YC-15 EBF (Externally-Blown Flap) STOL (Short Takeoff and Landing) Airplane Fuselage and Interior Noise Environment.

摘要

The purpose of this effort was to investigate the exterior fuselage and interior noise of the USAF/McDonnell-Douglas YC-15 Advanced Medium-Range Short-Takeoff- and Landing Transport airplane. This aircraft employs an under-the-wing, externally-blown-flap powered lift system designed to create augmented lift, which creates an intense acoustic environment. The blowing of the flap produces higher noise levels at lower frequencies than does the jet alone, increasing the acoustic environment of the fuselage and inside the cabin. A combination of exterior flush-mounted microphones, accelerometers, interior centerline and sidewall microphones were used during this investigation. Test conditions analyzed included takeoff, cruise, landing, taxi, and ground static over the full range of operating conditions. The effects of different flight parameters are displayed in the form of the octave, one-third octave, and narrowband plots and are compared to the changes on the acoustic environment. (Author)