Dissertations / Theses on the topic 'Flying wing'
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1
Farrell, Joseph H. "DYNAMICALLY SCALED OBLIQUE FLYING WING." Thesis, The University of Arizona, 2009. http://hdl.handle.net/10150/192337.
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Huang, Haidong. "Optimal design of a flying-wing aircraft inner wing structure configuration." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7439.
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Flying-wing aircraft are considered to have great advantages and potentials in
aerodynamic performance and weight saving. However, they also have many
challenges in design. One of the biggest challenges is the structural design of
the inner wing (fuselage). Unlike the conventional fuselage of a tube
configuration, the flying-wing aircraft inner wing cross section is limited to a
noncircular shape, which is not structurally efficient to resist the internal
pressure load. In order to solve this problem, a number of configurations have
been proposed by other designers such as Multi Bubble Fuselage (MBF),
Vaulted Ribbed Shell (VLRS), Flat Ribbed Shell (FRS), Vaulted Shell
Honeycomb Core (VLHC), Flat Sandwich Shell Honeycomb Core (FLHC), Y
Braced Box Fuselage and the modified fuselage designed with Y brace
replaced by vaulted shell configurations. However all these configurations still
inevitably have structural weight penalty compared with optimal tube fuselage
layout. This current study intends to focus on finding an optimal configuration
with minimum structural weight penalty for a flying-wing concept in a preliminary
design stage.
A new possible inner wing configuration, in terms of aerodynamic shape and
structural layout, was proposed by the author, and it might be referred as
‘Wave-Section Configuration’. The methodologies of how to obtain a structurally
efficient curvature of the shape, as well as how to conduct the initial sizing were
incorporated.
A theoretical analysis of load transmission indicated that the Wave-Section
Configuration is feasible, and this was further proved as being practical by FE
analysis. Moreover, initial FE analysis and comparison of the Wave-Section
Configuration with two other typical configurations, Multi Bubble Fuselage and
Conventional Wing, suggested that the Wave-Section Configuration is an
optimal design in terms of weight saving. However, due to limitations of the
author’s research area, influences on aerodynamic performances have not yet
been taken into account.
3
Saeed, Tariq Issam. "Conceptual design for a laminar-flying-wing aircraft." Thesis, University of Cambridge, 2012. https://www.repository.cam.ac.uk/handle/1810/243926.
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The laminar-flying-wing aircraft appears to be an attractive long-term prospect for reducing the environmental impact of commercial aviation. In assessing its potential, a relatively straightforward initial step is the conceptual design of a version with restricted sweep angle. Such a design is the topic of this thesis. In addition to boundary layer laminarisation (utilising distributed suction) and limited sweep, a standing-height passenger cabin and subcritical aerofoil flow are imposed as requirements. Subject to these constraints, this research aims to: provide insight into the parameters affecting practical laminar-flow-control suction power requirements; identify a viable basic design specification; and, on the basis of this, an assessment of the fuel efficiency through a detailed conceptual design study. It is shown that there is a minimum power requirement independent of the suction system design, associated with the stagnation pressure loss in the boundary layer. This requirement increases with aerofoil section thickness, but depends only weakly on Mach number and (for a thick, lightly-loaded laminar flying wing) lift coefficient. Deviation from the optimal suction distribution, due to a practical chamber-based architecture, is found to have very little effect on the overall suction coefficient. In the spanwise direction, through suitable choice of chamber depth, the pressure drop due to frictional and inertial effects may be rendered negligible. Finally, it is found that the pressure drop from the aerofoil surface to the pump collector ducts determines the power penalty; suggesting there is little benefit in trying to maintain an optimal suction distribution through increased subsurface-chamber complexity. For representative parameter values, the minimum power associated with boundary-layer losses alone contributes some 80% - 90% of the total power requirement. To identify the viable basic design specification, a high-level exploration of the laminar-flying-wing design space is performed, with an emphasis above all on aerodynamic efficiency. The characteristics of the design are assessed as a function of three parameters: thickness-to-chord ratio, wingspan, and unit Reynolds number. A feasible specification, with 20% thickness-to-chord, 80 m span and a unit Reynolds number of 8 x 10[superscript 6] m[superscript -1], is identified; it corresponds to a 187 tonne aircraft which cruises at Mach 0.67 and altitude 22,500 ft, with lift coefficient 0.14. The benefit of laminarisation is manifested in a high lift-to-drag ratio, but the wing loading is low, and the structural efficiency and gust response are thus likely to be relatively poor. On the basis of this specification, a detailed conceptual design is undertaken. A 220-passenger laminar-flying-wing concept, propelled by three turboprop engines, with a cruise range of 9000 km is developed. The estimated fuel burn is 13.9 g/pax.km. For comparison, a conventional aircraft, propelled by four turboprop engines, with a high-mounted, unswept, wing is designed for the same mission specification and propulsion characteristics, and is shown to have a fuel burn of 15.0 g/pax.km. Despite significant aerodynamic efficiency gains, the fuel burn of the laminar flying wing is only marginally better as it suffers from a poor cruise engine efficiency, due to extreme differences between takeoff and cruising requirements, and is much heavier. The laminar flying wing proposed in this thesis falls short of the performance improvements expected of the concept, and is not worth the development effort. It is therefore proposed that research efforts either be focussed on improving the engine efficiency, or switching to a low aspect ratio, high sweep, design configuration.
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Levis, Errikos. "Design synthesis of advanced technology, flying wing seaplanes." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9943.
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Over the past decades there has been increasing pressure for ever more efficient and environmentally friendly aircraft to be designed. The use of waterborne aircraft could be a means of satisfying those requirements in the future. The aim of the PhD research program presented in this thesis was to develop the methodologies necessary for the preliminary design of large passenger seaplanes and evaluate the performance of such an aircraft compared to the current state of the art. The major technological and operational constraints in designing large waterborne aircraft were identified through an extensive feasibility study. A number of subject areas necessitating further investigation were also identified. To ensure that waterborne takeoff distance requirements are met, a novel initial sizing methodology was generated, relating the aircraft's thrust and lifting characteristics to the takeoff Balanced Field Length. To allow the design of a broad family of aircraft based on a predefined baseline configuration, the seaplane geometry was fully parameterized. The aerodynamic properties of the entire aircraft were determined using a vortex-lattice potential flow solver, written specifically for the configuration being investigated, combined with other commonly used empirical methods. Novel methodologies for estimating the hydrodynamic characteristics of a broad range of parametric hulls were developed using the wealth of experimental hydrodynamic test data available. These methods can be used not only to predict the resistance and trim characteristics of a seaplane throughout the entire takeoff and landing manoeuvre but also give an initial estimate of the attitudes where hydrodynamic instabilities may be encountered. The airborne and waterborne performance characteristics of each resulting aircraft design were estimated using the aforementioned methods. The resulting design synthesis has been integrated into a single algorithm, written in FORTRAN, intended to allow the easy and prompt analysis of any parametric variant of the baseline configuration.
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Aguirre, John. "Study of 3-Dimensional Co-Flow Jet Airplane and High-Rise Building Flow Using CFD Simulation." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_theses/181.
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The purpose of this thesis is to design and study an aircraft which implements the Co-Flow Jet (CFJ) airfoil concept, as well as to study the CAARC standard highrise building. The design concept is verified mainly by the use of a Computational Fluid Dynamics (CFD) package. A thorough methodology for geometry and mesh generation is developed, and subsequently applied to the two cases. The first case studied is that of the CFJ Airplane (CFJA). It consists of a threedimensional, highly blended, ying wing geometry implementing the Co-Flow Jet airfoil concept. Though a thorough comparison to a baseline geometry, it is shown that usage of the CFJ airfoil cross-section greatly improves aircraft performance by increasing lift, reducing drag, and providing a source of thrust over the operational range of angles of attack. A steady state CFD simulation is used for this case, as the air ow around an airfoil cross-section is inherently steady for attached ows. CFD results are used to support the Engineless Aircraft" concept, where the CFJ airfoil is used as the sole form of propulsion. The second case studied consists of a rectangular high-rise building undergoing a wind condition with Mach number of 0:1 and a Reynolds number of 160000. Due to the non-streamlined geometry of the building cross-section, aerodynamic instabilities due to uid separation are present, and therefore an unsteady CFD analysis is necessary to fully resolve all of the ow phenomena. Preliminary steady state results are presented, and a plan is laid down for the future study of this highly complex case. Results are presented for a variety of angles of attack in the case of the CFJA, and for the main ow direction in the case of the CAARC building. Results are compared with baseline geometry in the case of the CFJ Airplane. The CFJ Airplane case is simulated using a 3rd order steady state scheme, which is sufficient to achieve valid results for the ow regime. The CAARC building, which has inherent ow separation, requires the use of high order schemes.
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Zhu, Yan. "Longitudinal control laws design for a flying wing aircraft." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7423.
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This research is concerned with the flight dynamic, pitch flight control and flying
qualities assessment for the reference BWB aircraft. It aims to develop the
longitudinal control laws which could satisfy the flying and handing qualities
over the whole flight envelope with added consideration of centre of gravity (CG)
variation.
In order to achieve this goal, both the longitudinal stability augmentation system
(SAS) and autopilot control laws are studied in this thesis. Using the pole
placement method, two sets of local Linear-Time-Invariant (LTI) SAS controllers
are designed from the viewpoints of flying and handing qualities assessment
and wind disturbance checking. The global gain schedule is developed with the
scheduling variable of dynamic pressure to transfer gains smoothly between
these two trim points. In addition, the poles movement of short period mode with
the varying CG position are analysed, and some approaches of control system
design to address the problem of reduced stability induced by CG variation are
discussed as well. To achieve the command control for the aircraft, outer loop
autopilot both pitch attitude hold and altitude hold are implemented by using the
root locus method.
By the existing criteria in MIL-F-8785C specifications being employed to assess
the augmented aircraft response, the SAS linear controller with automatic
changing gains effectively improve the stability characteristic for the reference
BWB aircraft over the whole envelope. Hence, the augmented aircraft equals to
a good characteristic controlled object for the outer loop or command path
design, which guarantee the satisfactory performance of command control for
the BWB aircraft.
The flight control law for the longitudinal was completed with the SAS controller
and autopilot design. In particular, the SAS was achieved with Level 1 flying and
handing qualities, meanwhile the autopilot system was applied to obtain a
satisfactory pitch attitude and altitude tracking performance.
7
Iglesias, Sergio. "Optimum Spanloads Incorporating Wing Structural Considerations And Formation Flying." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35718.
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The classic minimum induced drag spanload is not necessarily the best choice for an aircraft. For a single aircraft configuration, variations from the elliptic, minimum drag optimum load distribution can produce wing weight savings that result in airplane performance benefits. For a group of aircraft flying in formation, non-elliptic lift distributions can give high induced drag reductions both for the formation and for each airplane.
For single aircraft, a discrete vortex method which performs the calculations in the Trefftz plane has been used to calculate optimum spanloads for non-coplanar multi-surface configurations. The method includes constraints for lift coefficient, pitching moment coefficient and wing root bending moment. This wing structural constraint has been introduced such that wing geometry is not changed but the modified load distributions can be related to wing weight. Changes in wing induced drag and weight were converted to aircraft total gross weight and fuel weight benefits, so that optimum spanloads that give maximum take-off gross weight reductions can be found. Results show that a reduction in root bending moment from a lift distribution that gives minimum induced drag leads to more triangular spanloads, where the loads are shifted towards the root, reducing wing weight and increasing induced drag. A slight reduction in root bending moment is always beneficial, since the initial increase in induced drag is very small compared to the wing weight decrease. Total weight benefits were studied for a Boeing 777-200IGW type configuration, obtaining take-off gross weight improvements of about 1% for maximum range missions. When performing economical, reduced-range missions, improvements can almost double. A long range, more aerodynamically driven aircraft like the Boeing 777-200IGW will experience lower benefits as a result of increasing drag. Short to medium range aircraft will profit the most from more triangular lift distributions.
Formation flight configurations can also result in large induced drag reductions for load distributions that deviate from the elliptical one. Optimum spanloads for a group of aircraft flying in an arrow formation were studied using the same discrete vortex method, now under constraints in lift, pitching moment and rolling moment coefficients. It has been shown that large general improvements in induced drag can be obtained when the spanwise and vertical distances between aircraft are small. In certain cases, using our potential flow vortex model, this results in negative (thrust) induced drag on some airplanes in the configuration. The optimum load distributions necessary to achieve these benefits may, however, correspond to a geometry that will produce impractical lift distributions if the aircraft are flying alone. Optimum separation among airplanes in this type of formation is determined by such diverse factors as the ability to generate the required optimum load distributions or the need for collision avoidance.
Master of Science
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Geyman, Matthew Kenneth. "Wing/Wall Aerodynamic Interactions in Free Flying, Maneuvering MAVs." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1335113432.
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Cheng, Yun. "Preliminary fuselage structural configuration of a flying-wing type airline." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7419.
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The flying-wing is a type of configuration which is a tailless airplane accommodating all of its parts within the outline of a single airfoil. Theoretically, it has the most aerodynamic efficiency. The fuel consumption can be more efficient than the existed conventional airliner. It seems that this configuration can achieve the above mentioned requirements.
According to these outstanding advantages, many aircraft companies did a great deal of projects on the flying-wing concept. However, the application was only for sport and military use; for airliner, none of them entered production.
FW-11 is a flying-wing configuration airliner which is a design cooperation between Cranfield University and Aviation Industry Corporation of China (AVIC). Aiming the spatial economic and environmental needs, this 200-seat airliner would attract attention from airline companies for cost saving and environmental protection.
Before start, this program is designated for a new generation commercial aircraft to compete with the existing same capability airliner, such as Airbus A320 and Boeing 767. As the first team of this program, the aim is to finish the conceptual design and prepare the relevant document for next two teams that will perform preliminary and detail design.
As a member of FW-11 program and as part of the GDP, the author has been through the four conceptual design stages: engine manufacturers, aircraft family issues, structure design and the establishment of 3-D CAD model.
The aim of IRP study is to focus on the initial fuselage design.
10
Tonti, Jacopo. "Development of a Flight Dynamics Modelof a Flying Wing Configuration." Thesis, KTH, Aerodynamik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-159873.
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The subject of UCAV design is an important topic nowadays and many countries have their own programmes. An international group, under the initiative of the NATO RTO AVT-201 Task group, titled “Extended Assessment of Reliable Stability & Control Prediction Methods for NATO Air Vehicles”, is currently performing intensive analysis on a generic UCAV configuration, named SACCON. In this thesis the stability and control characteristics of the SACCON are investigated, with the purpose of carrying out a comprehensive assessment of the flying qualities of the design. The study included the generation of the complete aerodynamic database of the aircraft, on the basis of the experimental data measured during TN2514 and TN2540 campaigns at DNW-NWB low speed wind tunnel. Moreover, system identification techniques were adopted for the extraction of dynamic derivatives from the time histories of forced oscillation runs. The trim of the aircraft was evaluated across the points of a reasonable test envelope, so as to define a set of plausible operative conditions, representing the reference conditions for subsequent linearization of the dynamic model. The study provided a thorough description of the stability and control characteristics and flying qualities of the unaugmented SACCON, laying the groundwork for future improvement and validation of the configuration in the next design stages.
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Ikeda, Toshihiro, and toshi ikeda@gmail com. "Aerodynamic Analysis of a Blended-Wing-Body Aircraft Configuration." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070122.163030.
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In recent years unconventional aircraft configurations, such as Blended-Wing-Body (BWB) aircraft, are being investigated and researched with the aim to develop more efficient aircraft configurations, in particular for very large transport aircraft that are more efficient and environmentally-friendly. The BWB configuration designates an alternative aircraft configuration where the wing and fuselage are integrated which results essentially in a hybrid flying wing shape. The first example of a BWB design was researched at the Loughead Company in the United States of America in 1917. The Junkers G. 38, the largest land plane in the world at the time, was produced in 1929 for Luft Hansa (present day; Lufthansa). Since 1939 Northrop Aircraft Inc. (USA), currently Northrop Grumman Corporation and the Horten brothers (Germany) investigated and developed BWB aircraft for military purposes. At present, the major aircraft industries and several universities has been researching the BWB concept aircraft for civil and military activities, although the BWB design concept has not been adapted for civil transport yet. The B-2 Spirit, (produced by the Northrop Corporation) has been used in military service since the late 1980s. The BWB design seems to show greater potential for very large passenger transport aircraft. A NASA BWB research team found an 800 passenger BWB concept consumed 27 percent less fuel per passenger per flight operation than an equivalent conventional configuration (Leiebeck 2005). The purpose of this research is to assess the aerodynamic efficiency of a BWB aircraft with respect to a conventional configuration, and to identify design issues that determine the effectiveness of BWB performance as a function of aircraft payload capacity. The approach was undertaken to develop a new conceptual design of a BWB aircraft using Computational Aided Design (CAD) tools and Computational Fluid Dynamics (CFD) software. An existing high-capacity aircraft, the Airbus A380 Contents RMIT University, Australia was modelled, and its aerodynamic characteristics assessed using CFD to enable comparison with the BWB design. The BWB design had to be compatible with airports that took conventional aircraft, meaning a wingspan of not more than 80 meters for what the International Civil Aviation Organisation (ICAO) regulation calls class 7 airports (Amano 2001). From the literature review, five contentions were addressed; i. Is a BWB aircraft design more aerodynamically efficient than a conventional aircraft configuration? ii. How does the BWB compare overall with a conventional design configuration? iii. What is the trade-off between conventional designs and a BWB arrangement? iv. What mission requirements, such as payload and endurance, will a BWB design concept become attractive for? v. What are the practical issues associated with the BWB design that need to be addressed? In an aircraft multidisciplinary design environment, there are two major branches of engineering science; CFD analysis and structural analysis; which is required to commence producing an aircraft. In this research, conceptual BWB designs and CFD simulations were iterated to evaluate the aerodynamic performance of an optimal BWB design, and a theoretical calculation of structural analysis was done based on the CFD results. The following hypothesis was prompted; A BWB configuration has superior in flight performance due to a higher Lift-to-Drag (L/D) ratio, and could improve upon existing conventional aircraft, in the areas of noise emission, fuel consumption and Direct Operation Cost (DOC) on service. However, a BWB configuration needs to employ a new structural system for passenger safety procedures, such as passenger ingress/egress. The research confirmed that the BWB configuration achieves higher aerodynamic performance with an achievement of the current airport compatibility issue. The beneficial results of the BWB design were that the parasite drag was decreased and the spanwise body as a whole can generate lift. In a BWB design environment, several advanced computational techniques were required to compute a CFD simulation with the CAD model using pre-processing and CFD software.
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Xu, Rongxin. "Optimal design of a composite wing structure for a flying-wing aircraft subject to multi-constraint." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7290.
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This thesis presents a research project and results of design and optimization of a composite wing structure for a large aircraft in flying wing configuration. The design process started from conceptual design and preliminary design, which includes initial sizing and stressing followed by numerical modelling and analysis of the wing structure. The research was then focused on the minimum weight optimization of the /composite wing structure /subject to multiple design /constraints. The modelling, analysis and optimization process has been performed by using the NASTRAN code. The methodology and technique not only make the modelling in high accuracy, but also keep the whole process within one commercial package for practical application.
The example aircraft, called FW-11, is a 250-seat commercial airliner of flying wing configuration designed through our MSc students Group Design Project (GDP) in Cranfield University. Started from conceptual design in the GDP, a high-aspect-ratio and large sweepback angle flying wing configuration has been adopted. During the GDP, the author was responsible for the structural layout design and material selection. Composite material has been chosen as the preferable material for both the inner and outer wing components. Based on the derivation of structural design data in the conceptual phase, the author continued with the preliminary design of the outer wing airframe and then focused on the optimization of the composite wing structure. Cont/d.
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Tsagarakis, Mikis. "Project Solaris - Analysis of airfoil for solar powered flying wing UAV." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-13168.
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This study is part of the second phase of the Solaris project, where the aim is to develop a solar powered Unmanned Aerial Vehicle (UAV). The second phase involves the design and optimization of the aircraft. One of the important focuses in this phase is the determination of the airfoils shape. This report sole objective is to determine which airfoil that is best suited for the aircraft, as well as presenting the airfoils characteristic properties, in comparison to other similarly airfoils.This analysis has been carried out using XFOIL, an airfoil analysis tool developed by the MIT professor Mark Drela. What has been done in this report: Comparison between a number of potential airfoils. Determination of the winner airfoil. Comparison between the winner airfoil and a conventional (non-reflexed trailing edge) airfoil. Calculation of the hinge moments on the winner airfoil for different flap settings. Winner airfoil: The Phoenix (Phönix) turned out to be the best airfoil in the comparison, closely followed by the S5020 and the S5010. Phoenix had the highest value of the parameter sought to optimize, which is endurance (CL 3/2/ CD). Phoenix maximum endurance (CL 3/2/ CD) for five different Reynold numbers: Re Endurance 400.000 85,64 300.000 78,26 200.000 67,74 100.000 49,47 50.000 25,52 Phoenix geometry: Maximum thickness (in percentage of chord): 8,194% Maximum camber (in percentage of chord): 2,774%Den här rapporten är en del i den andra fasen av Solaris-projektet, där målet är att utveckla en solcellsdriven obemannad flygande farkost (Unmanned Aerial Vehicle, UAV). Den andra fasen omfattar konstruktionen och optimeringen av farkosten (flygplanet). En av de viktigaste byggstenarna i den här fasen är fastställandet av vingprofilens form och design, det vill säga valet av vingprofil. Målet med den här rapporten är att helt och hållet bestämma vilken vingprofil som ska användas på flygplanet, samt en presentation av dess karakteristiska egenskaper. Detta har gjorts i jämförelse med andra liknande vingprofiler. Verktyget som använts för denna jämförelse heter XFOIL. Programmet är utvecklat av professor Mark Drela på MIT i USA, och är gjort för analysering av vingprofiler. Det här har gjorts i rapporten: Jämförelse mellan en mängd olika potentiella vingprofiler. En vinnarprofil har valts ut. Jämförelse mellan vinnarprofilen och en vanlig (non-reflexed trailing edge) vingprofil. Beräkning av de moment som krävs för att styra klaffar och roder. Vinnarprofilen: I jämförelsen visade det sig att Phoenix var den bästa vingprofilen, tätt följt av S5020 och S5010. Phoenix hade det högsta och bäst värdet i den eftersökta parametern ”endurance” (CL 3/2/ CD). Phoenix maximum endurance (CL 3/2/ CD) för fem olika Reynoldstal: Re Endurance 400.000 85,64 300.000 78,26 200.000 67,74 100.000 49,47 50.000 25,52 Phoenix geometri: Maximal tjocklek (i procent av kordan): 8,194% Maximal välvning (i procent av kordan): 2,774%
Solaris
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McFarlane, Cormac. "An investigation of flying qualities for fixed wing unmanned aerial vehicles." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508060.
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Fan, Xiaozhou. "Canonical Decomposition of Wing Kinematics for a Straight Flying Insectivorous Bat." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/91469.
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Bats are some of the most agile flyers in nature. Their wings are highly articulated which affords them very fine control over shape and form. This thesis investigates the flight of Hipposideros Pratti. The flight pattern studied is nominally level and straight. Measured wing kinematics are used to describe the wing motion. It is shown that Proper Orthogonal Decomposition (POD) can be used to effectively to filter the measured kinematics to eliminate outliers which usually manifest as low energy higher POD modes, but which can impact the stability of aerodynamic simulations. Through aerodynamic simulations it is established that the first two modes from the POD analysis recover 62% of the lift, and reflect a drag force instead of thrust, whereas the first three modes recover 77% of the thrust and even more lift than the native kinematics. This demonstrates that mode 2, which features a combination of spanwise twisting (pitching) and chordwise cambering, is critical for the generation of lift, and more so for thrust. Based on these inferences, it is concluded that the first 7 modes are sufficient to represent the full native kinematics.
The aerodynamic simulations are conducted using the immersed boundary method on 128 processors. They utilize a grid of 31 million cells and the bat wing is represented by about 50000 surface elements. The movement of the immersed wing surface is defined by piecewise cubic splines that describe the time evolution of each control point on the wing.
The major contribution of this work is the decomposition of the native kinematics into canonical flapping wing physical descriptors comprising of the flapping motion, stroke-plane deviation, pitching motion, chordwise, and spanwise cambering. It is shown that the pitching mode harvests a Leading Edge Vortex (LEV) during the upstroke to produce thrust. It also stabilizes the LEV during downstroke, as a result, larger lift and thrust production is observed. Chordwise cambering mode allows the LEV to glide over and cover a large portion of the wing thus contributing to more lift while the spanwise cambering mode mitigates the intensification of LEV during the upstroke by relative rotation of outer part of the wing ( hand wing ) with respect to the inner part of the wing ( arm wing).
While this thesis concerns itself with near straight-level flight, the proposed decomposition can be applied to any complex flight maneuver and provide a basis for unified comparison not only over different bat flight regimes but also across other flying insects and birds.MS
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Miao, Zhisong. "Aircraft engine performance and integration in a flying wing aircraft conceptual design." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7249.
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The increasing demand of more economical and environmentally friendly aero
engines leads to the proposal of a new concept – geared turbofan. In this thesis,
the characteristics of this kind of engine and relevant considerations of
integration on a flying wing aircraft were studied.
The studies can be divided into four levels: GTF-11 engine modelling and
performance simulation; aircraft performance calculation; nacelle design and
aerodynamic performance evaluation; preliminary engine installation.
Firstly, a geared concept engine model was constructed using TURBOMATCH
software. Based on parametric analysis and SFC target, the main cycle
parameters were selected. Then, the maximum take-off thrust was verified and
corrected from 195.56kN to 212kN to meet the requirements of take-off field
length and second segment climb. Besides, the engine performance at offdesign
points was simulated for aircraft performance calculation.
Secondly, an aircraft performance model was developed and the performance
of FW-11 was calculated on the basis of GTF-11 simulation results. Then, the
effect of GTF-11 characteristics performance on aircraft performance was
evaluated. A comparison between GTF-11 and conventional turbofan, RB211-
524B4, indicated that the aircraft can achieve a 13.1% improvement in fuel
efficiency by using the new concept engine.
Thirdly, a nacelle was designed for GTF-11 based on NACA 1-series and
empirical methods while the nacelle dimensions of conventional turbofan
RB211-525B4 were obtained by measure approach. Then, the installation thrust
losses caused by nacelle drags of the two engines were evaluated using ESDU
81024a. The results showed that the nacelle drags account for about 4.08%
and 3.09% of net thrust for GTF-11 and RB211-525B4, respectively.
Finally, the considerations of engine installation on a flying wing aircraft were
discussed and a preliminary disposition of GTF-11 on FW-11 was presented.
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Plumley, Ryan W. "Conceptual Assessment of an Oblique Flying Wing Aircraft Including Control and Trim Characteristics." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/31417.
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A method was developed to assist with the understanding of a unique configuration and investigate some of its stability and control attributes. Oblique wing aircraft concepts are a design option that is well understood, but has yet to be used in a production aircraft. Risk involved in choosing such a design can be averted through additional knowledge early in the concept evaluation phase.
Analysis tools commonly used in early conceptual level analysis were evaluated for applicability to a non-standard aircraft design such as an oblique flying wing. Many tools used in early analyses make assumptions that are incompatible with the slewed wing configuration of the vehicle.
Using a simplified set of tools, an investigation of a unique configuration was done as well as showing that the aircraft could be trimmed at given conditions. Wave drag was investigated to determine benefits for an oblique flying wing. This form of drag was reduced by the distribution of volume afforded by the slewing of the aircraftâ s wing. Once a reasonable concept was developed, aerodynamic conditions were investigated for static stability of the aircraft. Longitudinal and lateral trim were established simultaneously due to its asymmetric nature.Master of Science
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Mardanpour, Pezhman. "Effects of engine placement and morphing on nonlinear aeroelastic behavior of flying wing aircraft." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50268.
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Effects of engine placement on flutter characteristics of a very flexible high-aspect-ratio wing are investigated using the code NATASHA (Nonlinear Aeroelastic Trim And Stability of HALE Aircraft). The analysis was validated against published results for divergence and flutter of swept wings and found to be in excellent agreement with the experimental results of the classical wing of Goland. Moreover, modal frequencies and damping obtained for the Goland wing were found in excellent agreement with published results based on a new continuum-based unsteady aerodynamic formulation. Gravity for this class of wings plays an important role in flutter characteristics. In the absence of aerodynamic and gravitational forces and without an engine, the kinetic energy of the first two modes are calculated. Maximum and minimum flutter speed locations coincide with the area of minimum and maximum kinetic energy of the second bending and torsion modes. Time-dependent dynamic behavior of a turboshaft engine (JetCat SP5) is simulated with a transient engine model and the nonlinear aeroelastic response of the wing to the engine's time-dependent thrust and dynamic excitation is presented. Below the flutter speed, at the wing tip and behind the elastic axis, the impulse engine excitation leads to a stable limit cycle oscillation; and for the ramp kind of excitation, beyond the flutter speed, at 75% span, behind the elastic axis, it produces chaotic oscillation of the wing. Both the excitations above the flutter speed are stabilized, on the inboard portion of the wing.
Effects of engine placement and sweep on flutter characteristics of a backswept flying wing resembling the Horten IV are explored using NATASHA. This aircraft exhibits a non-oscillatory yawing instability, expected in aircraft with neither a vertical tail nor yaw control. More important, however, is the presence of a low frequency “body-freedom flutter” mode. The aircraft center of gravity was held fixed during the study, which allowed aircraft controls to trim similarly for each engine location, and minimized flutter speed variations along the inboard span. Maximum flutter speed occurred for engine placement just outboard of 60% span with engine center of gravity forward of the elastic axis. The body-freedom flutter mode was largely unaffected by the engine placement except for cases in which the engine is placed at the wing tip and near the elastic axis. In the absence of engines, aerodynamics, and gravity, a region of minimum kinetic energy density for the first symmetric free-free bending mode is also near the 60% span. A possible relationship between the favorable flutter characteristics obtained by placing the engines at that point and the region of minimum kinetic energy is briefly explored.
Effects of multiple engine placement on a similar type of aircraft are studied. The results showed that multiple engine placement increases flutter speed particularly when the engines are placed in the outboard portion of the wing (60% to 70% span), forward of the elastic axis, while the lift to drag ratio is affected negligibly. The behavior of the sub- and supercritical eigenvalues is studied for two cases of engine placement. NATASHA captures a hump body-freedom flutter with low frequency for the clean wing case, which disappears as the engines are placed on the wings. In neither case is there any apparent coalescence between the unstable modes. NATASHA captures other non-oscillatory unstable roots with very small amplitude, apparently originating with flight dynamics. For the clean-wing case, in the absence of aerodynamic and gravitational forces, the regions of minimum kinetic energy density for the first and third bending modes are located around 60% span. For the second mode, this kinetic energy density has local minima around the 20% and 80% span. The regions of minimum kinetic energy of these modes are in agreement with calculations that show a noticeable increase in flutter speed at these regions if engines are placed forward of the elastic axis.
High Altitude, Long Endurance (HALE) aircraft can achieve sustained, uninterrupted flight time if they use solar power. Wing morphing of solar powered HALE aircraft can significantly increase solar energy absorbency. An example of the kind of morphing considered in this thesis requires the wings to fold so as to orient a solar panel to be hit more directly by the sun's rays at specific times of the day. In this study solar powered HALE flying wing aircraft are modeled with three beams with lockable hinge connections. Such aircraft are shown to be capable of morphing passively, following the sun by means of aerodynamic forces and engine thrusts. The analysis underlying NATASHA was extended to include the ability to simulate morphing of the aircraft into a “Z” configuration. Because of the “long endurance” feature of HALE aircraft, such morphing needs to be done without relying on actuators and at as near zero energy cost as possible. The emphasis of this study is to substantially demonstrate the processes required to passively morph a flying wing into a Z-shaped configuration and back again.
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de, Castro Helena V. "Flying and handling qualities of a fly-by-wire blended-wing-body civil transport aircraft." Thesis, Cranfield University, 2003. http://hdl.handle.net/1826/119.
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The blended-wing-body (BWB) configuration appears as a promising contender for the next generation of large transport aircraft. The idea of blending the wing with the fuselage and eliminating the tail is not new, it has long been known that tailless aircraft can suffer from stability and control problems that must be addressed early in the design. This thesis is concerned with identifying and then evaluating the flight dynamics, stability, flight controls and handling qualities of a generic BWB large transport aircraft concept.
Longitudinal and lateral-directional static and dynamic stability analysis using aerodynamic data representative of different BWB configurations enabled a better understanding of the BWB aircraft characteristics and identification of the mechanisms that influence its behaviour. The static stability studies revealed that there is limited control power both for the longitudinal and lateral-directional motion. The solution for the longitudinal problem is to limit the static margins to small values around the neutral point, and even to use negative static margins. However, for the directional control problem the solution is to investigate alternative ways of generating directional control power. Additional investigation uncovered dynamic instability due to the low and negative longitudinal and directional static stability. Furthermore, adverse roll and yaw responses were found to aileron inputs.
The implementation of a pitch rate command/attitude hold flight control system (FCS) improved the longitudinal basic BWB characteristics to satisfactory levels, or Level 1, flying and handling qualities (FHQ). Although the lateral-directional command and stability FCS also improved the BWB flying and handling qualities it was demonstrated that Level 1 was not achieved for all flight conditions due to limited directional control power.
The possibility to use the conventional FHQs criteria and requirements for FCS design and FHQs assessment on BWB configurations was also investigated. Hence, a limited set of simulation trials were undertaken using an augmented BWB configuration. The longitudinal Bandwidth/Phase delay/Gibson dropback criteria, as suggested by the military standards, together with the Generic Control Anticipation Parameter (GCAP) proved possible to use to assess flying and handling qualities of BWB aircraft. For the lateral-directional motion the MIL-F-8785C criteria were used. Although it is possible to assess the FHQ of BWB configuartions using these criteria, more research is recommended specifically on the lateral-directional FHQs criteria and requirements of highly augmented large transport aircraft.
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Wang, Xiaoyang. "Aircraft fuel system prognostics and health management." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7214.
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This thesis contains the specific description of Group Design Project (GDP) and
Individual Research Project (IRP) that are undertaken by the author and form
part of the degree of Master of Science.
The target of GDP is to develop a novel and unique commercial flying wing
aircraft titled FW-11. FW-11 is a three-year collaborative civil aircraft project
between Aviation Industry Corporation of China (AVIC) and Cranfield University.
According to the market analysis result conducted by the author, 250 seats
capacity and 7500 nautical miles were chosen as the design targets.
The IRP is the further study of GDP, which is to enhance the competitive
capability by deploying prognostics and health management (PHM) technology
to the fuel system of FW-11. As a novel and brand-new technology, PHM
enables the real-time transformation of system status data into alert and
maintenance information during all ground or flight operating phases to improve
the aircraft reliability and operating costs. Aircraft fuel system has a great
impact on flight safety. Therefore, the development of fuel system PHM concept
is necessary.
This thesis began with an investigation of PHM, then a safety and reliability
analysis of fuel system was conducted by using FHA, FMEA and FTA.
According to these analyses, fuel temperature diagnosis and prognosis were
chosen as a case study to improve the reliability and safety of FW-11. The PHM
architecture of fuel temperature had been established. A fuel temperature
prediction model was also introduced in this thesis.
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Saeed, Burhan. "Exploring the aerodynamic characteristics of a blown-annular wing for V/STOL aircraft." Thesis, Brunel University, 2010. http://bura.brunel.ac.uk/handle/2438/5173.
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This research programme explores, theoretically and experimentally, a new liftsystem for Vertical/Short Take-off and Landing (V/STOL) Aircraft. It is based upon an annular wing wrapped around a centrifugal flow generator, potentially creating a vehicle with no external moving parts, reduced vehicle aerodynamic losses compared to previous V/STOL technologies and substantially eliminating induced drag. It is shown that such a wing works best with a thick aerofoil section, and appears to offer greatest potential at a micro-aerial vehicle scale with regard to fundamental performance parameter “lift to weight ratio”. Certain efficiency losses are encountered mainly occurring from annular flow expansion and problems with achieving acceptable blower slot heights. Experimental methods are described along with results, and a comparison shows that the experimental values remain below theoretical values, partly due to flow asymmetry but possibly also other factors. Symmetrical blowing, as initially hypothesised, was found to be impracticable; this suggested use of pure upper surface blowing with Coanda effect. The modified approach was further explored and proved viable. The ultimate goal of this work was to develop an understanding and the facility to integrate the annular-wing into a vehicle to achieve controlled powered flight. To serve the purpose, issues encountered on current and past V/STOL aircraft are being investigated to set a path for further research/development and to validate/justify the design of future V/STOL aircraft. Also, presented is a feasibility study where different physical scales and propulsion systems are considered, and a turbofan has shown to achieve the best performance in terms of Range and Endurance. This privilege allows one to accurately study the V/STOL technologies around.
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Bagheri, Shahriar. "Modeling, Simulation and Control System Design for Civil Unmanned Aerial Vehicle (UAV)." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-96458.
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Unmanned aerial systems have been widely used for variety of civilian applications over the past few years. Some of these applications require accurate guidance and control. Consequently, Unmanned Aerial Vehicle (UAV) guidance and control attracted many researchers in both control theory and aerospace engineering. Flying wings, as a particular type of UAV, are considered to have one of the most efficient aerodynamic structures. It is however difficult to design robust controller for such systems. This is due to the fact that flying wings are highly sensitive to control inputs. The focus of this thesis is on modeling and control design for a UAV system. The platform understudy is a flying wing developed by SmartPlanes Co. located in Skellefteå, Sweden. This UAV is particularly used for topological mapping and aerial photography. The novel approach suggested in this thesis is to use two controllers in sequence. More precisely, Linear Quadratic Regulator (LQR) is suggested to provide robust stability, and Proportional, Integral, Derivative (PID) controller is suggested to provide reference signal regulation. The idea behind this approach is that with LQR in the loop, the system becomes more stable and less sensitive to control signals. Thus, PID controller has an easier task to do, and is only used to provide the required transient response. The closed-loop system containing the developed controller and a UAV non-linear dynamic model was simulated in Simulink. Simulated controller was then tested for stability and robustness with respect to some parametric uncertainty. Obtained results revealed that the LQR successfully managed to provide robust stability, and PID provided reference signal regulation.
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Deslich, Joshua. "Effects of a Bell-Shaped Lift Distribution on an Oblique Flying Wing and its Impact on Aerodynamic Performance." University of Dayton / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1590560243607956.
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Al-Kayiem, Hussain Hammod. "Separated flow on a high lift wing : a study of the characteristics of the separated flow region on a lift wing under normal and wing/body conditions by means of a flying hot-wire technique." Thesis, University of Bradford, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235558.
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Masiulis, Paulius. "Bepiločio skraidančio sparno aerodinaminių charakteristikų tyrimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20140625_094638-60072.
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Šiame darbe nagrinėjamos bepiločio skraidančio sparno aerodinaminės charakteristikos. Pasirinktas sparno profilis EPPLER 328. Pirmiausia išanalizuojami skaitiniai aerodinaminių charakteristikų tyrimo metodai. Atlikus skaičiavimus pagal pasirinktus aspektus, naudojant programą XFLR5 gauti duomenys apibendrinami bei išanalizuojami. Ištirtos keliamosios jėgos koeficientų, pasipriešinimo jėgos koeficientų, aerodinaminės kokybės reikšmės esant atitinkamiems atakos kampams. Naudojantis tyrimo rezultatais padarytas bepilotis skraidančio sparno orlaivis ir atlikti skrydžiai. Visa informacija apibendrinama ir pateikiamos gautų rezultatų išvados. Darbo apimtis – 66 p. teksto be priedų, 39 paveikslai, 6 lentelės, 24 bibliografiniai šaltiniai.The investigation analyzes unmanned flying wing aerodynamic characteristics. Choosen airfoil EPPLER 328. Firstly, analyzing theoretical calculation methods. All relative data compared and analyzed after calculation with program XFLR5. Analyzed lift force coefficient, drag force coefficient, aerodynamic coefficient under realative angles of attack. Unmanned flying wing was built using the results of compared and analyzed aerodynamic data and test flights were made. All information summarized and produced conclusion. Thesis consists of: 66 p. text without appendixes, 39 pictures, 6 tables, 24 bibliographical entries.
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Zhou, Weiguo. "Cabin environment and air quality in civil transport aircraft." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7305.
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The cabin environment of a commercial aircraft, including cabin layout and the quality of air supply, is crucial to the airline operators. These aspects directly affect the passengers’ experience and willing to travel. This aim of this thesis is to design the cabin layout for flying wing aircraft as part of cabin environment work, followed by the air quality work, which is to understand what effect the ECS can have in terms of cabin air contamination.
The project, initially, focuses on the cabin layout, including passenger cabin configuration, seat arrangement and its own size due to the top requirements, of a conventional aircraft and further into that of a flying wing aircraft. The cabin work in respect of aircraft conceptual design is discussed and conducted by comparing different design approaches. Before the evaluation of cabin air quality, an overall examination of the main ECS components involved in the contaminants access will be carried on and, therefore, attempt to discover how these components influence the property of the concerned contaminants. By case study in the B767 ECS, there are some comments and discussions regarding the relationship between the cabin air contaminations and the passing by ambient environment. The thesis ends up with a conclusion explaining whether or not the contaminated air enters the occupants’ compartments on aircraft and proposing some approaches and engineering solutions to the continue research.
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Pettersson, Emil. "Design of a drone system for maritime search and rescue missions." Thesis, KTH, Flygdynamik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290180.
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The work summarized in this report aims to investigate how a drone airplane design can be optimized to create a safer and more efficient sea rescue by providing staff with an early picture, performing search missions and aiding communication through visual contact. A flying wing is in theory one of the most efficient designs for a fixed wing aircraft, at the same time as it also offers high structural efficiency for its given size. In this report, an overview of aerodynamics, stability and flying quality for a flying wing is discussed and analysed. XFLR5 was used for this project, and a comparison between the analytical results and wind tunnel test data for a prototype was conducted. A strong correlation was found between the theoretical analyses and the wind tunnel data. A simple control solution using only one set of elevons has been proposed and simulated, resulting in Level 1 dynamic stability for all modes except Dutch-roll (where the drone’s damping is 𝜁𝑑𝑟=0.07 and the requirement for Level 1 is 𝜁𝑑𝑟=0.08). For the range of angle of attack used, the autopilot system will have to trim the drone in flight to achieve stability. As the drone only has one set of control surfaces there will be a loss of efficiency in this scenario, meaning that 𝐶𝐿/𝐶𝐷 = 15.7 for loiter speed of 15 𝑚/𝑠 and 7.9 for full speed at 35 𝑚/𝑠. In regular flight, with a total mass <1 𝑘𝑔, the drone is able to fly at full speed for 214 𝑘𝑚 or loiter for 6.3 ℎ with a battery package of 130 𝑊ℎ. As such, the objective of this project was achieved, and the proposed design met the given requirements.betet som sammanfattas i denna rapport syftar till att undersöka huruvida ett drönar-flygplan bäst kan utformas för att skapa en säkrare och effektivare sjöräddning genom att ge räddningspersonalen en tidig överblick, utföra sökuppdrag och bistå till kommunikation genom visuell kontakt. En flygande vinge är i teorin en av de mest effektiva konstruktionerna för ett flygplan, likaså erbjuder den en hög strukturell effektivitet för en given storlek. I denna rapport diskuteras och genomförs en översikt över aerodynamik, stabilitet och flygkvalitet hos en flygande vinge. XFLR5 användes för detta projekt, och en jämförelse mellan analysresultaten och ett vindtunneltest med en prototyp genomfördes. I allmänhet är överenskommelsen mellan de teoretiska analyserna och vindtunneldatan god. En enkel lösning som enbart består av en uppsättning kontrollytor har föreslagits och simulerats, vilket resulterar i en Nivå 1 dynamisk stabilitet för alla lägen utom Dutch-roll, där drönarens dämpning är 𝜁𝑑𝑟 = 0.07 och kravet för Nivå 1 är 𝜁𝑑𝑟 = 0.08. Autopilotsystemet behöver trimma drönaren under flygning för att uppnå nödvändig stabilitet för det spann av attackvinklar som används, med endast en uppsättning kontrollytor, vilket minskar effektiviteten för BWB-drönaren till 𝐶𝐿/𝐶𝐷=15.7 för cirkuleringshastigheten på 15 𝑚/𝑠 och 7.9 för full hastighet vid 35 𝑚/𝑠. Drönaren kan flyga i full hastighet i 214 𝑘𝑚 eller cirkulera runt olycksplatsen under 6.3 timmar med ett batteripaket på 130 𝑊ℎ, med en vikt som är lägre än 1 𝑘𝑔. Målen med detta projekt uppnåddes och drönaren utformades enligt kraven.
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Mohd, Nasir Mohd Nazri [Verfasser], Tropea [Akademischer Betreuer] Cameron, and Lehmann [Akademischer Betreuer] Fritz-Olaf. "Dynamics of high-speed-resolved wing and body kinematics of freely flying houseflies responding to directed and undirected air turbulence / Mohd Nazri Mohd Nasir ; Tropea Cameron, Lehmann Fritz-Olaf." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2017. http://d-nb.info/1123729441/34.
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Voß, Arne [Verfasser], Andreas [Akademischer Betreuer] Bardenhagen, Andreas [Gutachter] Bardenhagen, Wolf-Reiner [Gutachter] Krüger, and Hartmut [Gutachter] Zingel. "Design and structural optimization of a flying wing of low aspect ratio based on flight loads / Arne Voß ; Gutachter: Andreas Bardenhagen, Wolf-Reiner Krüger, Hartmut Zingel ; Betreuer: Andreas Bardenhagen." Berlin : Technische Universität Berlin, 2020. http://d-nb.info/1208764500/34.
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Ekstam, Hanna, and Benjamin Quarmochi. "Design av infästningsanordning för virveldämpare på drönare." Thesis, Linnéuniversitetet, Institutionen för maskinteknik (MT), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-106215.
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Arbetet syftar till att ta fram en hållbar infästning för virveldämpare till SSRS drönare av modell flygande vinge. Drönaren är specifikt framtagen för att användas till maritima sök och räddningsuppdrag och för att bidra till att utöka den svenska kustens säkerhet. Arbetet studerar ett landningsscenario för drönaren och utifrån detta tas en ny infästning fram. Infästningen av virveldämparen skall vara lätt att hantera för personalen, kräva minimalt med reparation och hålla för 50 landningar. Infästningen skall kunna utlösa och separera virveldämparen från vingen om det under landningen uppstår så stora krafter att dessa komponenter riskerar att ta skada. Arbetet följer DRM-struktur och syftar till att ta fram en prototyp med hjälp av en uttömmande idégenerering utförd med metoderna Speedstorming, Brainstorming och SCAMPER. Konceptsållningen sker med hjälp av anpassade poängsättningsmetoder och Pugh-analys. Det resulterande konceptet bestämmer vilka dimensioner som krävs för att kunna utföra hållfasthetsberäkningar på den valda infästningen, därefter skapas en prototyp vilken används för att utföra hållfasthetstester. De utförda beräkningarna och testerna gav olika resultat och den därav dragna slutsatsen medförde att materialegenskaper rörande elastisk deformation och variabler på hållfasthetstestet ej har beaktas. Testerna visade att den framtagna prototypen av expanderad polypropen hanterade de förutsedda krafterna väl även om testerna inte kunde utföras under helt verklighetstrogna landningsförhållanden. Slutresultatet av projektarbetet är att den framtagna infästningen av virveldämparen har, utifrån tillgängliga testningsmetoder, påvisat önskade egenskaper och att utförligare tester behöver genomföras för att avgöra om den uppfyller samtliga produktkrav.This work is aimed at producing durable attachments for winglets on a drone, model flying wing, owned by the SSRS. The drone is specifically developed to be used for maritime search and rescue missions and to contribute to increasing the security along the Swedish coast and major inland lakes. During this work only one landing scenario by the drone was studied while creating the attachments, which required to be easy to handle, minimal to no repair work and a durability for 50 landings. The attachments also need to be able to release in case of excessive force during landing which risks jeopardizing the integrity of the wing or winglet. The work followed the DRM-structure and aimed to create a prototype through an exhaustive idea generation technique in three steps using the methods Speedstorming, Brainstorming and SCAMPER. All of these methods go through voting, Pugh analysis and concept screening. After one concept had been singled out its dimensions were decided on and used in calculations to determine its strength. From this information a physical winglet attachment prototype made of expanded polypropylene was created and used in strength and durability tests. Calculations and tests were found to have varying results and the conclusion was made that the material properties regarding elastic deformation and test variables most likely had not fully been taken into account. The tests failed to generate a realistic landing scenario given the requirements but still gave a positive result concerning the prototype's ability to absorb shock loads at landing. This work has resulted in a preliminary winglet attachment prototype which through testing has shown satisfying shock absorbing abilities, and that further testing is required to decide whether the attachment can meet all of the set product requirements.
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Silva, Rafael. "Projeto conceptual de uma aeronave pequena de baixo custo para aplicação em controlo cooperativo." Master's thesis, Academia da Força Aérea, 2020. http://hdl.handle.net/10400.26/39752.
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Tendo como objetivo principal a busca por uma estrutura capaz de satisfazer as necessidades previstas para o desenvolvimento do controlo cooperativo, integrado no plano de Investigação e Desenvolvimento do Centro de Investigação da Academia da Força Aérea, encontra-se na presente dissertação um modelo de aeronave proposto e validado.
Após serem salientados os requisitos essenciais ao sistema de controlo cooperativo, é apresentado um tipo de arquitetura do qual se destacam os sistemas de voo associados à mesma. Deste modo, após dimensionar o corpo onde estarão presentes os sistemas, opta-se por um design estrutural de asa voadora, em espuma, com uma caixa central fabricada através de manufatura aditiva.
Através de uma comparação com outros modelos idênticos e métodos analíticos para valores de carga alar e power loading, desenvolve-se um modelo computacional da aeronave final, justificando os perfis alares a utilizar na sua elaboração. O modelo final desenvolvido é caraterizado por um design de asa voadora, com peso à descolagem de 1,2 kg e uma envergadura de 1 m. Este modelo é validado através de uma ferramenta computacional, executando-se uma caraterização aerodinâmica e uma análise de estabilidade.
Posteriormente, é desenvolvido um modelo à escala de 1/1,25 para ser utilizado no túnel aerodinâmico. Os dados obtidos são comparados com a simulação computacional, validando a aeronave segundo este método.
Finalmente, é desenvolvido um protótipo real do modelo sujeitando-o a ensaios em voo por forma a ser validado através de um método prático.
Esta dissertação satisfaz assim a necessidade da estrutura propondo uma aeronave de construção rápida, baixo custo e capaz de responder às necessidades de um controlo cooperativo, validada segundo uma análise teórica, computacional com base no XFLR5, experimental através do túnel aerodinâmico e prática através de ensaios em voo.This paper presents a validated aircraft structure capable of satisfying the demands of swarm robotics, integrated on the ideas of the Investigation and Development plan of the Portuguese Air Force Academy Research Centre. Once the necessities of a swarm robotics system are presented, associated to a specific electric structure, the flight systems able to fulfil the purpose are revealed. After being capable of sizing and modeling the body where all these systems will be allocated, the flying wing design is in order. This wing is made with foam on the majority of its structure, and the main central body requires an additive manufacturing process. Comparing with other small sized aircraft and analytic methods to calculate the values of wing and power loading, a final computational model is developed justifying the airfoils used on its design. The final project is a flying wing with a take-off weight of 1,2 kg and a wingspan of 1 m. It is validated through a computer aerodynamic tool analyzing its behavior concerning its aerodynamics and stability. Afterwards, a scale model from 1/1,25 is created in order to be used on the wind tunnel. Data from these tests is compared with the computer aerodynamic tool validating the aircraft throughout this method. Subsequently a real size prototype is exposed to flight tests validating once again the project. This being said, the final objective is achieved, suggesting an aircraft, theoretically validated and reinforced with wind tunnel and flight tests, fast-constructed, low budget and able to answer the requirements of a swarm robotics system.
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GARBUGLIA, FRANCESCO. "L'uso di sistemi aeromobili a pilotaggio remoto per la diagnosi non distruttiva di sistemi energetici." Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/253140.
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L’uso dei sistemi aeromobili a pilotaggio remoto per la diagnosi non distruttiva di sistemi energetici necessita di un approccio quantitativo e sistematico. L’ispezione mediante drone di pale di turbine eoliche nel visibile e nell’infrarosso presenta dei notevoli vantaggi in termini di tempi, sicurezza e qualità rispetto alla tradizionale ispezione con un operatore su fune. Per questo si fa una review delle opportunità scientifiche e commerciali attuali. Si considera quindi la necessità di usare i sistemi aeromobili a pilotaggio remoto anche per analisi di tipo ambientale all’interno del progetto A.D.E.L.E. (Aerial Drone for EnvironmentaL and Energy Researches). Si progetta e sviluppa con questo intento un velivolo VTOL (Vertical Take off and Landing), cioè ad atterraggio e decollo verticale. L’ala fissa è portante nel volo in orizzontale mentre il sostentamento a punto fisso è garantito da due coppie di motori controrotanti poste all’interno delle ali abbinate ad una terza coppia posteriore per il bilanciamento. Il movimento in orizzontale si effettua mediante un propulsore posto al di sopra del velivolo. Si tratta di un velivolo “tuttala” con ala a freccia e con una coda a V. All’interno dell’ala vengono posti tutti gli strumenti di misura che sono intercambiabili e consentono diverse tipologie di analisi: ambientale, delle fonti di rumore, iperspettrale, nell’ambito delle energie rinnovabili. Si progetta il velivolo dall’analisi dei profili alla pianta, considerando una serie di accorgimenti aerodinamici necessari al volo e il dimensionamento strutturale del longherone dell’ala. Si realizza poi un modello in scala dello stesso per la verifica di parametri non riscontrabili mediante simulazioni numeriche. I primi test di volo positivi dimostrano la fattibilità dell’approccio. A questo modello si aggiunge la progettazione di un drone quadricottero per le analisi di specie chimiche nell’aria che ha un payload non compatibile con il velivolo precedente.The use of Remotely Piloted Airplane Systems to do Non Destructive Testing Techniques on energy systems needs a more quantitative and systematic approach. The inspection with a drone of wind turbine’s blades in visible and infrared range shows considerable advantage in terms of time, safety and quality compared with current rope access inspection. Then a review of present scientific and commercial opportunities follows. The use of drones for environmental research and energy research has been developed through the project A.D.E.L.E. (Aerial Drone for EnvironmentaL and Energy Research). A VTOL remotely piloted aircraft (Vertical Take Off and Landing) is designed into this project. We combine fixed wing to give lift in horizontal flight and vertical electrical propellers to hover. The prototype has two couples of rotating propellers into the wing and a third balancing one on the rear side. An electric turbine on the upper part of the wing gives horizontal propulsion. The airplane is a “Flying wing” with a swept wing and a V-Tail. The drone is meant to do different inflight activities with interchangeable measurement devices: geographical, environmental, noise source detection and hyperspectral analysis. The design goes from the airfoils to the shape of the wing and a series of aerodynamic choices that allows flight combined with the structural design of the wing spar cap. Then a scale model has been realized to verify experimentally what is difficult or impossible to predict by simulation. First successful flight tests give evidence that the method is right. Furthermore a quadcopter drone has been designed for the environmental mission that has greater payloads to sample and analyze ambient air.
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Shinagawa, Yuto. "Propulsion considerations for supersonic oblique flying wings." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35565.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2006.Includes bibliographical references (p. 111-113).
Propulsion considerations unique to the supersonic oblique flying wing, including cycle selection, sizing, and integration were investigated via the development and interrogation of aerodynamic and propulsive synthesis models. These models were an amalgamation of computational tools (MSES), linearized theory, parametric estimation, and quasi D thermodynamic cycle analysis. Lift-to-drag ratio, thrust specific fuel consumption, and nacelle wave drag were examined as intermediate figures of merit that would ultimately impact the final performance metric-namely, range parameter and specific excess power. It was found that higher bypass ratio engines could yield an increase in the range parameter up until a critical mach number, above which the increasing nacelle drag would offset the TSFC reductions to yield a net degradation in range performance. Between the baseline TF30-type cycle and its BPR 2.4 modified variant, this critical mach number was found to be at approximately M 2.0 for TT4/TT2 = 5, and M 2.2 for TT4/TT2 = 6.
(cont.) The OFW whose engine was sized for supersonic cruise was also found to have less excess power throughout the low speed regime and hence, longer climb and acceleration times than a comparable symmetric-wing supersonic aircraft. It was concluded that the OFW's reduced drag at supersonic cruise mitigates the gross oversizing of the engine that is common and inevitable for conventional supersonic aircraft at takeoff. Preliminary investigation of the turntable-mounted engine and slot-inlet have demonstrated their feasibility as viable engine integration concepts, but has also revealed the need for integrated design solutions, such as the development of a novel flat-top airfoil, aggressive S-ducts, and in general, a highly compact engine.
by Yuto Shinagawa.
S.M.
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Murthy, Raghuram Ananda, University of Western Sydney, and of Mechatronic Computer and Electrical Engineering School. "Dynamics of tethering cables for a flying electric generator." THESIS_XXX_MCEE_Murthy_R.xml, 2000. http://handle.uws.edu.au:8081/1959.7/674.
Full textAbstract:
The dynamics of a tether cable for a flying wind generator, employed to generate electricity by utilising the high velocity jet-stream winds in the troposphere, is analysed. A non-linear mathematical model for the study of the dynamics of the cable is described by a partial differential equation, which is solved analytically without damping. For unsteady and damped states, ordinary differential equations are obtained by adopting a discrete analysis approach, which are solved numerically with the aid of MATLAB software. Solutions are found for a range of lumped masses to represent the cable and each solution is verified against a previous case. Likewise, the result for the three masses is checked against the cable using a single lumped mass. The analysis is extended to seven discrete masses. This research highlights the dynamic behaviour of the cable subjected to wind gusts on the rotors and it also represents an appreciable input to the flying wind generator concept. The dynamic behaviour of the cable is critical for a flying electric generator.Master of Engineering (Hons)
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Murthy, Raghuram Ananda. "Dynamics of tethering cables for a flying electric generator." Thesis, View thesis View thesis, 2000. http://handle.uws.edu.au:8081/1959.7/674.
Full textAbstract:
The dynamics of a tether cable for a flying wind generator, employed to generate electricity by utilising the high velocity jet-stream winds in the troposphere, is analysed. A non-linear mathematical model for the study of the dynamics of the cable is described by a partial differential equation, which is solved analytically without damping. For unsteady and damped states, ordinary differential equations are obtained by adopting a discrete analysis approach, which are solved numerically with the aid of MATLAB software. Solutions are found for a range of lumped masses to represent the cable and each solution is verified against a previous case. Likewise, the result for the three masses is checked against the cable using a single lumped mass. The analysis is extended to seven discrete masses. This research highlights the dynamic behaviour of the cable subjected to wind gusts on the rotors and it also represents an appreciable input to the flying wind generator concept. The dynamic behaviour of the cable is critical for a flying electric generator.
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Murthy, Raghuram Ananda. "Dynamics of tethering cables for a flying electric generator /." View thesis View thesis, 2000. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030509.162730/index.html.
Full textAbstract:
Thesis (M.Sc. (Hons)) -- University of Western Sydney, 2000."Thesis submitted to the University of Western Sydney, Nepean for the degree of Master of Engineering (Hons)" "School of Mechatronics, Computer and Electrical Engineering, December 2000" Includes bibliographical references (leaves 111-113).
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Raghavan, Brijesh. "Flight Dynamics and Control of Highly Flexible Flying-Wings." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/26829.
Full textAbstract:
High aspect-ratio flying wing configurations designed for high altitude, long endurance missions are characterized by high flexibility, leading to significant static aeroelastic deformation in flight, and coupling between aeroelasticity and flight dynamics. As a result of this coupling, an integrated model of the aeroelasticity and flight dynamics has to be used to accurately model the dynamics of the flexible flying wing. Such an integrated model of the flight dynamics and the aeroelasticity developed by Patil and Hodges is reviewed in this dissertation and is used for studying the unique flight dynamics of high aspect-ratio flexible flying wings. It was found that a rigid body configuration that accounted for the static aeroelastic deformation at trim captured the predominant flight dynamic characteristics shown by the flexible flying wing. Moreover, this rigid body configuration was found to predict the onset of dynamic instability in the flight dynamics seen in the integrated model. Using the concept of the mean axis, a six degree-of-freedom reduced order model of the flight dynamics is constructed that minimizes the coupling between rigid body modes and structural dynamics while accounting for the nonlinear static aeroelastic deformation of the flying wing. Multi-step nonlinear dynamic inversion applied to this reduced order model is coupled with a nonlinear guidance law to design a flight controller for path following. The controls computed by this flight controller are used as inputs to a time-marching simulation of the integrated model of aeroelasticity and flight dynamics. Simulation results presented in this dissertation show that the controller is able to successfully follow both straight line and curved ground paths while maintaining the desired altitude. The controller is also shown to be able to handle an abrupt change in payload mass while path-following. Finally, the equations of motion of the integrated model were non-dimensionalized to identify aeroelastic parameters for optimization and design of high aspect-ratio flying wings.Ph. D.
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Christiansen, Reed Siefert. "Design Of An Autopilot For Small Unmanned Aerial Vehicles." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd445.pdf.
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Molter, Christian [Verfasser]. "Development of a Flying Wind Measurement System for Collective Operation / Christian Molter." München : Verlag Dr. Hut, 2020. http://d-nb.info/1220568155/34.
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Tomić, Teodor [Verfasser]. "Model-based control of flying robots for robust interaction under wind influence / Teodor Tomić." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2018. http://d-nb.info/1172414645/34.
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Molter, Christian [Verfasser], and Po Wen [Akademischer Betreuer] Cheng. "Development of a flying wind measurement system for collective operation / Christian Molter ; Betreuer: Po Wen Cheng." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1220692840/34.
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Metalli, Matteo. "Sviluppo di un modello di drone di tipo flying wings in ambiente FlightGear interfacciato con autopiloti di Arduino implementati in Simulink." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3009/.
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Fraser, Neil James. "Mechanisms for wintertime fjord-shelf heat exchange in Greenland and Svalbard." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31289.
Full textAbstract:
No region has felt the effects of global climate change more acutely than the cryosphere, which has changed at an unprecedented rate in the past two decades. The scientific consensus is that these changes are driven largely by increasing ocean heat content at high latitudes. In southeast Greenland, acceleration and retreat of the marine-terminating glaciers contributes significantly towards global sea level rise. Circulation in the fjords which accommodate these glaciers is thought to be driven both by freshwater input and by barrier wind-driven shelf exchange. Due to a scarcity of data, particularly from winter, the balance between these two mechanisms is not fully understood. In Svalbard, increasing water temperature has decimated sea ice cover in many of the fjords, and had substantial implications for the local ecosystem. While there is a relatively comprehensive literature on shelf exchange mechanisms in Svalbard fjords, questions remain over how the internal circulation interacts with exchange mechanisms. The region shares a similar underwater topography and oceanographic setting with southeast Greenland, with marine-terminating glaciers in close proximity to warm Atlantic waters, and results from Svalbard can hence be used to inform studies of high-latitude fjord-shelf exchange in a broader context. A realistic numerical model was constructed with the aim of better understanding the interaction between Kangerdlugssuaq Fjord and the adjacent continental shelf, and quantifying heat exchange during winter. The model was initially run in an idealised configuration with winter climatological forcing fields, incorporating a parameterisation for melting at the terminus, and used to test the impact of barrier wind events. The Earth's rotation played a crucial role in the nature of the circulation and exchange in the fjord, with inflow on the right (looking up-fjord) and outflow on the left. While the heat delivered into the fjord-mouth was smaller than that observed in summer, the background internal circulation was found to efficiently distribute waters through the fjord without external forcing, and the heat delivered to the glacier terminus was comparable to summer values. Barrier winds were found to excite coastally-trapped internal waves which propagated into the fjord along the right-hand side. The process was capable of doubling the heat delivery. The process also enhanced the background circulation, likely via Stokes' Drift. The model was then adapted to simulate winter 2007-08 under historical forcing conditions. Time series of glacial melt rate, as well as the heat flux through fjord cross-sections, were constructed and compared to the variability in wind forcing. Long periods of moderate wind stress were found to induce greatly enhanced heat flux towards the ice sheet, while short, strong gusts were found to have little influence, suggesting that the timescale over which the shelf wind field varies is a key parameter in dictating wintertime heat delivery from the ocean to the Greenland Ice Sheet. An underwater glider was deployed to Isfjorden, a large fjord system in Svalbard, to measure the temperature, salinity and depth-averaged currents over the course of November 2014. Like in Kangerdlugssuaq, the circulation in Isfjorden was found to be heavily influenced by the Earth's rotation and by wind activity both locally and on the shelf. The combination of hydrography and high-resolution velocity data provided new insights, suggesting that the approach will be useful for studying high-latitude fjords in the future.
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Anderson, Elaine Susan. "Flying on the wings of trust : the story of the Delta farmland and wildlife trust an example of collaborative community based resource management." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/22482.
Full textAbstract:
Competition over resources is threatening both agricultural viability and wildlife habitat around
the world. One of the ways this problem can be addressed is through agri-environmental non-government organizations (NGOs) that practice community based collaborative resource
management. However, there is a lack of academic research on both the formation and development of agri-environmental NGOs in First World industrialized nations and the role that policy plays in their formation and development. It is important to understand how policy affects the formation and development of such organizations in order to address any policy gaps that may exist. My research examines how a community in conflict acknowledged the potential loss of both agricultural and wildlife resources and came together to identify ways to share resources more equitably. Since 1993, the Delta Farmland and Wildlife Trust (DFWT) has been working with farmers and environmentalists to balance the needs of wildlife with the needs of farmers. The DFWT shares the cost of specific management practices that benefit agriculture and wildlife. My research involved face-to-face interviews with 28 individuals who had been involved in the formation and/or development of the DFWT. Content analysis was used to identify common themes in the interviews. Secondary sources of information were
reviewed to triangulate the results. The formation of the DFWT came about due to a number of
conflicts occurring in Delta at the time. The conflicts were having a negative impact on both
agricultural and wildlife habitat viability. The key driving force in the formation of the DFWT
appeared to be the willingness of agricultural and conservation interests to work together.
Government policy appears to have enabled the formation of the DFWT. However, policy may
be impeding the development of the DFWT by limiting the ability of the DFWT to provide
agri-environmental stewardship programs in an optimal manner. Agri-environmental policies
from three countries were reviewed and a variety of policies that could be used to encourage
agri-environmental stewardship in Canada were identified. This research will be of value to
individuals and organizations interested in collaborative community based resource
management as well as to those interested in developing supportive agri-environmental policy.
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Reuveni, Yifat. "Iron wings and flying bodies: ideology and practice in the new economy - a case study of the middle-class workforce in the hi-tech industry." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92241.
Full textAbstract:
At the end of the last century, a promising mode of economy emerged. Resting on developments in information and communication technologies, it became known as the New Economy. It offered a liberating ethos of work, claiming to value such traits as autonomy, flexibility, inventiveness and entrepreneurial spirit. Replacing the aloofness of mechanist Taylorism and the alienation of Fordist mass production, it succeeded in recruiting a young, educated and enthusiastic workforce that was willing to work long days in pursuit of success.This study investigates the commitment of the white-collar workforce to the New Economy. It examines the persuasive practices these employees use in order to contribute, consciously or not, to this economic enterprise. The theory of reflexive modernism is used to examine whether this new system actually represents an increase in autonomy at work, or if it is another form of neo-liberal manipulation that uses the exciting aura of technology and youth to gloss over the grim realities of work. The value placed on individualization by the New Economy work culture illustrates this dichotomy, pitting the illusion of autonomy (self-management) against a dangerous kind of individualism (self-fulfillment). This is arguably one of the triumphs of the neo-liberal ethos of individualization: transforming collective responsibility into self-responsibility, thus neglecting the industry's accountability towards its workers and the social sphere.
This study integrates in-depth interviews with hi-tech white-collar Western workers with several theoretical and disciplinary approaches to the study of work, including those of cultural studies, management studies, and communication studies. It examines the history of technological revolutions and work cultures, the evolution of the white-collar class, the post-Fordist work ethic and the influence of economic liberalism, in order to study the integration of the workforce within the New Economy and to understand the rationales that justify this integration.
By exposing the manipulative techniques that create a positive ethos of work, we can increase understanding of the consequences of the new global information economy. This study provides both scholars and employees operating in this economy an active channel into fomenting change towards a more balanced, humane and sane work ethic and culture.
Fondée sur les développements des technologies d'informations et de communication, un mode d'économie prometteur, appelé la nouvelle économie a émergé à la fin du siècle dernier. Cette dernière permet un ethos de travail libérateur, prônant les valeurs telles que : l'autonomie, la souplesse, l'inventivité et l'esprit d'entreprise. Remplaçant le manque d'implication observé dans le Taylorisme mécanique et l'aliénation de la production de masse du Fordisme, la nouvelle économie a réussi à recruter une main d'uvre jeune, éduquée et enthousiaste, disposée à travailler de longues journées dans le but de réussir.
Cette étude porte sur l'engagement des employés dans la nouvelle économie. Elle examine les usages de ces employés visant à contribuer, consciemment ou inconsciemment à cette entreprise économique. La théorie de la modernité réflexive est utilisée pour examiner si ce nouveau système représente en fait une augmentation de l'autonomie dans le monde du travail, ou s'il s'agit d'une autre forme de manipulation néo-libérale qui se sert de l'aura exaltant de la technologie et de la jeunesse pour dissimuler les sombres réalités du travail. La valeur donnée à l'individualisation par la culture du travail de la nouvelle économie illustre cette dichotomie, en contredisant l'illusion de l'autonomie (autogestion) par un type d'individualisme dangereux (réalisations personnelles). C'est sans doute un des triomphes de l'ethos néo-libéral de l'individualisation: transformant la responsabilité collective en responsabilité personnelle, négligeant par conséquent la responsabilité de l'industrie envers ses employés et la sphère sociale. Cette étude intègre des entretiens approfondis avec des employés occidentaux du secteur de la technologie de pointe, et comporte aussi plusieurs approches théoriques et disciplinaires de l'étude du travail, y compris dans les domaines des études culturelles, de gestion et de communication. Elle examine l'histoire des révolutions technologiques et des cultures du travail, l'évolution des employés, l'éthique du travail post-fordiste et l'influence du libéralisme économique afin d'étudier l'intégration de la main d'uvre dans la nouvelle économie et de comprendre les raisonnements qui justifient cette intégration.
En exposant les techniques manipulatoires qui créent un ethos de travail positif, nous pouvons approfondir notre compréhension des conséquences de la nouvelle économie d'information globale. Cette étude fournit à la fois aux universitaires et aux employés participant activement à cette économie une voie active pour inciter au changement vers une éthique et une culture du travail plus équilibrée, plus humaine et plus saine.
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Hu-MingShen and 沈胡茗. "Lateral Stability Control Design for the Flying Wing." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/98651109242224500987.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
101
This thesis focuses on the lateral stability control design for an unsteady tailless aircraft. The aircraft configuration reference design is based on Northrop YB-49 which was developed by Northrop Corporation. The aerodynamic coefficients were determined by DATCOM software and the results show that the stability of the tailless aircraft is unsteady. Instead of traditional root locus method, the eigenvalues assignment method suitable for multi-input multi-output (MIMO) systems is adopted for the analysis of two forms of control designs, P and PID. The equations of motion are linearized and Laplace transform is used to transform the linear differential equations into a set of algebraic equations. For P control, the differential equations are of the fourth order and therefore have four eigenvalues to be assigned. For PID control, the differential equations are of the eighth order and therefore have eight eigenvalues. However, since two of the eigenvalues are always zero, there are only six eigenvalues which can be assigned. This thesis primarily analyzes the gains for P and PID control designs by the eigenvalue assignment method. After the gains are determined, simulations are conducted for the flight control system to check if the response characteristics and tracking performances are satisfied.
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Tsung-HsienLi and 李聰賢. "Longitudinal Stability Control Design for the Flying Wing." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24924446406879533272.
Full textAbstract:
碩士國立成功大學
航空太空工程學系碩博士班
101
In this thesis, the major objective is to synthesizes the longitudinal stability control design for a flying-wing type aircraft. The flying-wing geometrical configuration is established and the digital DATCOM program is used to estimate its aerodynamic coefficients in order to analyze its stability characteristics and tracking performance. The results show that its stability characteristics is poor and a control system is needed to be designed in order to enhance the stability. It is known that PID method is very useful for control design, as it can improve the transient state characteristics and track a constant command input. However, when the system is multiple-input and multiple-output (MIMO) as for the case in this thesis, it is unhelpful to use the conventional root locus method. Therefore, in this thesis, the eigenvalue assignment method which can be used in the multiple-input and multiple-output (MIMO) system is adopted. In using the eigenvalue assignment method, the characteristic equation of the system is established and the coefficients are compared with those of the polynomial equation formed from the desired eigenvalues. A set of nonlinear algebraic equations are thus established for the control gains and solved by using the Newton-Raphson iterative method. After the gains are determined, the feedback control system is simulated. From the simulation results, it is found that the output response in longitudinal system of flying wing has been significantly improved with the PID control.
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LIAO, CHIEN-HSUN, and 廖建薰. "Preliminary Flight Performance Analysis of a Flying-Wing UAV." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/jfwvx2.
Full textAbstract:
碩士逢甲大學
智能製造與工程管理碩士在職學位學程
107
The technology of design and manufacture of Unmanned Aerial Vehicle (UAV), has been rapidly improved in the world. At present, the industry in which UAV are used is quite extensive. Take the military mission as an example, for the execution of short-range front-line reconnaissance missions and even long-range reconnaissance missions, it is necessary to have a carrier with excellent aerodynamic efficiency for the mission, regardless of whether the power system of the vehicle is equipped with an internal combustion engine or an electric brushless DC (BLDC) motor. Even the operational efficiency is high, the endurance limit of the UAV is still determined by the design of aerodynamic shape, especial for the un-matured development of current battery. The major objectives of this thesis are to simulate the flow field of the BLDC power’s UAV, and solve its lift and drag. Then, modified the wing shape to see if the aerodynamic performance is better than the original design. At first, the execute procedures are using SolidWorks to construct the models, and applying ANSYS CFX to analyze the flow fields. Finally, the simulation results are validated using actual flight test data.
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Markin, Shael. "Multiple Simultaneous Specification Attitude Control of a Mini Flying-wing Unmanned Aerial Vehicle." Thesis, 2010. http://hdl.handle.net/1807/25849.
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The Multiple Simultaneous Specification controller design method is an elegant means of designing a single controller to satisfy multiple convex closed loop performance specifications. In this thesis, the method is used to design pitch and roll attitude controllers for a Zagi flying-wing unmanned aerial vehicle from Procerus Technologies. A linear model of the aircraft is developed, in which the lateral and longitudinal motions of the aircraft are decoupled. The controllers are designed for this decoupled state space model. Linear simulations are performed in Simulink, and all performance specifications are satisfied by the closed loop system. Nonlinear, hardware-in-the-loop simulations are carried out using the aircraft, on-board computer, and ground station software. Flight tests are also executed to test the performance of the designed controllers. The closed loop aircraft behaviour is generally as expected, however the desired performance specifications are not strictly met in the nonlinear simulations or in the flight tests.
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Hou, Tzu-Hsuan, and 侯詞軒. "Scale Effect of Wing Span and Flight Kinematic Strategies in Free-Flying Butterflies." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/7k94xr.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
105
The scale of butterflies largely variate among species, and might affect their flight performance intrinsically. In this work, we carry out experimental observations and numerical analysis to investigate how flight performances and flight motions of butterflies correlate with their sizes, and a flight strategy to enhance wing loading of small size butterflies is proposed accordingly. Four different species of Taiwan butterflies with significant differences on wingspan (variating from 44-136 mm) were selected to study experimentally. The motions of butterflies were recorded with high-speed cameras when they were freely flying in an experimental chamber. The images of flight that close to forward flight were selected and analyze with the image processing software (Image J). The experimental results indicate that the wing loading of butterflies positively correlate to their wingspan, and the irregularity of the flight trajectory is not as evident as the previous research (Dudley, 1990). In addition, the flapping frequency and body angle amplitude of the small butterflies are found to be higher than that of large butterflies in our experiments. Numerical models of butterflies in different scales are further created to analyze the size effect quantitatively since various parameters in experiments are combined and are unable to control separately. The butterfly in the simulation translate freely along the vertical and horizontal directions; the flight speeds determined by calculating the aerodynamic force and gravity force. The shape and flight motions of butterflies are considered as the same in each cases, and the mass is manually controlled to find the maximum wing loading of butterflies in specific size. The simulations results show that the wing loading decreases with the wingspan sharply while the shapes and the flight motions are considered as the same. The decreasing rate is more rapid than the trend recorded from experiments, which implies that small butterflies may adjust their flight motions, flapping frequency and body angle amplitude in our observation, to enhance their wing loading in nature. To clarify the effects of these two motions, we further adjust the flapping frequency and rotation amplitude in the simulation model. The results show that both ways effectively improve the wing loading of the butterflies as excepted; moreover, the butterflies are able to achieve higher forward speed with the former motion and are more energy-efficient with the latter motion. Butterflies may alter the flapping frequency or rotation amplitude. Our results provide relations between the size of butterflies and the flight parameters. In an engineering perspective, these relations are especially important for the designing of flight vehicles; for example, determining the total weight of vehicles and power required of the motor. In addition, by comparing the difference between the experimental and simulation results, we proposed a motion control strategy to adjust the flight speed and power consumption of micro aircraft vehicles.