminal operation Terminal Spectrum test subjects TEST WHO THINK THINK S WORSE tilt wing VTOL tip speed Turbofan STOL Turboshaft V/STOL aircraft vortex noise