Noise considerations for tiltrotor

Huston, R. J.; Golub, Robert A.; Yu, J. C.

doi:10.2514/6.1989-2359

Cited by 6 publications

(2 citation statements)

References 2 publications

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“…Greater than 10 SELdB noise reduction was measured on centerline 00-08-20 for a small area between 6,300 and 8,800 ft (1,920…”

Section: Discussionmentioning

confidence: 97%

“…Commuter aircraft, flying fairly short routes with relatively few passengers, make up a significant portion of the total airport operations at a large number of these airports, thus significantly limiting the total number of passengers that can use those airports each day (Ref. 1). Tiltrotor aircraft, with their unique capability to take off and land vertically while still flying like an airplane during cruise, provide a potential alternate means of transportation that could link major cities, thus alleviating some of the demand on airports.…”

Section: Introductionmentioning

confidence: 99%

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NASA/Army/Bell XV-15 Tiltrotor Low Noise Terminal Area Operations Flight Research Program

Conner¹,

Edwards²,

Decker³

et al. 2002

J. Am. Helicopter Society

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To evaluate the noise reduction potential for tiltrotor aircraft, a series of three XV-15 acoustic flight tests were conducted over a five-year period by a NASA/Army/Bell Helicopter team. Lower hemispherical noise characteristics for a wide range of steady-state terminal area type operating conditions were measured during the Phase 1 test and indicated that the takeoff and level flight conditions were not significant contributors to the total noise of tiltrotor operations. Phase 1 results were also used to design low-noise approach profiles that were tested later during the Phase 2 and Phase 3 tests.These latter phases used large area microphone arrays to directly measure ground noise footprints. Approach profiles emphasized noise reduction while maintaining handling qualities sufficient for tiltrotor commercial passenger ride comfort and flight safety under Instrument Flight Rules (IFR) conditions. This paper will discuss the weather, aircraft, tracking, guidance, and acoustic instrumentation systems, as well as the approach profile design philosophy, and the overall test program philosophy. Acoustic results are presented to document the variation in tiltrotor noise due to changes in operating condition, indicating the potential for significant noise reduction using the unique tiltrotor capability of nacelle tilt. Recommendations are made for a final Presented at the Tiltrotor/Runway Independent Aircraft

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“…Greater than 10 SELdB noise reduction was measured on centerline 00-08-20 for a small area between 6,300 and 8,800 ft (1,920…”

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

NASA/Army/Bell XV-15 Tiltrotor Low Noise Terminal Area Operations Flight Research Program

Conner¹,

Edwards²,

Decker³

et al. 2002

J. Am. Helicopter Society

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Numerical calculation and analysis of aero-acoustic characteristics of tilt rotor in different tilt angles

YUAN,

SUN,

et al. 2024

西北工业大学学报

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The numerical calculation model for the aero-acoustic analysis of a tilt rotor was established by combining the free wake method and the FW-H (Ffowcs Williams-Hawkings) equation. The numerical method was validated by using the tilt rotor′s aero-acoustic test results. The aero-acoustic characteristics of dual tilt rotors that take into account the force and moment trim of an aircraft in its typical transition path were calculated. The unsteady air load of a rotor blade and its noise data in different observational positions were acquired. The acoustic directivity and sound pressure level of the tilt rotor in its different tilt angles were analysed. The results show that: the acoustic directivity characteristics of an isolate tilt rotor and dual tilt rotors were quite different due to the superposition and offset during noise radiation; the sound pressure level first increases and then decreases along with the rotor′s tilt angle; the maximum sound pressure level occurs at the tilt angle of 30 degree; the acoustic directivity and sound pressure level in different tilt angles vary due to multiple factors such as the Mach number at the rotor tip, air load and rotor orientation.

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Flowfield and Acoustic Measurements from a Model Tiltrotor in Hover

Polak¹,

George

1998

Journal of Aircraft

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Noise considerations for tiltrotor

Abstract: The development and validation of tiltrotor technology by the U.S. Government and industry in the past two decades has placed the U.S. in an international leadership position in tiltrotor aircraft. The current military V-22

Cited by 6 publications

References 2 publications

NASA/Army/Bell XV-15 Tiltrotor Low Noise Terminal Area Operations Flight Research Program

NASA/Army/Bell XV-15 Tiltrotor Low Noise Terminal Area Operations Flight Research Program

Numerical calculation and analysis of aero-acoustic characteristics of tilt rotor in different tilt angles

Flowfield and Acoustic Measurements from a Model Tiltrotor in Hover

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