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Antonio Filippone - One of the best experts on this subject based on the ideXlab platform.

  • aircraft noise prediction
    Progress in Aerospace Sciences, 2014
    Co-Authors: Antonio Filippone
    Abstract:

    Abstract This contribution addresses the state-of-the-art in the field of aircraft noise prediction, simulation and minimisation. The point of view taken in this context is that of comprehensive models that couple the various aircraft systems with the acoustic sources, the propagation and the Flight trajectories. After an exhaustive review of the present predictive technologies in the relevant fields (airframe, propulsion, propagation, aircraft operations, trajectory optimisation), the paper addresses items for further research and development. Examples are shown for several airplanes, including the Airbus A319-100 (CFM engines), the Bombardier Dash8-Q400 (PW150 engines, Dowty R408 propellers) and the Boeing B737-800 (CFM engines). Predictions are done with the Flight Mechanics code Flight . The transfer function between Flight Mechanics and the noise prediction is discussed in some details, along with the numerical procedures for validation and verification. Some code-to-code comparisons are shown. It is contended that the field of aircraft noise prediction has not yet reached a sufficient level of maturity. In particular, some parametric effects cannot be investigated, issues of accuracy are not currently addressed, and validation standards are still lacking.

  • theoretical framework for the simulation of transport aircraft Flight
    Journal of Aircraft, 2010
    Co-Authors: Antonio Filippone
    Abstract:

    This contribution presents a novel simulation theory for a complete fixed-wing aircraft. Novel methods are presented for Flight Mechanics (fuel planning), turbofan engine simulation (in direct and inverse mode), thermo-physics integration (tire temperature on the ground and fuel temperature in Flight) and aircraft noise. At the fundamental level, the framework presented addresses a shortfall in multi-disciplinary integration in aircraft Flight, including economic operations, preliminary design and environmental emissions. Validation strategies are introduced for component-level analysis and system integration. Results are presented for geometry models, specific air range and optimal cruise conditions, payload-range performance, fuel temperature of a wing tank, tire heating during normal take-off, aircraft propulsive (jet/nozzle) and non propulsive (landing gear) noise. Selected results are shown for the Boeing B777-300 and the Airbus A380-861.

  • comprehensive analysis of transport aircraft Flight performance
    Progress in Aerospace Sciences, 2008
    Co-Authors: Antonio Filippone
    Abstract:

    Abstract This paper reviews the state-of-the art in comprehensive performance codes for fixed-wing aircraft. The importance of system analysis in Flight performance is discussed. The paper highlights the role of aerodynamics, propulsion, Flight Mechanics, aeroacoustics, Flight operation, numerical optimisation, stochastic methods and numerical analysis. The latter discipline is used to investigate the sensitivities of the sub-systems to uncertainties in critical state parameters or functional parameters. The paper discusses critically the data used for performance analysis, and the areas where progress is required. Comprehensive analysis codes can be used for mission fuel planning, envelope exploration, competition analysis, a wide variety of environmental studies, marketing analysis, aircraft certification and conceptual aircraft design. A comprehensive program that uses the multi-disciplinary approach for transport aircraft is presented. The model includes a geometry deck, a separate engine input deck with the main parameters, a database of engine performance from an independent simulation, and an operational deck. The comprehensive code has modules for deriving the geometry from bitmap files, an aerodynamics model for all Flight conditions, a Flight Mechanics model for Flight envelopes and mission analysis, an aircraft noise model and engine emissions. The model is validated at different levels. Validation of the aerodynamic model is done against the scale models DLR-F4 and F6. A general model analysis and Flight envelope exploration are shown for the Boeing B-777-300 with GE-90 turbofan engines with intermediate passenger capacity (394 passengers in 2 classes). Validation of the Flight model is done by sensitivity analysis on the wetted area (or profile drag), on the specific air range, the brake-release gross weight and the aircraft noise. A variety of results is shown, including specific air range charts, take-off weight–altitude charts, payload-range performance, atmospheric effects, economic Mach number and noise trajectories at F.A.R. landing points.

Xinyan Deng - One of the best experts on this subject based on the ideXlab platform.

  • Flight Mechanics and control of escape manoeuvres in hummingbirds i Flight kinematics
    The Journal of Experimental Biology, 2016
    Co-Authors: Bo Cheng, Bret W Tobalske, Donald R Powers, Tyson L Hedrick, Susan M Wethington, George T C Chiu, Xinyan Deng
    Abstract:

    Hummingbirds are nature's masters of aerobatic manoeuvres. Previous research shows that hummingbirds and insects converged evolutionarily upon similar aerodynamic mechanisms and kinematics in hovering. Herein, we use three-dimensional kinematic data to begin to test for similar convergence of kinematics used for escape Flight and to explore the effects of body size upon manoeuvring. We studied four hummingbird species in North America including two large species (magnificent hummingbird, Eugenes fulgens, 7.8 g, and blue-throated hummingbird, Lampornis clemenciae, 8.0 g) and two smaller species (broad-billed hummingbird, Cynanthus latirostris, 3.4 g, and black-chinned hummingbirds Archilochus alexandri, 3.1 g). Starting from a steady hover, hummingbirds consistently manoeuvred away from perceived threats using a drastic escape response that featured body pitch and roll rotations coupled with a large linear acceleration. Hummingbirds changed their flapping frequency and wing trajectory in all three degrees of freedom on a stroke-by-stroke basis, likely causing rapid and significant alteration of the magnitude and direction of aerodynamic forces. Thus it appears that the Flight control of hummingbirds does not obey the 'helicopter model' that is valid for similar escape manoeuvres in fruit flies. Except for broad-billed hummingbirds, the hummingbirds had faster reaction times than those reported for visual feedback control in insects. The two larger hummingbird species performed pitch rotations and global-yaw turns with considerably larger magnitude than the smaller species, but roll rates and cumulative roll angles were similar among the four species.

  • Flight Mechanics and control of escape manoeuvres in hummingbirds ii aerodynamic force production Flight control and performance limitations
    The Journal of Experimental Biology, 2016
    Co-Authors: Bo Cheng, Bret W Tobalske, Donald R Powers, Tyson L Hedrick, Susan M Wethington, George T C Chiu, Yi Wang, Xinyan Deng
    Abstract:

    The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique Flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of manoeuvring performance of hummingbirds 1) muscle mechanical power output and 2) delays in the neural sensing and control system. We focused on the magnificent hummingbird, ( Eugenes fulgens , 7.8g) and black-chinned hummingbird ( Archilochus alexandri , 3.1 g), which represent large and small species, respectively. We first estimated the aerodynamic forces, moments and the mechanical power of escape manoeuvres using measured wing kinematics. Comparing active-manoeuvring and passive-damping aerodynamic moments, we found that pitch dynamics were lightly damped and dominated by effect of inertia while roll dynamics were highly damped. To achieve observed closed-loop performance, pitch manoeuvres required faster sensorimotor transduction, as hummingbirds can only tolerate half the delay allowed in roll manoeuvres. Accordingly, our results suggested that pitch control may require a more sophisticated control strategy, such as those based on prediction. For the magnificent hummingbird, we estimated escape manoeuvres required muscle mass-specific power 4.5 times that during hovering. Therefore, in addition to the limitation imposed by sensorimotor delays, muscle power could also limit the performance of escape manoeuvres.

Tomáš Vogeltanz - One of the best experts on this subject based on the ideXlab platform.

  • A Survey of Free Software for the Design, Analysis, Modelling, and Simulation of an Unmanned Aerial Vehicle
    Archives of Computational Methods in Engineering, 2016
    Co-Authors: Tomáš Vogeltanz
    Abstract:

    The objective of this paper is to analyze free software for the design, analysis, modelling, and simulation of an unmanned aerial vehicle (UAV). Free software is the best choice when the reduction of production costs is necessary; nevertheless, the quality of free software may vary. This paper probably does not include all of the free software, but tries to describe or mention at least the most interesting programs. The first part of this paper summarizes the essential knowledge about UAVs, including the fundamentals of Flight Mechanics and aerodynamics, and the structure of a UAV system. The second section generally explains the modelling and simulation of a UAV. In the main section, more than 50 free programs for the design, analysis, modelling, and simulation of a UAV are described. Although the selection of the free software has been focused on small subsonic UAVs, the software can also be used for other categories of aircraft in some cases; e.g. for MAVs and large gliders. The applications with an historical importance are also included. Finally, the results of the analysis are evaluated and discussed—a block diagram of the free software is presented, possible connections between the programs are outlined, and future improvements of the free software are suggested.

Bo Cheng - One of the best experts on this subject based on the ideXlab platform.

  • Flight Mechanics and control of escape manoeuvres in hummingbirds i Flight kinematics
    The Journal of Experimental Biology, 2016
    Co-Authors: Bo Cheng, Bret W Tobalske, Donald R Powers, Tyson L Hedrick, Susan M Wethington, George T C Chiu, Xinyan Deng
    Abstract:

    Hummingbirds are nature's masters of aerobatic manoeuvres. Previous research shows that hummingbirds and insects converged evolutionarily upon similar aerodynamic mechanisms and kinematics in hovering. Herein, we use three-dimensional kinematic data to begin to test for similar convergence of kinematics used for escape Flight and to explore the effects of body size upon manoeuvring. We studied four hummingbird species in North America including two large species (magnificent hummingbird, Eugenes fulgens, 7.8 g, and blue-throated hummingbird, Lampornis clemenciae, 8.0 g) and two smaller species (broad-billed hummingbird, Cynanthus latirostris, 3.4 g, and black-chinned hummingbirds Archilochus alexandri, 3.1 g). Starting from a steady hover, hummingbirds consistently manoeuvred away from perceived threats using a drastic escape response that featured body pitch and roll rotations coupled with a large linear acceleration. Hummingbirds changed their flapping frequency and wing trajectory in all three degrees of freedom on a stroke-by-stroke basis, likely causing rapid and significant alteration of the magnitude and direction of aerodynamic forces. Thus it appears that the Flight control of hummingbirds does not obey the 'helicopter model' that is valid for similar escape manoeuvres in fruit flies. Except for broad-billed hummingbirds, the hummingbirds had faster reaction times than those reported for visual feedback control in insects. The two larger hummingbird species performed pitch rotations and global-yaw turns with considerably larger magnitude than the smaller species, but roll rates and cumulative roll angles were similar among the four species.

  • Flight Mechanics and control of escape manoeuvres in hummingbirds ii aerodynamic force production Flight control and performance limitations
    The Journal of Experimental Biology, 2016
    Co-Authors: Bo Cheng, Bret W Tobalske, Donald R Powers, Tyson L Hedrick, Susan M Wethington, George T C Chiu, Yi Wang, Xinyan Deng
    Abstract:

    The superior manoeuvrability of hummingbirds emerges from complex interactions of specialized neural and physiological processes with the unique Flight dynamics of flapping wings. Escape manoeuvring is an ecologically relevant, natural behaviour of hummingbirds, from which we can gain understanding into the functional limits of vertebrate locomotor capacity. Here, we extend our kinematic analysis of escape manoeuvres from a companion paper to assess two potential limiting factors of manoeuvring performance of hummingbirds 1) muscle mechanical power output and 2) delays in the neural sensing and control system. We focused on the magnificent hummingbird, ( Eugenes fulgens , 7.8g) and black-chinned hummingbird ( Archilochus alexandri , 3.1 g), which represent large and small species, respectively. We first estimated the aerodynamic forces, moments and the mechanical power of escape manoeuvres using measured wing kinematics. Comparing active-manoeuvring and passive-damping aerodynamic moments, we found that pitch dynamics were lightly damped and dominated by effect of inertia while roll dynamics were highly damped. To achieve observed closed-loop performance, pitch manoeuvres required faster sensorimotor transduction, as hummingbirds can only tolerate half the delay allowed in roll manoeuvres. Accordingly, our results suggested that pitch control may require a more sophisticated control strategy, such as those based on prediction. For the magnificent hummingbird, we estimated escape manoeuvres required muscle mass-specific power 4.5 times that during hovering. Therefore, in addition to the limitation imposed by sensorimotor delays, muscle power could also limit the performance of escape manoeuvres.

Döring, Frederik Alexander - One of the best experts on this subject based on the ideXlab platform.

  • Improving a real time helicopter simulator model with linear input filters
    'Springer Science and Business Media LLC', 2021
    Co-Authors: Scepanovic Pavle, Döring, Frederik Alexander
    Abstract:

    For a broad range of applications, Flight Mechanics simulator models have to accurately predict the aircraft dynamics. However, the development and improvement of such models is a difficult and time consuming process. This is especially true for helicopters. In this paper, two rapidly applicable and implementable methods to derive linear input filters that improve the simulator model are presented. The first method is based on model inversion, the second on feedback control. Both methods are evaluated in the time domain, compared to recorded helicopter Flight test data, and assessed based on root mean square errors and the Qualification Test Guide bounds. The best results were achieved when using the first method

  • Improving a Real-Time Helicopter Simulator Model With Linear Input Filters
    2020
    Co-Authors: Scepanovic Pavle, Döring, Frederik Alexander
    Abstract:

    For a broad range of applications, Flight Mechanics simulator models have to accurately predict the aircraft dynamics. However, the development and improvement of such models is a difficult and time consuming process. This is especially true for helicopters. In this paper, two rapidly applicable and implementable methods to derive linear input filters that improves the simulator model are presented. The first method is based on model inversion, the second on feedback control. Both methods are evaluated in the time domain, compared to recorded helicopter Flight test data, and assessed based on root mean square errors and the Qualification Test Guide bounds. The best results were achieved when using the first method with filter calculated from high-fidelity system identified models