Proceedings ArticleDOI
Engine design studies for a silent aircraft
Cesare A. Hall,Daniel Crichton +1 more
TLDR
This paper proposes engine mechanical arrangements that can meet the cycle requirements and, when installed in an appropriate airframe, will be quiet relative to current turbofans.Abstract:
The Silent Aircraft Initiative is a research project funded by the Cambridge-MIT Institute aimed at reducing aircraft noise to the point where it is imperceptible in the urban environments around airports. The propulsion system being developed for this project has a thermodynamic cycle based on an ultrahigh bypass ratio turbofan combined with a variable area exhaust nozzle and an embedded installation. This cycle has been matched to the flight mission and thrust requirements of an all-lifting body airframe, and through precise scheduling of the variable exhaust nozzle, the engine operating conditions have been optimized for maximum thrust at top-of-climb, minimum fuel consumption during cruise, and minimum jet noise at low altitude. This paper proposes engine mechanical arrangements that can meet the cycle requirements and, when installed in an appropriate airframe, will be quiet relative to current turbofans. To reduce the engine weight, a system with a gearbox, or some other form of shaft speed reduction device, is proposed. This is combined with a low-speed fan and a turbine with high gap-chord spacing to further reduce turbomachinery source noise. An engine configuration with three fans driven by a single core is also presented, and this is expected to have further weight, fuel burn, and noise benefits.read more
Citations
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Proceedings ArticleDOI
Airframe Design for "Silent Aircraft"
TL;DR: In this paper, the authors present a conceptual design of an aircraft with a calculated noise level of 62 dB at the airport perimeter, which is near the background noise in a well populated area, making the aircraft imperceptible to the human ear on takeoff and landing.
Journal ArticleDOI
Hybrid Wing Body Aircraft System Noise Assessment with Propulsion Airframe Aeroacoustic Experiments
TL;DR: The best configuration for reduction of jet noise used state-of-the-art technology chevrons with a pylon above the engine in the crown position, which resulted in jet source noise reduction, favorable azimuthal directivity, and noise source relocation upstream.
Patent
Oil baffle for gas turbine fan drive gear system
TL;DR: In this article, the epicyclic gear train employs a one-piece carrier in which the spaced side walls are interconnected with circumferentially spaced apart mounts to form a unitary structure.
Journal ArticleDOI
Ultrashort Nacelles for Low Fan Pressure Ratio Propulsors
TL;DR: In this article, an integrated fan-nacelle design framework is presented for low-FPR propulsors where fan and nacelle are more closely coupled than in current turbofan engines, combining a spline-based inlet design tool with a fast and reliable body-force-based approach for the fan rotor and stator blade rows.
Journal ArticleDOI
Airframe Design for Silent Fuel-Efficient Aircraft
TL;DR: In this article, the authors present a conceptual design of an aircraft with a calculated noise level of 62 dBA at the airport perimeter, making the aircraft imperceptible to the human ear on takeoff and landing.
References
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Journal ArticleDOI
Design of the Blended Wing Body Subsonic Transport
TL;DR: The Boeing Blended-Wing Body (BWB) airplane concept represents a potential breakthrough in subsonic transport efficiency as discussed by the authors, and work began on this concept via a study to demonstrate feasibility and begin development of this new class of airplane.
Proceedings ArticleDOI
Experimental and Computational Evaluation of Flush-Mounted, S-Duct Inlets
Bobby L. Berrier,Brian G. Allan +1 more
TL;DR: A new high Reynolds number test capability for boundary layer ingesting inlets has been developed for the NASA Langley Research Center 0.3-Meter Transonic Cryogenic Tunnel as discussed by the authors.
Proceedings ArticleDOI
Multidisciplinary Design and Optimization of the Silent Aircraft
TL;DR: The creation, implementation, and use of an integrated design tool to predict and optimize the performance and costs associated with producing a novel, commercial aircraft design with a step change in noise reduction is described.
Ultra-efficient Engine Diameter Study
TL;DR: This study identifies the optimum engine fan diameter and BPR, given the advanced Ultra-Efficient Engine Technology (UEET) powerplant efficiencies, for use on an advanced subsonic airframe.