Results 261 to 270 of about 63,330 (315)

Ducted Fan VTOL for Working Platform

SAE Technical Paper Series, 1991
<div class="htmlview paragraph">Making use of advantages of ducted fan, i.e. compactness and approachability, ducted fan VTOL can be used for many purposes, such as construction and servicing of the tall structures, rescue, etc.. In this paper the development of a working platform which utilizes the ducted fan VTOL concept is tried.
Shohei Niwa, Masayuki Suzuki
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Ducted Fan Efficiency and Noise

SAE Technical Paper Series, 2005
<div class="htmlview paragraph">NACA reports from the 1950s and more recently developed CFD codes are used to define features necessary for the creation of an efficient ducted fan system. Sources of ducted fan noise are identified and methods to minimize that noise are outlined. The connection between efficiency and noise is detailed.</div>
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Nondimensional Modeling of Ducted-Fan Aerodynamics

Journal of Aircraft, 2012
The unique aerodynamic nature of the ducted-fan configuration makes it difficult to represent in terms of traditional nondimensional coefficients. Analysis of wind-tunnel data for an axisymmetric generic ducted-fan configuration has led to a new nondimensional modeling scheme. Force coefficients are plotted versus advance ratio for a range of angles of
Osgar John Ohanian, Paul A. Gelhausen, Daniel J. Inman   +2 more
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Evaluation of quad ducted‐fan helicopter

International Journal of Intelligent Unmanned Systems, 2013
PurposeWith the purpose of clearing up the risk to rotor blades, this paper develops a quad ducted‐fan helicopter using four ducted‐fans instead of four rotor blades in a quad rotor helicopter.Design/methodology/approachAuto hovering test, auto cruise test, and altitude control simulations were conducted to estimate the flight performance of the quad ...
Masafumi Miwa, Shinji Uemura, Yasuyuki Ishihara, Akitaka Imamura, Joon‐hwan Shim, Kiyoshi Ioi   +5 more
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Matching fan and motor design parameters in electric ducted fans

Proceedings of Global Power & Propulsion Society
Electric propulsion systems are gaining more research interest as a way to achieve zero-emission aviation. However, scaling up such systems for larger civil aircraft flying at higher flight speeds poses challenges. One major issue is aligning the performance of electric motors with the aerodynamic design of the fan. This paper discusses matching of the
Viacheslav A. Sedunin, James V. Taylor, Sam D. Grimshaw   +2 more
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Unsteady aerodynamic analysis of ducted fans

Journal of Propulsion and Power, 1991
A steady and unsteady aerodynamic analysis of ducted fans has been developed using a frequency domain panel method based on three-dimensional linear compressible lifting surface theory. The duct is assumed to be a finite-length right-circular cylinder concentric with the rotor.
Marc H. Williams, Jinsoo Cho, William N. Dalton   +2 more
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Ducted fan UAV hovering attitude control

Proceedings of 2011 International Conference on Electronic & Mechanical Engineering and Information Technology, 2011
This paper focus on the modeling and control of a small ducted fan unmanned aerial vehicle (UAV). The mathematical model of the hovering flight UAV is established from aerodynamic analysis. Then, a control method for the hovering flight was obtained, which is based on the H ∞ control theory.
Xiao-lu Ren, Chang-hong Wang, Guo-xing Yi   +2 more
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Air Flow in Fan-Discharge Ducts

Journal of Fluids Engineering, 1934
Abstract This paper is concerned with an examination of possible causes of the discrepancies which are sometimes found between pitot-tube measurements and nozzle measurements of the volume of air flowing in a fan-discharge duct. Among the conclusions reached are the following: (1) Air pulsations may cause a small error; (2) Incorrect ...
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Acoustic Isolation of Fans in Ducts

Proceedings of the Institution of Mechanical Engineers, 1966
A method of reducing the sound power radiated downstream from axial flow fans is described and investigated. The normal parallel duct fan housing is replaced by a contoured arrangement. With one type of contour and the use of porous absorbent material the reduction in the downstream overall sound power level is 5 dB, that is, the total sound power is ...
A. W. Roberts, R. E. Luxton
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Noise radiation from ducted fans with realistic duct-rotor coupling

The Journal of the Acoustical Society of America, 1992
The problem of noise radiation from inlet and exhaust of ducted fans is important because of anticipated stringent noise standards. The aerodynamic and duct propagation problems of these engines have been solved. What is needed is the coupling of rotor aerodynamics and duct propagation using realistic physical and geometrical models on today’s high ...
F. Farassat, P. L. Spence
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