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  • 1
    Electronic Resource
    Electronic Resource
    A nonlinear inverse simulation technique applied to coaxial rotor helicopter maneuvers (2002)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 74 (2002), S. 525-533 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: As compared with the maneuvering flight studies for single main rotor helicopters, the corresponding studies for coaxial rotor helicopters are relatively poor. In this paper, the maneuvering flight governing equations for coaxial rotor helicopters is established. By introducing induced velocity interference factor analysis, the coaxial rotor aerodynamic interference can be taken into account. With the combination of coaxial rotor helicopter control features and nonlinear inverse simulation technique, the governing equations for maneuvering flight can be solved so as to determine helicopter control input, control force and moment, and helicopter body attitudes which are needed for performing a specified maneuver. Good results of the sample calculations of level turn and lateral jink maneuvers are obtained and simply analyzed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660210420852
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  • 2
    Electronic Resource
    Electronic Resource
    Parachute flying physical model and inflation simulation analysis (2004)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 76 (2004), S. 215-220 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: By means of establishing parachute's flying physical model, four methods (i.e. tiny segment analysis method, inflating distance method, moment method and simulating canopy shape method) are adopted to analyze and calculate the variations of canopy shape and the parameters of parachute inflation. The results are simply analyzed, and the figures of all the results are compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660410526079
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  • 3
    Electronic Resource
    Electronic Resource
    Modeling the unsteady aerodynamic forces of a maneuvering rotor (1999)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 71 (1999), S. 444-450 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The details of predicting the aerodynamic forces of maneuvering helicopter rotors are discussed in this paper. A new approach to modeling the unsteady rotor aerodynamic forces is presented based on the insight into nonuniform induced velocity distribution, inflow dynamics and unsteady airfoil behavior. For a specified maneuver, the rotor control inputs and helicopter flight attitudes during the maneuvering are first obtained using inverse solution technique, and then the unsteady rotor forces are numerically simulated by synthetically applying the vortex theory, dynamic inflow theory and unsteady airfoil aerodynamic models. Good results of the sample calculations of lateral jink and pop-up maneuvers are obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022669910296882
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  • 4
    Electronic Resource
    Electronic Resource
    Mathematical modeling of helicopter aerobatic maneuvers (2004)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 76 (2004), S. 170-178 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: This paper describes the typical maneuvering courses of helicopters with mathematics systematically and presents the formulas and approaches for calculating the dynamics characteristics. A set of generalized equations which govern the kinematics and dynamics of helicopters in maneuvering flight is given. Three aerobatic maneuvers for loop, roll and turn are specially analyzed in detail and the sample calculations are presented. The method established in this paper is of practical significance for aerobatic employment and design of helicopters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660410526033
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  • 5
    Electronic Resource
    Electronic Resource
    Analyses on ducted tail rotor and airfoil aerodynamic characteristics with CFD (2005)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 77 (2005), S. 62-67 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Purpose - To establish a method for the calculations in the field of rotor aerodynamics.Design/methodology/approach - The calculations of the lift-drag characteristics of OAF and NACA63A312 airfoils at low speed are made using Jameson/TVD mixed scheme. By means of finite volume approach for numerical discretization and Runge-Kutta time-stepping advance, Euler/Navier-Stokes equations are solved. Furthermore, a model based on circular tiny segment momentum theory and blade element theory is established to study the thrust and power of ducted tail rotor.Findings - The results of the calculation demonstrate the feasibility of the established method for analyzing ducted tail rotor aerodynamic characteristics.Research limitations/implications - Although the global thrust and power of ducted tail-rotor could be obtained using current method, the exact flow filed (such as shroud pressure field and the flow over fan blade) calculations still rely on the complex three-dimensional CFD technique that should be studied in future.Practical implications - A very useful method for the preliminary design of the ducted tail rotor.Originality/value - By comparing the calculated results with those of relevant experiment, it is proved that the method developed here is suitable for the calculations in the field of rotor aerodynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660510576055
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  • 6
    Electronic Resource
    Electronic Resource
    A new method for predicting rotor wake geometries and downwash velocity field (1999)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 71 (1999), S. 129-135 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new method for predicting rotor wake in low speed and hovering flight is described to investigate the motion of the helical tip vortex. Beginning with the generalized wake model, a semi-empirical correction for the vortex core effect on rotor wake is made and free wake calculation is carried out. As an example of its engineering application, the calculated downwash velocity field along the rocket launch line is presented and simply analysed. In terms of theory, the method developed here may provide of a referable basis for further study the formation mode of the tip vortex and vortex core interior structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022669910261574
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  • 7
    Electronic Resource
    Electronic Resource
    Numerical simulation of gas seal flowfield in an axially staggered configuration (2000)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 72 (2000), S. 447-451 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Labyrinth seals have been used extensively in industrial production. Better prediction of the performance of a labyrinth seal requires that these mechanisms be understood. This cannot be achieved except by investigating the flowfield details. Therefore, a total variation diminishing (TVD) finite volume scheme is applied to the Navier-Stokes equations to obtain gas seal flowfield characteristics of axially staggered configuration in this paper. The calculation results here show the evolution process from unsteady flowfield characterization to steady flow pattern. Also, these new flowfield details may provide referable basis for understanding seal mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660010346884
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  • 8
    Electronic Resource
    Electronic Resource
    Studies of helicopter dynamic stability and control laws (2001)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 73 (2001), S. 132-138 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Studies of the hingeless rotor helicopter dynamic stability and control laws are conducted. A new method is given for the calculation of stability and controllability of a helicopter in flight condition with lateral velocity. First, the rotary wing dynamic model considered is the one of flap-pitch (including the elastic deformation of control system) - torsion coupling. The induced velocity non-uniform distribution derived from vortex theory is taken into account. Then, according to the established motion model of the helicopter, the effects of induced velocity distribution, flap-pitch-torsion coupling and lateral velocity on the stability and controllability of the helicopter are analyzed. Based on the analyses of dynamic stability of the helicopter, the unstable mode and the necessity of installation of stability augmentation system (SAS) are recognized. Finally, the control laws of SAS for helicopter pitching, rolling and yawing motions are presented. After establishing helicopter flight control state equations, the performance analyses and step response simulation for helicopter SAS are carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660110384935
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  • 9
    Electronic Resource
    Electronic Resource
    Studies on damping characteristics and parameter optimization of anisotropic laminated damped structure (2002)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 74 (2002), S. 332-337 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: An anisotropic design is introduced to the laminated damped plates in this paper. The parameter effects on the loss factor of anisotropic laminated damped plates have been analyzed in detail. The damping analyses and control mechanism of laminated anisotropic damped plates have been carried out theoretically. Finally, through the software developed here, the parameter optimization has been conducted on the loss factors of the anisotropic laminated damped plates. The results indicate it may provide scientific basis for the new optimization anisotropic design of laminated damped plates used in Aircraft cabin structure for obtaining the maximum loss factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660210434406
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  • 10
    Electronic Resource
    Electronic Resource
    Nonlinear inverse dynamics control of the aircraft in the presence of windshear (2004)
    Bingley : Emerald
    Aircraft engineering and aerospace technology 76 (2004), S. 592-599 
    Details
    ISSN: 0002-2667
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Control laws that are based on the nonlinear inverse dynamics (NID) of the aircraft offer the potential for providing improved levels of performance over conventional flight control designs. The NID and its application in the flight control during windshear penetration are introduced here. With the employment of a real engineering windshear model and NID, a low-altitude windshear penetration flight control law is designed. The simulative calculation results indicated that the NID control logic works effectively in the trajectory control of the aircraft during the penetration of windshear.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00022660410565517
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