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Dissertations / Theses on the topic 'Flight characteristics'
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1
Larsson, Roger. "System Identification of Flight Mechanical Characteristics." Licentiate thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-92823.
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With the demand for more advanced fighter aircraft, relying on relaxed stability or even unstable flight mechanical characteristics to gain flight performance, more focus has been put on model-based system engineering to help with the design work. The flight control system design is one important part that relies on this modeling. Therefore it has become more important to develop flight mechanical models that are highly accurate in the whole flight envelop. For today’s newly developed fighters, the basic aircraft characteristics change between linear and nonlinear as well as stable and unstable as an effect of the desired capability of advanced maneuvering at subsonic, transonic and supersonic speeds. This thesis combines the subject of system identification, which is the art of building mathematical models of dynamical systems based on measurements, with aeronautics in order to find methods to identify flight mechanical characteristics from flight tests. Here, a challenging aeronautical identification problem combining instability and nonlinearity is treated. Two aspects are considered. The first is identification during a flight test with the intent to ensure that enough information is available in the resulting test data. Here, a frequency domain method is used. This idea has been taken from an existing method to which some improvements have been made. One of these improvements is to use an Instrumental Variable approach to take care of disturbances coming from atmospheric turbulence. The method treats linear systems that can be both stable and unstable. The improved method shows promising results, but needs further work to become robust against outliers and missing data. The other aspect is post-flight identification. Here, five different direct identification methods, which treat unstable and nonlinear systems, have been compared. Three of the methods are variations of the prediction-error method. The fourth is a parameter and state estimation method and the fifth method is a state estimation method based on an augmented system approach. The simplest of the prediction-error methods, based on a parametrized observer approach, is least sensitive to noise and initial offsets of the model parameters for the studied cases. This approach is attractive since it does not have any parameters that the user has to tune in order to get the best performance. All methods in this thesis have been validated on simulated data where the system is known, and have also been tested on real flight test data.
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Kornienko, Andrei. "System identification approach for determining flight dynamical characteristics of an airship from flight data." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-28803.
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Soinne, Erkki. "Aerodynamic and Flight Dynamic Simulations of Aileron Characteristics." Doctoral thesis, KTH, Aeronautical Engineering, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3038.
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Hazlehurst, Grant Allen. "The morphometric and flight characteristics of the pterosaurs." Thesis, University of Bristol, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303761.
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Yin, Feijia, Volker Grewe, Christine Frömming, and Hiroshi Yamashita. "Impact on flight trajectory characteristics when avoiding the formation of persistent contrails for transatlantic flights." Elsevier, 2018. https://publish.fid-move.qucosa.de/id/qucosa%3A72194.
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This paper studies the impacts on flight trajectories, such as lateral and vertical changes, when avoiding the formation of persistent contrails for transatlantic flights. A sophisticated Earth-System Model (EMAC) coupled with a flight routing submodel (AirTraf) and a contrail submodel (CONTRAIL) is used to optimize flight trajectories concerning the flight time and the flight distance through contrail forming regions (contrail distance). All the trajectories are calculated taking into account the effects of the actual and local meteorological parameters, e.g., wind, temperature, relative humidity, etc. A full-year simulation has been conducted based on a daily flight schedule of 103 transatlantic flights. The trade-off between the flight time and contrail distance shows a large daily variability, meaning for the same increase in flight time, the reduction in contrail distance varies from 20% to 80% depending on the daily meteorological situation. The results confirm that the overall changes in flight trajectories follow a seasonal cycle corresponding to the nature of the potential contrail coverage. In non-summer seasons, the southward and upward shifts of the trajectories are favorable to avoid the contrail formation. In summer, the northward and upward shifts are preferred. A partial mitigation strategy for up to 40% reduction in contrail distance can be achieved throughout all the seasons with a negligible increase in flight time (less than 2%), which represents a reasonable trade-off between flight time increase and contrail avoidance.
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Neiusma, William J. Jr. "An investigation of two-propeller tilt wing V/STOL aircraft flight characteristics." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/39820.
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Approved for public release, distribution is unlimitedThe results of a two-propeller tilt wing aircraft static stability and performance simulation utilizing a NASA-Ames computer code, Tilt Wing Application General (TWANG), are presented with comparisons to actual test flight data. The Canadair CL-84 tilt wing aircraft was used as a model for the geometric data utilized by the computer simulation. Aerodynamic data for the simulation were obtained from previous NASA Ames research related to a four-propeller model. Variables used included a wide range of parameters associated with flight conditions from hovering flight to maximum cruise speeds at several different altitudes and wing tilt configurations. Longitudinal pitch stability was the driving factor in determining aircraft static stability for the various flight conditions. Results of the simulation indicate that the TWANG computer code provides an accurate prediction of both generic and specific tilt wing aircraft static pitch performance characteristics, as well as the additional capability of providing the required mathematical parameters for incorporation into the NASA Ames Vertical Motion Simulator as software inputs.
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Neiusma, William J. "An investigation of two-propeller tilt wing V/STOL aircraft flight characteristics." Monterey, California : Naval Postgraduate School, 1993. http://handle.dtic.mil/100.2/ADA257751.
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Thesis (Aeronautical and Astronautical Engineer)--Naval Postgraduate School, June 1993.Thesis Advisor: Newberry, Conrad F. "June, 1993." Description based on title screen as viewed on April 16, 2009. Includes bibliographical references (p. 78-79). Also available in print.
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Hrabovský, Matúš. "Posouzení letových vlastností a zatížení malého sportovního letounu po modifikaci pohonné jednotky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417471.
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The thesis deals with the issue of replacement of the Rotax 912 ULS engine with the Rotax 915 iSc3 B engine and its impact on flight performance, characteristics and airframe loads of the WT 9 Dynamic. For accomplish better maneuverability tail surfaces are enlarged. Both versions of airplane with different engines and tails surfaces are quantified with respect to airframe loads and flight characteristics. The output of the diploma thesis can be used for strength design of airplane structure and stress tests of the new modification of the WT 9 Dynamic aircraft.
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Lewis, William D. "An aeroelastic model structure investigation for a manned real-time rotorcraft simulation." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/13037.
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Min, Byung-Young. "A physics based investigation of gurney flaps for enhancement of rotorcraft flight characteristics." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33851.
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Helicopters are versatile vehicles that can vertically take off and land, hover, and perform maneuver at very low forward speeds. These characteristics make them unique for a number of civilian and military applications. However, the radial and azimuthal variation of dynamic pressure causes rotors to experience adverse phenomena such as transonic shocks and 3-D dynamic stall. Adverse interactions such as blade vortex interaction and rotor-airframe interaction may also occur. These phenomena contribute to noise and vibrations. Finally, in the event of an engine failure, rotorcraft tends to descend at high vertical velocities causing structural damage and loss of lives.
A variety of techniques have been proposed for reducing the noise and vibrations. These techniques include on-board control (OBC) devices, individual blade control (IBC), and higher harmonic control (HHC). Addition of these devices adds to the weight, cost, and complexity of the rotor system, and reduces the reliability of operations. Simpler OBC concepts will greatly alleviate these drawbacks and enhance the operating envelope of vehicles.
In this study, the use of Gurney flaps is explored as an OBC concept using a physics based approach. A three dimensional Navier-Stokes solver developed by the present investigator is coupled to an existing free wake model of the wake structure. The method is further enhanced for modeling of Blade-Vortex-Interactions (BVI). Loose coupling with an existing comprehensive structural dynamics analysis solver (DYMORE) is implemented for the purpose of rotor trim and modeling of aeroelastic effects.
Results are presented for Gurney flaps as an OBC concept for improvements in autorotation, rotor vibration reduction, and BVI characteristics. As a representative rotor, the HART-II model rotor is used.
It is found that the Gurney flap increases propulsive force in the driving region while the drag force is increased in the driven region. It is concluded that the deployable Gurney flap may improve autorotation characteristics if deployed only over the driving region. Although the net effect of the increased propulsive and drag force results in a faster descent rate when the trim state is maintained for identical thrust, it is found that permanently deployed Gurney flaps with fixed control settings may be useful in flare operations before landing by increasing thrust and lowering the descent rate.
The potential of deployable Gurney flap is demonstrated for rotor vibration reduction. The 4P harmonic of the vertical vibratory load is reduced by 80% or more, while maintaining the trim state. The 4P and 8P harmonic loads are successfully suppressed simultaneously using individually controlled multi-segmented flaps.
Finally, simulations aimed at BVI avoidance using deployable Gurney flaps are also presented.
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Abramov, Nikolay. "Modelling of unsteady aerodynamic characteristics for aircraft dynamics applications at high incidence flight." Thesis, De Montfort University, 2005. http://hdl.handle.net/2086/4108.
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A traditional representation of aerodynamic characteristics based on the concept of aerodynamic derivatives fails to be accurate at high angles of attack due to significant dynamic effects generated from separated and vortical flow. As the possibility of performing controlled flight at high angles of attack has already become a common requirement for modern combat aircraft, the problem of an adequate model for aerodynamic loads at high incidences is the issue of the day. This thesis presents a phenomenological approach to modelling of unsteady aerodynamic characteristics at high angles of attack. In this approach aerodynamic characteristics are considered as a combination of two components having different characteristic time scales which describe the contribution to the total aerodynamic load from the different flow structures. It is assumed that all dynamic properties of the flow are amassed in the' slow' component. To describe its behaviour specially designed nonlinear differential equations are used. Depending on the parameters, this model can reproduce both 'weak' and 'strong' nonlinear effects including static hysteresis. A special identification technique has been developed for the estimation of the model parameters using dynamic wind tunnel test data.
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Tyson, Peter H. "Simulation validation and flight prediction of UH-60A Black Hawk helicopter/slung load characteristics." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1999. http://handle.dtic.mil/100.2/ADA362524.
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Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School, March 1999."March1999". Thesis advisor(s): E. Roberts Wood, Mark B. Tischler. Includes bibliographical references (p. 279-281). Also available online.
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Elgin, Ross Alexander [Verfasser], and Wolfgang [Akademischer Betreuer] Stinnesbeck. "Palaeobiology, Morphology, and Flight Characteristics of Pterodactyloid Pterosaurs / Ross Alexander Elgin ; Betreuer: Wolfgang Stinnesbeck." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180299698/34.
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Hess, Marc Frederick. "Flight characteristics of pen-reared and wild prairie-chickens and an evaluation of a greenhouse to rear prairie-chickens." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/163.
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The introduction of pen-reared Attwater's prairie-chickens (APC, Tympanuchus cupido attwateri) into the wild to supplement existing populations has met with marginal success. Flight characteristics, predator avoidance behavior, and rearing methods are possible factors contributing to post-release mortality of pen-reared birds. To evaluate flight characteristics and predator avoidance behavior of pen-reared APC's released onto the Attwater Prairie Chicken National Wildlife Refuge, flight characteristics and predator avoidance behavior of pen-reared APC's was compared to wild greater prairie-chickens (GPC, T. c. pinnatus) in Minnesota and Kansas using a radar gun and a trained dog. There was no difference (P = 0.134) in flight speed for pen-reared APC and wild GPC. However, wild GPC had greater (P < 0.001) flight distances than did pen-reared APC. Wild GPC and pen-reared APC that had survived in the wild for at least a year flushed at a greater (P < 0.001) distance from an approaching human than did pen-reared APC that had been released for less than 3 months. A trained dog was able to approach closer (P < 0.001) to APC than GPC before birds flushed, and APC did not fly as far as GPC after being flushed by the dog. Pen-reared APC displayed flight endurance deficiencies and were more approachable by humans and a dog before they flushed when compared to wild GPC, which could explain their increased mortality when released into the wild. To determine if APC chicks could be reared without daily human contact, pelleted food, and water in founts, a greenhouse was used to rear chicks in a semi-natural environment. Planted vegetation and commercial insects provided hiding cover and a food source for the APC chicks. An underground heat source provided chick warmth, and water misters and a sprinkler system simulated dew (a water source for chicks) and rain. The greenhouse provided chicks protection from predators and adverse weather conditions (before they could thermo-regulate) while exposing chicks to natural sunlight, day length, and temperature fluctuations. This technique allowed chicks to be reared in a semi-natural environment which reinforced their natural foraging behavior for food and water, and reinforced their hiding and avoidance behaviors, creating a wilder pen-reared bird.
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McVaney, Gary P. "Procedural guide for modelling and analyzing the flight characteristics of a helicopter design using Flightlab." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA275077.
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Thesis (M.S. in Aeronautical Engineering) Naval Postgraduate School, September 1993.Thesis advisor(s): Wood, E. Roberts. "September 1993." Includes bibliographical references. Also available online.
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Oliver, Michael 1981. "A parametric analysis of the start-up procedure and flight characteristics of a gliding autogyro." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/28910.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2005."CSDL-T-1503, digital appendix"--CDROM label. Appendix B of thesis text contains an index to the CDROM.
Includes bibliographical references (p. 113-114).
Currently, Draper Laboratory is in the development stages of a gliding autogyro airdrop system. The goal of the project is to design a platform capable of placing small, high value items into urban terrain. Theoretically, autogyros can achieve descent rates and glide slopes similar to current parafoil based systems, but do so with greater precision. Over the past half-century most rotorcraft research has focused on helicopter design, only viewing autorotation as a means of achieving emergency landings. In contrast, this project utilized early rotor theory to develop algorithms which can predict unpowered rotor performance across the entire flight envelope. To validate these predictions, a vertical wind tunnel capable of testing rotors up to 4 feet in diameter at descent rates of up to 25 ft/s was constructed. Emphasis was also placed on developing deployment sequences that would allow the system to achieve stable autorotation autonomously. By varying parameters such as blade pitch angle and rotor solidity, it is shown that in the proper configuration, rotor based systems can match and even surpass parafoils in areas such as descent rate and glide slope. The autogyro also has the added capability of varying its lift-to-drag ratio in flight while maintaining reasonable descent speeds, allowing for more precise control to the target. Possible deployment sequences are displayed, proving that relatively simple configurations can be brought into stable autorotation. The algorithms developed and vertical wind tunnel constructed for this project can be used to gain further knowledge of autogyro performance.
by Michael Oliver.
S.M.
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Keesey, Ian W. "The seasonal occurrence, soil distribution and flight characteristics of Curculio sayi (Coleoptera: Curculionidae) in mid-Missouri." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5028.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on November 11, 2008) Includes bibliographical references.
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Brown, T. Gordon, Ed Bukowski, Mark Ilg, and Fred Brandon. "MEASUREMENT OF IN-FLIGHT MOTION CHARACTERISTICS OF A HIGH-G LAUNCHED FLARESTABILIZED PROJECTILE WITH ON-BOARD TELEMETRY." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604268.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaIn pursuit to understanding the flight behavior and characterizing the stability of a flarestabilized projectile, an experiment was conducted to assess the robustness of an inertial sensor suite the size of a dime (17.5mm) by integrating to a telemetry system for recording. The system had to survive launch acceleration exceeding 25,000G’s. This is the beginning of an effort to reduce the size of telemetry systems and diagnostic devices for use in medium caliber munitions and smaller. A description of the telemetry system and subsystem will be presented along with the results.
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Sugio, Koji. "Damage on living trees and ecological characteristics of the Ryukyu drywood termite, Neotermes sugioi Yashiro in Okinawa Island." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/263359.
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Heise, Christian David [Verfasser], Florian [Akademischer Betreuer] Holzapfel, Boris [Gutachter] Lohmann, and Florian [Gutachter] Holzapfel. "Survivable Flight Control with Guaranteed Stability and Performance Characteristics / Christian David Heise ; Gutachter: Boris Lohmann, Florian Holzapfel ; Betreuer: Florian Holzapfel." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1149776617/34.
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Zambujal, Ricardo Miguel Santinhos. "Fadiga ocupacional e processos de regulação emocional: Um estudo exploratório com tripulantes de cabine." Master's thesis, ISPA - Instituto Universitário, 2013. http://hdl.handle.net/10400.12/2739.
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Dissertação de Mestrado em Psicologia Social e das Organizações apresentada ao ISPA - Instituto UniversitárioO presente estudo pretende fornecer evidências empíricas das potenciais consequências da organização dos horários de trabalho, das caraterísticas do trabalho e das experiências de recuperação nos níveis de fadiga percepcionados no início e no final do PSV. A literatura evidencia como indicadores da fadiga ocupacional: a distinção entre voos de NB e WB, o planeamento da escala de trabalho, a “dívida” de sono e a duração do período de tempo em que se está acordado. Um total de 51 tripulantes de cabine participaram neste estudo, transversalmente em 82 PSV categorizados em NB e WB. Para avaliar a fadiga ocupacional utilizou-se o CIS (Bultmann et al., 2000; D’Oliveira, 2012), a Fadiga Samn-Perelli (Samn & Perelli, 1982) e a Sonolência Karolinska (Åkerstedt & Gillbert, 1990). Para medir as experiências de recuperação a The Recovery Experience (Sonnentag & Fritz, 2007; D’Oliveira, 2012). Os resultados explanam o efeito e associação das variáveis inerentes ao contexto de trabalho nas medidas de fadiga ocupacional. Verificou-se que o modelo de investigação proposto, identifica a disrupção do ritmo circadiano (causada por despertares cedo e voos noturnos), o período de tempo acordado (vigília) e as experiências de recuperação como principais indicadores de fadiga ocupacional nos dois momentos de mensuração. Não existiu uma diferenciação estatisticamente significativa entre os voos categorizados, NB e WB. Verificou-se que o distanciamento psicológico é preditor da Fadiga Samn-Perelli no momento inicial; e que a Fadiga Samn-Perelli reportada no momento final tem como preditores a duração do PSV e a Fadiga Samn-Perelli no momento inicial.
ABSTRACT: This study aims to provide empirical evidences regarding the potential consequences of non-standard work schedules, job characteristics and recovery experiences in the perceived fatigue levels at the beginning and end of PSV. The literature suggests the distinction between NB and WB flights, the rostering, sleep debt and wakefulness as occupational fatigue indicators. A total of 51 flight attendants participated in this study across 82 PSV categorized in NB and WB. To assess the occupational fatigue it was used CIS (Bultmann et al., 2000; D’Oliveira, 2012), Fatigue Samn-Perelli (Samn & Perelli, 1982) and Karolinska Sleepiness Scale (Åkerstedt & Gillbert, 1990). To measure recovery experiences it was used The Recovery Experience Scale (Sonnentag & Fritz, 2007; D’Oliveira, 2012). The findings show the effect and association of variables inherent to the working context in measuring occupational fatigue. It has been found that the proposed research model identifies the circadian disruption (caused by early-birds and late calls), the extended wakefulness and recovery experiences, as key indicators of occupational fatigue in both measurement moments. There was not a significant statistical difference between flights, NB and WB. It was found that psychological detachment is a predictor of subjective fatigue Samn-Perelli in the initial moment. Both, subjective fatigue Samn-Perelli (initial moment) and time length of the PSV are predictors of fatigue levels (Samn-Perelli) in the final moment.
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Read, Michael Leonard. "The impact of material surface characteristics on the clinical wetting properties of silicone hydrogel contact lenses." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-impact-of-material-surface-characteristics-on-the-wetting-properties-of-silicone-hydrogel-contact-lenses(f9052c88-3fe8-4467-8cda-7feb5b63c066).html.
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This PhD project investigated the ramifications of air-cured and nitrogen-cured manufacturing processes during silicone hydrogel contact lens manufacture in terms of lens surface characterisation and clinical performance. A one-hour contralateral clinical study was conducted for ten subjects to compare the clinical performance of the two study lenses. The main clinical findings were reduced levels of subjective performance, reduced surface wettability and increased deposition. Contact angle analysis showed the air-cured lenses had consistently higher advancing and receding contact angle measurements, in comparison with the nitrogen-cured lens. Chemical analysis of the study lens surfaces in the dehydrated state, by x-ray photoelectron spectroscopy (XPS) and time-of-flight mass spectrometry (ToF-SIMS), showed no difference due to surface segregation of the silicone components. Analysis of frozen lenses limited surface segregation and showed a higher concentration of silicone polymer components and lower concentration of hydrophilic polymer components at the surface of the air-cured lens, in comparison with the nitrogen-cured lens. Scanning electron microscope (SEM) imaging showed the nitrogen-cured lens to have a surface typical of a hydrogel material, whereas the air-cured lens had regions of apparent phase separation. In addition, atomic force microscopy (AFM) showed the air-cured lens to have a rougher surface associated with greater adherence of contaminants (often observed in materials with reduced polymer cross-linking). In conclusion, clinical assessment of the study lenses confirmed the inferior performance of the air-cured lens. Surface analysis suggested that the non-wetting regions on the air-cured lenses were associated with elevated level of silicone components, reduced polymer cross-linking and polymer phase separation.
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Kochtík, Martin. "Stabilita a řiditelnost letounu Z-143 s výkonnější pohonnou jednotkou." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-319252.
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The thesis deals with the calculation and evaluation of the flight characteristics of the aeroplane Z 143 with the power unit Lycoming AEIO-580-B1A. The first part of the text focuses on a general description of the aircraft, its geometric characteristics and calculation of mass and aerodynamic characteristics. In terms of flight performance there are compared the values for contemporary model and developmental aircraft with a more powerful engine. Another part of the work deals with the calculation of properties in terms of stability and manageability. In this section regards the determination of the results of the flight characteristics and their assessment of whether they comply. In the end I discuss the individual results and comment the possible recommendations on correction or improvement of these properties.
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Jurkštas, Kęstutis. "Sklandytuvo svorio centro padėties įtakos skrydžio charakteristikai analizė." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2011. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2011~D_20110830_152339-05498.
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Standartinės klasės sklandytuvo SZD – 48 – 3 “Jantar Standard 3” optimalios svorio centro padėties radimas. Pateikta skaičiavimai optimaliai svorio centro padėčiai surasti bei jos kitimas kintant greičiui.The objective of this Master thesis is to investigate the glider gravity centre influence to the flight characteristics. Analyzing Frank Irving method, to find optimal centre of gravity. The subject of thesis is Standard class glider SZD – 48 – 3 “Jantar Standard 3”and calculation of optimal center of gravity position.
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Zikmund, Pavel. "Identifikace aerodynamických charakteristik atmosférického letadla z výsledků letových měření." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-234162.
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The thesis deals with aerodynamic characteristics identification from flight measurement. The topic is part of flight mechanic – handling qualities. The first theoretic part consists of three identification methods description: Error equation method, Output error method and Filter error method. Mathematical model of an airplane is defined and restricted to the motion with 3 degree of freedom. There is also introduced simulation of flight measurement for identification software validation. Practical part is focused on experiment preparation, execution and evaluation. The airplane VUT 700 Specto had been chosen to carry out flight tests. The airplane was modified to the new electric powered VUT 700e Specto after first measurement flights with combustion engine. Data record from on-board measurement unit was completed by telemetric data from autopilot and remote control system. Flight tests were carried out in stabilised mode of autopilot in symmetric flight. The results were confronted with analytical analysis results and DATCOM+ software parameter estimation.
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Montezuma, Marcio Aurélio Furtado. "Metodologia para identificação e controle de um protótipo de uma plataforma de movimento com 2 G.D.L." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-11012011-143451/.
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Devido à dificuldade em se desenvolver um sistema de controle baseado no modelo da planta, principalmente quando a mesma possui diversos graus de liberdade, busca-se uma metodologia a fim de minimizar o tempo e os esforços para projetar o sistema de controle. A metodologia consiste na utilização de um software de sistemas multicorpos, para a geração do conjunto de equações que descrevem o comportamento dinâmico, a partir de características físicas do sistema, tais como: massa, centro de massa, momentos principais de inércia, dimensões dos elos e juntas com determinados graus de liberdade. Para determinação das características físicas, são utilizadas técnicas experimentais, procedimentos e instrumentação para identificação com acuracidade controlada dos centros de massa e dos momentos principais de inércia dos elos. Estes são considerados corpos rígidos não homogêneos, algumas vezes acoplados por juntas de movimento, não sendo possível desacoplá-los. O sistema de controle utiliza um sistema com realimentação de estados com observador, capaz de fornecer resultados satisfatórios. O observador é utilizado para diminuir o número de estados medidos, facilitando a instrumentação do mecanismo. Esses procedimentos podem ser aplicados à maioria dos sistemas multicorpos, com muitos graus de liberdade, a fim de se obter um sistema de controle com desempenho e acuracidade predefinidos, para serem implementados em sistemas de aquisição e controle flexíveis, ou através de hardwares dedicados. Para validar essa metodologia, esta será aplicada ao protótipo de uma plataforma de movimento que, por conveniência de projeto, teve seus graus de liberdade controlados limitados a dois. Seu acionamento dá-se por servomotores brushless, atuadores de fusos de esferas, utilizando-se sensores de posição linear por magnetostrição e angular ópticos. O fato do número de graus de liberdade ter sido reduzido a dois não invalida a metodologia, caso seja necessário aplicá-la a sistemas com qualquer número de graus de liberdade.The difficulty to develop a control system based in the model of the plant, mainly when the plant has many degrees of freedom, motivated this work which presents a methodology to minimize the time and effort in developing the control system. The methodology consists on the use of a multibody systems software for generating the set of equations that describes the system dynamic behavior, starting from its physical characteristics such as mass, center of mass, principal moments of inertia, dimensions of the links and joints with certain degrees of freedom coupling the links. For the physical characteristics determination, experimental techniques, procedures and instrumentation are used to identify, with controlled accuracy, the links centers of mass and principal moments of inertia, being the plant considered formed by non homogeneous rigid bodies, sometimes coupled by joints of movement and not being possible to uncouple them. For the control system a state feedback control system with estimator is used, capable of suppling satisfactory results. An estimator is used to reduce the number of measured states facilitating the mechanism instrumentation. Those procedures can be applied to most of multibody systems with several degrees of freedom to obtain a control system with performance and accuracy previously defined to be implemented in a flexible acquisition and control board or dedicated hardware. To validate this methodology, it will be applied to a prototype of a movement platform, which, for project convenience had their controlled degrees of freedom limited to two. The platform is driven by brushless servomotors, has actuators with spindle bearings, using sensors of linear position by magnetostriction and angular by optical principle. The fact of the number of degrees of freedom being reduced to two doesn\'t invalidate the methodology in case it is necessary to apply it to systems with any number of degrees of freedom.
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Sumer, Yalcin Faik. "Predictive Control of Multibody Systems for the Simulation of Maneuvering Rotorcraft." Thesis, Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/6940.
Full textAbstract:
Simulation of maneuvers with multibody models of rotorcraft vehicles is an important research area due to its complexity. During the maneuvering flight, some important design limitations are encountered such as maximum loads and maximum turning rates near the proximity of the flight envelope. This increases the demand on high fidelity models in order to define appropriate controls to steer the model close to the desired trajectory while staying inside the boundaries. A framework based on the hierarchical decomposition of the problem is used for this study. The system should be capable of generating the track by itself based on the given criteria and also capable of piloting the model of the vehicle along this track. The generated track must be compatible with the dynamic characteristics of the vehicle. Defining the constraints for the maneuver is of crucial importance when the vehicle is operating close to its performance boundaries.
In order to make the problem computationally feasible, two models of the same vehicle are used where the reduced model captures the coarse level flight dynamics, while the fine scale comprehensive model represents the plant. The problem is defined by introducing planning layer and control layer strategies. The planning layer stands for solving the optimal control problem for a specific maneuver of a reduced vehicle model. The control layer takes the resulting optimal trajectory as an optimal reference path, then tracks it by using a non-linear model predictive formulation and accordingly steers the multibody model. Reduced models for the planning and tracking layers are adapted by using neural network approach online to optimize the predictive capabilities of planner and tracker.
Optimal neural network architecture is obtained to augment the reduced model in the best way. The methodology of adaptive learning rate is experimented with different strategies. Some
useful training modes and algorithms are proposed for these type of applications. It is observed that the neural network increased the predictive capabilities of the reduced model in a robust way.
The proposed framework is demonstrated on a maneuvering problem by studying an obstacle avoidance example with violent pull-up and pull-down.
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Bongo, Njeng Alex Stéphane. "Experimental study and modeling of hydrodynamic and heating characteristics of flighted rotary kilns." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2015. http://www.theses.fr/2015EMAC0009/document.
Full textAbstract:
Ce travail porte sur l'étude de fours tournants équipés de releveurs. Ce sont des contacteurs gaz/solide largement répandus dans de nombreux secteurs industriels mettant en oeuvre des solides divisés. Cependant en raison d'une faible connaissance du fonctionnement de ces équipements notamment en matière d'écoulement ou de transfert thermique, leur utilisation repose encore beaucoup sur le savoir faire des opérateurs acquis avec le temps. Ainsi ce travail vise à fournir aux ingénieurs des outils de connaissance et d'extrapolation pour les accompagner dans les phases de dimensionnement, mais aussi d'optimisation de procédés existants, en particulier pour des fours tournants en chauffage indirect et équipés de releveurs. La première partie de cette étude porte sur l'influence des conditions opératoires sur l'hydrodynamique des solides divisés de forme et taille différentes. Pour ce faire, des procédures expérimentales pour la mesure de distribution des temps de séjours des particules solides ont été mises en oeuvres. Deux pilotes de four tournant ont été utilisés. Ces derniers ont un ratio longueur sur diamètre équivalent mais un ratio de taille de 2. L'hydrodynamique des fours a été caractérisée quantitativement à partir des résultats expérimentaux en terme de temps de séjour des solides, taux de remplissage du four ainsi que de la dispersion axiale des particules. Ces derniers ont été modélisés par analyse dimensionnelle dans un souci de généralité en prenant en compte la présence d'éléments internes (releveurs, grille) ou diaphragmes en sortie, mais aussi des paramètres opératoires tels que la vitesse de rotation du tube, son inclinaison ou le débit des particules solides. La seconde partie de cette étude s'intéresse aux processus de transfert thermique dans les fours tournants en chauffage indirect et équipés de releveurs. Cette étude repose sur la mesure des profils de température à la paroi, dans la phase gazeuse et le lit de particules solides. L'analyse de ces profils de température se focalise sur la détermination des coefficients de transfert de chaleur entre la paroi et le lit de solides d'une part, et entre la paroi et le gaz d'autre part. Une méthode d'analyse globale de système mince et un bilan global intégrant la puissance fournie pour la chauffe sont utilisés pour la détermination de ces coefficients de transfert. Les résultats obtenus permettent d'une part de mettre en évidence l'effet des releveurs ainsi que l'influence des paramètres opératoires sur ces coefficients de transfert de chaleur et d'autre part d'établir par analyse dimensionnelle des modèles pour ces derniers. Enfin, ce travail se termine par la mise en place d'un modèle dynamique simplifié de four tournant en chauffage indirect permettant la détermination des profils de température le long du four et pouvant être facilement adapté à divers procédésThe present work addresses a fundamental study on flighted rotary kilns. They are gas-solid reactors, used in a variety of industries to process heterogeneous media. However, operating these kilns mainly relies on the know-how of operators due to insufficient fundamental understanding. The aim of this work is to provide engineers with relevant tools and models to assist in the design stage and the performance improvement of existing operating process units, in particular indirectly heated rotary kilns, inclined and equipped with lifters. In the first part, we studied the effects of operating parameters on the flow of materials of differing properties and shape. For this purpose, residence time distribution measurements were performed through experimental stimulus response tests. Two pilot-scale rotary kilns with similar length-to-diameter ratios, but a dimension ratio of about two were used in this study. We focused on the effects of lifter shape and configurations. The effects of the rotational speed, the kiln slope, the mass flow rate and the exit dam height were also analyzed. The flow of solids was quantitatively characterized primarily by the experimental mean residence time, hold-up, and axial dispersion coefficient. Using a dimensional analysis, models were established to predict the mean residence time, the filling degree and the axial dispersion coefficient, providing basic information on the kiln design, solid particle properties and operating conditions. In the second part, we studied the heat transfer mechanisms occurring in the flighted rotary kiln by measuring temperature profiles at the wall, the freeboard gas and the bulk of solids. Analysis of the temperature profiles focused on two main issues: assessment of the heat transfer coefficient between wall and gas, and assessment of the heat transfer coefficient between wall and solid particles. The lumped system analysis and a heat balance using the power supplied for the heating were applied to determine the experimental heat transfer coefficients. The effects of operating conditions and lifting flights were analyzed. Both heat transfer coefficients were then correlated through dimensional considerations. Lastly a global dynamic model mainly based on the models developed in this study can be used to determine wall, gas and bulk solids axial temperature profiles in an indirectly heated flighted rotary kiln. This global model needs to be completed with specific models related to a reaction so as to be used as a framework for the simulation of specific industrial rotary kilns
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林肖明 and Chiu-ming Lam. "Visualization studies on the dynamic processing characteristics of conventional full-flighted and barrier type single-screws." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31222845.
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Lam, Chiu-ming. "Visualization studies on the dynamic processing characteristics of conventional full-flighted and barrier type single-screws /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B21904182.
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Yu-HungLin and 林育宏. "Study on Flight Characteristics of Swietenia macrophylla Seeds." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/84cy67.
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Chin-ChiehLin and 林俊杰. "Flight Characteristics Comparison between Quadrotor and Conventional Helicoptor." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/85160914896499690123.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩士在職專班
102
In recent years, research of quadrotors helicopter becomes more and more popular, and often seen in news pages, mentioned it as good stability characteristics, good payload capacity and so on. However, what are the characteristics of quadrotors and conventional helicopter? When and how should they be used? These questions need further exploration, which is also the focus of this thesis. Then the author compares the characteristics of quadrotor and conventional helicopter through a series of actual flight tests by using an unmanned quadrotor and a conventional RC helicopter, which the diameter of helicopter main rotor is equal to the outside dimension of quadrotor. Through this study, it shows that the performance of helicopter is better in payload (2 times larger) than quadrotor, but the efficiencies are almost the same. Helicopter also has better performance in operation duration, power variety (engine or electricity). However, quadrotor has more advantages in low vibration, low noise, easy control, as well as design flexibility. A particular feature is its sustainable to the updraft for helicopter, which has very difficult for quadrotor.
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Chang, Feng-Yao, and 張峰垚. "A study on water rocket dynamic characteristics in flight." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/44917541876573974190.
Full textAbstract:
碩士中原大學
機械工程研究所
104
This study theoretically explores the flight trajectory and dynamic characteristics of water rockets. Its main purpose is to analyze the effects of the inner air pressure and water amount of water rockets on its change of vertical flight altitude, velocity and acceleration over time. The Reynolds transport theorem is first used in the analysis to deduce the momentum conservation equation of water rockets. Then the continuity equation, Bernoulli equation, and the isentropic process relation are applied to infer the outlet fluid velocity and the relationship between the inner air pressure and water amount. Finally, through a numerical solution method, the initial value problem for water rocket space flight and dynamics is solved to predict the flight trajectory and dynamic characteristics, like the vertical flight altitude, velocity and acceleration of water rockets. Moreover, the numerical predictions can be compared with experimental data. The study results on a single-stage water rocket show that the numerical predictions can get the results close to the experimental data. The results further indicate that under a certain water amount in a single-stage water rocket, the greater the air pressure in the rocket, the higher the vertical flight altitude, the faster the maximum velocity and the bigger the maximum acceleration of the rocket. Moreover, under a certain air pressure in a single-stage water rocket, with the increase of water amount in the rocket, the vertical flight altitude increases, the maximum velocity becomes faster, but the maximum acceleration decreases at the beginning stage; however, after more than a certain amount of water, the vertical flight altitude reduces and the maximum velocity becomes slow. As to a double-stage water rocket, the numerical predictions can also get the results near to the experimental data. Furthermore, the capability of the one-way check valve between the upper part and lower part of the double-stage water rocket is an important factor to influence the flight trajectory and dynamic characteristics of the double-stage water rocket. Under a certain total water amount and air pressure, through an appropriate ratio of the water amount adjusted in the upper part and lower part of the double-stage water rocket, the best flight performance can be reached. Compared with the single-stage water rocket, the vertical flight height of the double-stage water rocket is significantly higher than that of the single-stage water rocket.
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Kroninger, Christopher M. "Characteristics of a rotor optimized for hover and forward flight." 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideIndex/ETD-2734/index.html.
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尤皓正. "Characteristics Measurement on Timers for Time-of-flight Laser Rangefinding." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/06077295462212837451.
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Kornienko, Andrei [Verfasser]. "System identification approach for determining flight dynamical characteristics of an airship from flight data / vorgelegt von Andrei Kornienko." 2006. http://d-nb.info/982567677/34.
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Tang, Jhen-Han, and 唐振翰. "Aerodynamic Characteristics of Ground Effect in Flapping Flight of Small Birds." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/81350659928228524193.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
100
An investigation with computational fluid dynamics of the ground effect on a small bird revealed quantitatively the obstruction of the vortex expansion resulting from the presence of the ground at varied distance. Preceding authors focused mainly on the simulation of static bird’s wings, generally neglecting the bird’s body and maneuverable wings; we discuss specifically the distinction of the aerodynamic effect between cases with and without the presence of the bird’s body. The results of static simulation show that, considering only two wings, for a distance between the wing model and the ground smaller than a semi-span, the smaller is the ground clearance, the more significant is the ground effect. At clearance 0.37 times a semi-span, the drag is decreased 12%. The ground effect for an intact bird model composed of both wings and body is less effective than that for a simplified model with body omitted, because a suction was observed on the lower surface of the intact bird’s trunk at clearance 0.37 times a semi-span; for this reason the intact bird model benefits less from the ground effect than the model with body excluded, but increased lift and decreased drag remain observable. In our research we treat the dynamic simulation with maneuverable wings coupling of the flapping, folding, and twisting motion. The results of dynamic simulation show that: There is almost no lift generation in upstroke process; lift is generated in down stroke process. We unexpectedly found that in the model with flapping wings the ram effect dominate the fluid field rather than the wingtip vortex. It is because that the acceleration of the fluid caused by flapping is much bigger than the wingtip vortex does, resulting the effect of the obstruction of the vortex to become weaker. We also found at β = 1.026 the average of lift is increased 47%, and the drag is decreased 20%. The present study provides an insight into experimental and computational research dealing with ground effect of a flapping bird and also reveals the importance of the presence of bird’s body in computational or experimental models.
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CHONG, MING-HAN, and 鍾明翰. "Study on Aerodynamic Characteristics of Coaxial Rotor Vehicle in Forward Flight." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/kz7tcc.
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碩士逢甲大學
航太與系統工程學系
105
In this study, coaxial rotor vehicles with rotor-fuselage combination are simulated numerically to study the aerodynamic characteristics under various operating conditions during the forward flight. The upper and lower rotor each consists of three blades. Two kinds of rotor blade, NACA 0012 (symmetrical wing) and Viper-X (asymmetric wing), are considered. For the latter, in addition, the rotor blade tips with sweepback angles of 20, 35 and 40 deg are taken into accout. The numercial simulations are performed using the commercial package ANSYS/Fluent with mixed model of rotating frame of reference, and combination of structural and nonstructural grid system. The fluid flow is governed by Reynolds-averaged Navier-Stokes equations and the turbulence characteristics are simulated by the SST k-ω model. At the beginning of the study, the downwash speeds at various conditions are compared first, and then the results of lift, torque and forward thrust at conditions of hovering and forward flight, and symmetrical and asymmetric rotors are explored. The influence of the blade tip sweepback on the aerodynamic force is also analyzed. From the results under various operating conditions, it can be summarized that the coaxial rotor of Viper-X blade with tip sweep of 35 deg shows relatively better aerodynamic performance.
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Yang, Shiou Shiuan, and 楊修炫. "Examination of Stability Characteristics and Flight Quality for Transport Aircraft in Severe Atmospheric Turbulence." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/86498245276075921774.
Full textAbstract:
碩士中華科技大學
飛機系統工程研究所
101
Atmospheric turbulence is the leading cause of serious personal injuries in non-fatal accidents of commercial aircraft. One main type of motion that causes flight injuries in atmospheric turbulence is the sudden plunging motion with the abrupt change in altitude. The main objective of the present study is to examine the stability characteristics and flying quality for A300B4-600R and A330-200 transports in cruising and descending phases encountering severe atmospheric turbulence, respectively. In the present study, a numerical modeling method based on Fuzzy-logic Modeling (FLM) technique is presented to estimate the aerodynamic models for these two twin-jet transports by using flight data . Two models are used to analyze stability and flight simulations. The longitudinal and lateral-directional motion modes are analyzed through digital flight simulation based on decoupled and 6-DOF dynamic equations of motion. The fuzzy-logic aerodynamic models are utilized to estimate the nonlinear unsteady aerodynamics while performing numerical integration of flight dynamic equations. The eigenvalues of all motion modes are obtained during time integration. The results are analyzed to provide the mitigation concepts and promote the understanding of aerodynamic responses of the commercial transport aircraft in severe atmospheric turbulence.
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Pradeep, M. "Experimental Study Of Plasma Actuator Characteristics And Optimization Of Configuration." Thesis, 2011. http://etd.iisc.ernet.in/handle/2005/2081.
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Plasma actuators are devices which function by creating a discharge in air at atmospheric conditions. These devices have been demonstrated to effectively delay flow separation and enhance the lift- drag characteristics of wing sections. They have also been shown to have potential
applications in controlling dynamic stall, flow separation control over turbine blades, flow vectoring, boundary layer manipulation and bluff body flow control.
This study examines the characteristics of the plasma actuator, its working and the optimization of its configuration for its use as a lift enhancing device. A single actuator connected to a high-voltage, high-frequency power supply was studied in quiescent conditions. It was demonstrated by means of flow visualization experiments and hot-wire anemometry that the plasma actuator functions by inducing a flow, thus behaving as a source of momentum flux in any system that it is introduced into. Further, it was inferred that the flow induced is a wall jet and that the magnitude of the velocity achieved is maximum within a few millimeters of the surface of the actuator. A parametric investigation of the actuator was conducted next. The variation of the peak velocity induced in quiescent conditions with the variation of configuration parameters was studied by means of photographic studies and hot-wire anemometry. These experiments
indicated that there is a strong correlation between the visible extent of the plasma along the direction of the induced _ow (plasma width) and the peak velocity achieved. The peak velocity achieved is found to increase with the increase in the plasma width as long as the discharge
created is in the uniform glow discharge regime. The development of localized high intensity streamers, which destroy the uniformity of the plasma, lead to a loss in the peak velocity.
Hot-wire tests indicated that the peak velocity increases with a decrease in the spanwise overlap of the electrodes, with the other parameters kept constant. Also, in the uniform glow discharge regime, the velocity increases with the increase in the thickness of the dielectric placed between the two electrodes. After a particular optimum thickness, further increase of the thickness leads to formation of streamers. The velocity increased with a decrease in streamwise overlap, with the maximum being reached for a overlap of approximately 2mm, after which it remained a constant. It was observed that the absence of overlap leads to a loss of uniformity of the discharge created. The velocity was found to be independent of the variations in the electrode widths. Particle Image Velocimetry (PIV) was conducted to study the characteristics of the jet produced. It was observed that when the actuator is switched on, a low pressure region is created near the
surface of the actuator, vertically above it, leading to a flow towards this region from above the actuator. Furthermore, a vortex is shed, which is convected downstream, after which a wall jet is established close to the dielectric surface.
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Chang, Ting Ju, and 張婷茹. "The Study on Job Characteristics and Service Attitudes for Job Satisfaction Influence of Flight Attendants – the Airlines Review as a Moderator." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/75357907261938220502.
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碩士輔仁大學
餐旅管理學系碩士班
97
Airline review played an important role on affecting Airline Company’s brand image and reputation. As a result, in order to make a good impression to passengers, airline companies should hold positive attitude when audited by airline reviews. In this research, it focuses on studying flight attendant’s understanding towards airline review and based on the result to conclude flight attendant’s attitude towards review. Literature review aims to flight attendant’s job characteristics, service quality, service attitude, job satisfaction, audit items and the result of airline review. In this research it studies how job characteristics affect flight attendant’s job satisfaction and how flight attendant perceive his or her working capability and attitude and based on the result to analyze the relationship between job satisfaction and service attitude. Questionnaire Interview was chosen to gather information that represents flight attendant’s attitude and perception towards airline review. Also, analyzing how the review affects airline companies. Based on the result, author suggests some managerial strategies for airline companies when reacting to airline review in the future. 600 Questionnaires were distributed to flight attendants in China Airlines who were chosen at random. 556 copies were recycled which include 14 invalid questionnaires and 30 unanswered, the response rate was 92%. After statistic analysis, the following conclusions were generated:Flight attendant’s job characteristics were affected by job satisfaction, when the perception of flight attendant is higher, job satisfaction is better. Among those job characteristics, feedback is the key factor that affects job satisfaction. When the job is highly related to interactions between passenger and flight attendant, it affects job satisfaction significantly as well. The higher the perception of flight attendant towards his or her service attitude, the better job satisfaction that he or she can enjoys. Regarding service attitudes, assurance and caring play key factors when influencing job satisfaction. When flight attendant posses assured and caring attitude towards his or her job, normally, he or she has higher job satisfaction than others. The interaction between job characteristics and airline review is not significant enough to affect job satisfaction; however, it reaches significant level to affect skill identity, autonomy and job importance. The interaction of assurance and feedback is significant which cause moderation effect in the test. Skill variety, dealing with others and feedback are not significant in the test, these three factors cause no moderation effect in the test so as the interaction of tangible and assurance and empathy. According to the differentiation analysis, it shows no significance in answering the call bell, problem solving ability, enthusiasm of staff, friendliness of staff and courtesy of staff, which represents that those check points, did not affect flight attendant’s job satisfaction. We use Importance-performance Analysis as methodology to find out items that needs to be improved are as followed: answering the call bell, problem solving ability, willing to serve, staff grooming and presentation. These six factors fall in high importance but low performance quadrant which needs more attention from cabin crew department. Food and beverage service efficiency, applying safety procedure, friendiness of staff, courtesy of staff service and consistency of Quality among staff are items that need to to be sustained. In the result of this reasearch, it shows that flight attendants tend to have highier expectation and anticipation towards those items which can be the listed as a strength when airline company was evaluated by audit institute. Secondary priority items are staff language skills, Enthusiasm of staff, total cabin presence, welcome passengers, and discipline among staff. Performance regarding these items is below the average and the cabin crew department should spend more time on altering the service strategy. Assisting passengers during boarding falls on the quadrant that represents less importance but high performance which means it is over-qualified and fulfill the standard set by the airline audit institute.
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Hinson, Daniel Keith. "Assement of the flight test methodology and separation characteristics of the AGM-154A joint standoff weapon (JSOW) on the F/A-18C/D Hornet." 2006. http://etd.utk.edu/2006/HinsonDaniel.pdf.
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Agenbag, Daniel Sarel. "Longitudinal handling characteristics of a tailless gull-wing aircraft." Diss., 2008. http://hdl.handle.net/2263/28011.
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A handling quality investigation was performed on the swept gull-wing configuration. The swept gull-wing configuration is tailless and has a wing with a transition in the sweep and dihedral angle. An example of this type of aircraft is the Exulans. This aircraft is currently under development at the University of Pretoria. The handling quality study was focussed on pitch axis dynamics. The Exulans is a research testbed that will be used to investigate the swept gull-wing configuration and its special controls by means of full-scale flight testing. Variable wing sweep, twisting elevons and winglets will be investigated as means of control. These control devices are configured in such a way as to have minimum impact on the performance of the aircraft. The handling qualities of the swept gull-wing configuration have to be acceptable while using these different control strategies. The study was launched to investigate whether a gull-wing configuration aircraft will have satisfactory handling qualities at CG positions associated with the most favourable aerodynamic performance. There is an aerodynamic performance gain in designing an aircraft so that the CG falls on the so-called `E-point'. The E-point is the centre of pressure for an elliptical circulation distribution. An elliptical circulation distribution is associated with the highest Oswald efficiency for an aircraft. Time domain simulation techniques and frequency domain analysis techniques were used to analyse the handling qualities of the gull-wing configuration. The C-star criterion was used to analyse handling qualities with time domain simulation data as input. Comparative time domain simulations were performed between the Exulans and other aircraft to compare handling qualities. Eigenvalue analysis was used together with the thumbprint criterion to investigate inherent gull-wing airframe dynamics. The Shomber-Gertsen and Military Specification 8785 criteria were also used for the same purpose. The Neal-Smith method was used to investigate the effect of control authority on handling qualities and the effect of a pilot. The Monnich and Dalldorff criterion was used to evaluate gust handling qualities. An analysis chart by Fremaux and Vairo was used to evaluate the tumbling susceptibility of the gull-wing configuration. The pitch handling quality investigation shows sufficient promise that the swept gull-wing configuration will have acceptable handling qualities with the CG placed at positions associated with optimised aerodynamic performance. Analysis showed that the swept gull-wing configuration is potentially prone to tumbling. With low static margins, the configuration should exhibit improved handling qualities in gusty conditions when compared to existing tailless aircraft. It is recommended that a lateral handling quality study be performed before full scale flight testing commences on the Exulans. In addition, the possibility of wingtip stall must be investigated for the case of the swept gull-wing configuration.Dissertation (MEng)--University of Pretoria, 2008.
Mechanical and Aeronautical Engineering
unrestricted
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Berglund, Jacob, and Martin Ericsson. "Key Characteristics as a Practice toAchieve Robust Design : A case study in the aerospace industry." Thesis, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-49690.
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Continuous technological development and increasing efficiency demands are driving products toward becoming more and more complex. For the aerospace industry - where the requirements for performance, safety and low environmental impact already are substantial - this means that more extensive quality assurance measures must be taken to ensure the fulfillment of the requirements of each individual component.However, to avoid that the work with quality improvement become too extensive and increase the product cost to unbearable levels it is necessary to have methods to prioritize and focus improvement efforts on the product features that matters most for fulfilling customer requirements. Therefore, the concept of Key Characteristics is used today, both in the aerospace and other industries; a term for those characteristics that have a significant impact on requirement compliance and whose outcomes at the same time are expected to vary considerably in manufacturing.The concept itself is similar among those who use it but the purpose of and methodology for identifying and managing Key Characteristics vary, even within the same industry. This thesis is therefore aimed to create a view of which factors that characterize an effective and efficient way for companies in the aerospace industry to work with Key Characteristics. The thesis involves a case study to create a framework for how companies within this industry work with Key Characteristics, a literature review to see which approaches are advocated by previous research and two benchmark studies to see examples of how Key Characteristics are used and handled in practice in industry.The results show that the work of Key Characteristics should meet three main criteria in order to be effective and efficient: • it must be clearly focused on the characteristics that have critical impact on customer requirements and at the same time considerable variation in production, • it should be initiated early in the product development process and then performed iteratively during the process of continuously reducing variation problems in manufacturing, and • it should identify Key Characteristics using both qualitative and quantitative tools to best capture all different kinds of requirements on the product.Finally a practical example is given of how the work with Key Characteristics should look like at GKN Sweden AB, the case study company in the aerospace industry, to effectively minimize the costs associated with production variation, and yet satisfy all customer requirements.Validerat; 20140811 (global_studentproject_submitter)
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Keng-ChongFong and 馮景聰. "The Applications of Neural Network on Characteristic Analysis of Flight Safety." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/38417030367420191641.
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碩士國立成功大學
民航研究所
101
The goal of this study is to investigate the possibility of establishing the flight characteristic using the technique of data compression with neural network, in order to improve flight risk assessments which greatly depend on experts’ assessments or FOQA system. This study defined four flight characteristics, and the compression efficiencies of those characteristics have a correlation coefficient (CC) within the range 0.85~1 and an average index of agreement (IOA) within the range 85%~99%. Those show that some flight parameters are reasonable to become flight characteristics. With the calculation of the characteristic deviation, it can provide the deviation of accident flights from the normal standard. The results of this study show that flight characteristics are acceptable as quantitative measures in abnormal flight operations. According to any two flight characteristics’ correlation coefficient and inner product, all of them have different degrees correlated to each other.
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Wang, Li-Chuan, and 王麗娟. "An Empirical Study on the Job Characteristic, Job Stress among Flight Attendants." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/33195258143891708953.
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碩士國立中央大學
人力資源管理研究所碩士在職專班
91
There are many studies on the job stress, the impact resulting from job stress and change of employee’s behavior. Excessive stress is mentally harmful to the employee, which will directly affect the efficiency of the organization. According to the surveys done both domestically and abroad in the past few years, job seekers, especially young people, placed flight attendants with high priority in their career management. Flight attendants work on roster duty to provide comfortable and safe services in the cabin for the passengers. The purpose of the study is to have a clear picture on the relations of the characteristics of the job of flight attendant, job stress and the impact on occupational health and job satisfaction. This is a study on the flight attendants of a private airline. The Chinese OSI-2 system is applied to help working out the report. There were 154 survey forms in total being distributed to the flight attendants. All the forms were returned with 137 successful responses. It represents an 88.96% available data. Basing on the statistical analysis, we have the following findings: 1.Three most significant factors leading to the cause of stress are “recognition”, “personal responsibility” and “relationship”. 2.Inadequate performance is the main concern on occupational stress among flight attendants. 3.“Relationship”, “managerial role” and “recognition” will have a big impact on mental status of flight attendants. 4.Physical status is tremendously affected by “personal responsibility”. 5.“Organizational climate” plays a leading role in the area of job satisfaction. To assist the flight attendants to effectively minimize and manage occupational stress, the company is suggested to strategically improve working environment, management style and enhance the capability of flight attendants in this regard.
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(8054564), Katherine Elisabeth Wehde. "THE DEVELOPMENT OF MASS SPECTROMETRIC METHODS FOR THE DETERMINATION OF THE CHEMICAL COMPOSITION OF COMPLEX MIXTURES RELEVANT TO THE ENERGY SECTOR AND THE DEVELOPMENT OF A NEW DEVICE FOR CHEMICALLY ENHANCED OIL RECOVERY FORMULATION EVALUATION." Thesis, 2019.
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This dissertation focused on the development of mass spectrometric methodologies, separation techniques, and engineered devices for the optimal analysis of complex mixtures relevant to the energy sector, such as alternative fuels, petroleum-based fuels, crude oils, and processed base oils. Mass spectrometry (MS) has been widely recognized as a powerful tool for the analysis of complex mixtures. In complex energy samples, such as petroleum-based fuels, alternative fuels, and oils, high-resolution MS alone may not be sufficient to elucidate chemical composition information. Separation before MS analysis is often necessary for such highly complex energy samples. For volatile samples, in-line two-dimensional gas chromatography (GC×GC) can be used to separate complex mixtures prior to ionization. This technique allows for a more accurate determination of the compounds in a mixture, by simplifying the mixture into its components prior to ionization, separation based on mass-to-charge ratio (m/z), and detection. A GC×GC coupled to a high-resolution time-of-flight MS was utilized in this research to determine the chemical composition of alternative aviation fuels, a petroleum-based aviation fuel, and alternative aviation fuel candidates and blending components as well as processed base oils.
Additionally, as the cutting edge of science and technology evolve, methods and equipment must be updated and adapted for new samples or new sector demands. One such case, explored in this dissertation, was the validation of an updated standardized method, ASTM D2425 2019. This updated standardized method was investigated for a new instrument and new sample type for a quadrupole MS to analyze a renewable aviation fuel. Lastly, the development and evaluation of a miniaturized coreflood device for analyzing candidate chemically enhanced oil recovery (cEOR) formulations of brine, surfactant(s), and polymer(s) was conducted. The miniaturized device was used in the evaluation of two different cEOR formulations to determine if the components of the recovered oil changed.
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TZU-JUNG, CHEN, and 陳姿蓉. "The Relationship between Cognition of Job Characteristic and Self-Actualization for The Flight Attendants." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/42038814618595307571.
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碩士中國文化大學
觀光事業研究所
97
Being a flight attendant is a dream job for many people who just graduated from school. It is not only a job with high salary and well company benefits, but also it that can extend our vision of the world. However, this occupation actually contains many kinds of pressure and risk of disease. And in recent years, the research of flight attendants on self-actualization is still not discussed in aviation transportation service in Taiwan. It is an important issue to discuss how the degree of flight attendant’s self-actualization would affect their work performance. As a result, the objective of this study is to understand the relationship between the cognition of job characteristics and the cognition of occupation hazard for flight attendants and to understand the relationship between the cognition of occupation hazard and self-actualization for flight attendants and to understand the relationship between the cognition of job characteristics and self-actualization for flight attendants. The survey was conducted from April to May 2009. A total of 358 questionnaires were completed, of which 348 were valid. The result showed the cognition of occupation hazard has a negative relationship to self-actualization and the cognition of job characteristics has a positive relationship to self-actualization. The finding not only pointed relationships between the cognition of job characteristics, the cognition of occupation hazard and self-actualization among flight attendants, but give airlines some suggestions: design a new indicator about the performance appraisal and develop a new training program for employees (e.g., aviation safety or prevention of the occupation hazard etc.) to promote flight attendants’ self-actualization.
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Kaur, Sukhdeep. "An empirical study of SD signal delay versus temperature in a plenum grade coaxial cable." Thesis, 2010. http://hdl.handle.net/2152/ETD-UT-2010-12-2534.
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A high resolution speedy delivery time domain reflectometer (SD/TDR) has been developed in the Electrical Engineering department at The University of Texas at Austin. The SD/TDR uses a novel non-sinusoidal signal that does not undergo dispersion during transmission in a lossy media. SD/TDR is used to estimate the length and detect the location of faults in the transmission lines. Time of flight (TOF) is one of the critical parameters of SD/TDR and a function of several temperature dependent factors. Given the TOF and length of a transmission line, signal delay can be computed. This research presents an empirical study of the effect of temperature on the TOF in a plenum grade coaxial cable for temperatures ranging from -3 °C to 60 °C. We also study the effect of temperature on characteristic impedance of the coaxial cable. Finally, a SD double exponential waveform is used to estimate TOF for calibrated short and open terminations.text
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ZHUANG, ZHOU-RUI, and 莊周瑞. "Genetics and growth characteristics of maize hybrid combinations from flint and dent kernel forms." Thesis, 1989. http://ndltd.ncl.edu.tw/handle/86746217888029350571.
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