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Niu, Zhong-Guo, Xiang-Hui Xu, Jian-Feng Wang, Jia-Li Jiang i Hua Liang. "Experiment on longitudinal aerodynamic characteristics of flying wing model with plasma flow control". Acta Physica Sinica 71, nr 2 (2022): 024702. http://dx.doi.org/10.7498/aps.71.20211425.
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Horizontal tail is eliminated from the flying wing layout for improving the low observable and aerodynamic efficiency, resulting in degrading longitudinal maneuverability and fight stability. The low speed wind tunnel test study of improving the longitudinal aerodynamic characteristics of large aspect ratio flying wing model is carried out by using plasma flow control technology. The flying wing model has a leading-edge sweep angle of 34.5° and an aspect ratio of 5.79. The reasons for deteriorating the static maneuverability and stability of the flying wing model and the mechanism of plasma control of the flow field and longitudinal aerodynamic characteristics are studied by particle image velocimetry (PIV) flow visualization and static force measurement test. The control law of plasma control of the flight maneuverability and stability of the flying wing model is studied through flight test. The fact that the flow separation of the outer wing of the flying wing model occurs earlier than the inner wing and the wing is swept back can result in the forward movement of the aerodynamic center and the deterioration of the longitudinal static stability. The shock disturbance induced by plasma can suppress the flow separation of the suction surface, thereby extending the linear section of the lift curve of the model, preventing the aerodynamic center from moving forward, and improving the longitudinal static stability. When the wind speed is 50 m/s, the plasma control improves the horizontal rudder efficiency at a high angle of attack of the flying wing model, increases the maximum lift coefficient of the model by about 0.1, and postpones the stall angle of attack by more than 4° at different rudder angles. The plasma control allows the flying model to follow the command movement better while flying, increases the flying pitch limit angle from 11.5° to 15.1°, reduces the amplitude of longitudinal disturbance motion by 2°, and reduces the oscillation attenuation time from 15 to 8 s, thereby improving the longitudinal flight maneuverability and stability of the flying wing model. It can be seen that plasma flow control technology has great potential applications in improving the flight quality of flying wing layout.
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Ortega Ancel, Alejandro, Rodney Eastwood, Daniel Vogt, Carter Ithier, Michael Smith, Rob Wood i Mirko Kovač. "Aerodynamic evaluation of wing shape and wing orientation in four butterfly species using numerical simulations and a low-speed wind tunnel, and its implications for the design of flying micro-robots". Interface Focus 7, nr 1 (6.02.2017): 20160087. http://dx.doi.org/10.1098/rsfs.2016.0087.
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Many insects are well adapted to long-distance migration despite the larger energetic costs of flight for small body sizes. To optimize wing design for next-generation flying micro-robots, we analyse butterfly wing shapes and wing orientations at full scale using numerical simulations and in a low-speed wind tunnel at 2, 3.5 and 5 m s −1 . The results indicate that wing orientations which maximize wing span lead to the highest glide performance, with lift to drag ratios up to 6.28, while spreading the fore-wings forward can increase the maximum lift produced and thus improve versatility. We discuss the implications for flying micro-robots and how the results assist in understanding the behaviour of the butterfly species tested.
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Elenin, D. V. "CREATION OF AN EXPERIMENTAL CONTROL BODY (ELEVON) IN THE «FLYING WING» AERODYNAMIC SCHEME". System analysis and logistics 2, nr 28 (1.06.2021): 26–32. http://dx.doi.org/10.31799/2077-5687-2021-2-26-32.
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The article discusses the possibility of creating two schemes of an experimental control body in flight for a UAV of the "Flying Wing" scheme. The concept of creating a real prototype for an experiment in the Solidworks Flow environment and in a wind tunnel with a low incoming flow velocity is presented. Key words: wing, aerodynamic design, UAV, flying wing.
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PRISACARIU, Vasile. "UAV FLYING WING WITH A PHOTOVOLTAIC SYSTEM". Review of the Air Force Academy 17, nr 1 (24.05.2019): 63–70. http://dx.doi.org/10.19062/1842-9238.2019.17.1.8.
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PEPELEA, Dumitru, Marius-Gabriel COJOCARU, Adrian TOADER i Mihai-Leonida NICULESCU. "CFD ANALYSIS FOR UAV OF FLYING WING". SCIENTIFIC RESEARCH AND EDUCATION IN THE AIR FORCE 18, nr 1 (24.06.2016): 171–76. http://dx.doi.org/10.19062/2247-3173.2016.18.1.22.
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Davenport, John. "Wing-loading, stability and morphometric relationships in flying fish (Exocoetidae) from the North-eastern Atlantic". Journal of the Marine Biological Association of the United Kingdom 72, nr 1 (luty 1992): 25–39. http://dx.doi.org/10.1017/s0025315400048761.
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‘Four-winged’ flying fish (in which both pectoral and pelvic fins are hypertrophied) reach greater maximum sizes than ‘two-winged’ forms in which only the pectoral fins are enlarged. Exocoetus obtusirostris shows negatively allometric growth in relation to standard length in terms of body mass (b=2·981), and lateral fin area (b=1·834). In consequence, wing-loading rises in positive allometric fashion with standard length (b=l·236). Pectoral fin length cannot be greater than 78–79% of standard length or swimming will be impaired, so the requirement for increased flying speed resulting from increased wing-loading during growth means that lift:drag ratios have to be improved by relatively narrowed wings and tapered wing tips; features which in turn increase wing-loading. Evidence is presented to show that hypertrophied pelvic fins in four-wingers are required to solve problems of stability in pitch, rather than to decrease wing-loading. The ‘non-flying’ flying fish, Oxyporhamphus micropterus, has very high wing-loadings, but the main reason that it cannot fly is that the centre of gravity of the fish is so far behind the pectoral fins that stalling on take-off would be inevitable. Flying fish possess reasonable quantities of red axial musculature, but no more than are used for cruising in fast-moving pelagic fish such as mackerel; it seems probable that acceleration to take-off speed in flying fish requires use of anaerobic white muscles.
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Shyy, Wei, Chang-kwon Kang, Pakpong Chirarattananon, Sridhar Ravi i Hao Liu. "Aerodynamics, sensing and control of insect-scale flapping-wing flight". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, nr 2186 (luty 2016): 20150712. http://dx.doi.org/10.1098/rspa.2015.0712.
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There are nearly a million known species of flying insects and 13 000 species of flying warm-blooded vertebrates, including mammals, birds and bats. While in flight, their wings not only move forward relative to the air, they also flap up and down, plunge and sweep, so that both lift and thrust can be generated and balanced, accommodate uncertain surrounding environment, with superior flight stability and dynamics with highly varied speeds and missions. As the size of a flyer is reduced, the wing-to-body mass ratio tends to decrease as well. Furthermore, these flyers use integrated system consisting of wings to generate aerodynamic forces, muscles to move the wings, and sensing and control systems to guide and manoeuvre. In this article, recent advances in insect-scale flapping-wing aerodynamics, flexible wing structures, unsteady flight environment, sensing, stability and control are reviewed with perspective offered. In particular, the special features of the low Reynolds number flyers associated with small sizes, thin and light structures, slow flight with comparable wind gust speeds, bioinspired fabrication of wing structures, neuron-based sensing and adaptive control are highlighted.
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Hou, Yu, i Fang Wang. "CPG-Based Movement Control for Bionic Flapping-Wing Mechanism". Applied Mechanics and Materials 226-228 (listopad 2012): 844–49. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.844.
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Flapping-wing flying is a kind of rhythmic movement with symmetry of time and space essentially, and this movement is generated and controlled by Central Pattern Generator (CPG). A 2-DOF flapping mechanism was designed according to the flapping-wing flying principle of insects, and the flapping-wing flying CPG model was constructed by nonlinear oscillators. The system responses were studied, and the influences of the model parameters to the system characteristics were analyzed. Through the engineering simulation of flapping-wing flying control model, the first modal vibration of the system was selected, and the different flying modes of bionic aircraft were realized by adjusting system parameters. This kind of bionic control strategy promoted the movement and control ability of flapping-wing flying, and provided a new method to the generation and control of flapping-wing rhythmic movement.
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Hong, Wei Jiang, i Dong Li Ma. "Influence of Control Coupling Effect on Landing Performance of Flying Wing Aircraft". Applied Mechanics and Materials 829 (marzec 2016): 110–17. http://dx.doi.org/10.4028/www.scientific.net/amm.829.110.
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As flying wing aircraft has no tail and adopts blended-wing-body design, most of flying wing aircrafts are directional unstable. Pitching moment couples seriously with rolling and yawing moment when control surfaces are deflected, bringing insecurity to landing stage. Numerical simulation method and semi-empirical equation estimate method were combined to obtain a high aspect ratio flying wing aircraft’s aerodynamic coefficients. Modeling and simulation of landing stage were established by MATLAB/Simulink. The control coupling effect on lift and drag characteristics and anti-crosswind landing capability was studied. The calculation results show that when the high aspect ratio flying wing aircraft was falling into the deceleration phase, appropriate to increase the opening angle of split drag rudder can reduce the trimming pitching moment deflection of pitch flap, thereby reduce the loss of lift caused by the deflection of pitch flaps. Flying wing aircraft can be rounded out successfully by using the pitch flap gently and steady. Both side-slip method and crabbed method can be applied to the landing of high aspect ratio flying wing aircraft in crosswind, the flying wing aircraft’s anti-crosswind landing capability was weakened by the control coupling effect of split drag rudder and elevon. Sideslip method was recommended in the crosswind landing of flying wing aircraft after calculation and analysis.
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Xie, Liang, Han, Niu, Wei, Su i Tang. "Experimental Study on Plasma Flow Control of Symmetric Flying Wing Based on Two Kinds of Scaling Models". Symmetry 11, nr 10 (9.10.2019): 1261. http://dx.doi.org/10.3390/sym11101261.
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The symmetric flying wing has a simple structure and a high lift-to-drag ratio. Due to its complicated surface design, the flow field flowing through its surface is also complex and variable, and the three-dimensional effect is obvious. In order to verify the effect of microsecond pulse plasma flow control on the symmetric flying wing, two different sizes of scaling models were selected. The discharge energy was analyzed, and the force and moment characteristics of the two flying wings and the particle image velocimetry (PIV) results on their surface flow field were compared to obtain the following conclusions. The microsecond pulse surface dielectric barrier discharge energy density is independent of the actuator length but increases with the actuation voltage. After actuation, the stall angle of attack of the small flying wing is delayed by 4°, the maximum lift coefficient is increased by 30.9%, and the drag coefficient can be reduced by 17.3%. After the large flying wing is actuated, the stall angle of attack is delayed by 4°, the maximum lift coefficient is increased by 15.1%, but the drag coefficient is increased. The test results of PIV in the flow field of different sections indicate that the stall separation on the surface of the symmetric flying wing starts first from the outer side, and then the separation area begins to appear on the inner side as the angle of attack increases.
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Ristroph, Leif, i Stephen Childress. "Stable hovering of a jellyfish-like flying machine". Journal of The Royal Society Interface 11, nr 92 (6.03.2014): 20130992. http://dx.doi.org/10.1098/rsif.2013.0992.
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Ornithopters, or flapping-wing aircraft, offer an alternative to helicopters in achieving manoeuvrability at small scales, although stabilizing such aerial vehicles remains a key challenge. Here, we present a hovering machine that achieves self-righting flight using flapping wings alone, without relying on additional aerodynamic surfaces and without feedback control. We design, construct and test-fly a prototype that opens and closes four wings, resembling the motions of swimming jellyfish more so than any insect or bird. Measurements of lift show the benefits of wing flexing and the importance of selecting a wing size appropriate to the motor. Furthermore, we use high-speed video and motion tracking to show that the body orientation is stable during ascending, forward and hovering flight modes. Our experimental measurements are used to inform an aerodynamic model of stability that reveals the importance of centre-of-mass location and the coupling of body translation and rotation. These results show the promise of flapping-flight strategies beyond those that directly mimic the wing motions of flying animals.
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Xin, Hua, Zhang Ji i Ming Lei. "The Bionic Wing with Winglet in Near Space Aerodynamic Analysis". Applied Mechanics and Materials 644-650 (wrzesień 2014): 1939–42. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.1939.
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With reference to a certain type of flying drones with imitation airfoil design a seagull flat wings and on the basis of its wing tip winglet in this paper. Through to the numerical simulation of two wings, it is concluded that the bionic wing aerodynamic performance is superior to the conventional airfoil wing, after adding wing tip winglet bionic wings effectively reduced the downwash velocity, reduce the induced drag, makes the wing aerodynamic performance is improved. Provide theoretical reference for the design of the uav wing
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O’Callaghan, Felicity, Amir Sarig, Gal Ribak i Fritz-Olaf Lehmann. "Efficiency and Aerodynamic Performance of Bristled Insect Wings Depending on Reynolds Number in Flapping Flight". Fluids 7, nr 2 (10.02.2022): 75. http://dx.doi.org/10.3390/fluids7020075.
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Insect wings are generally constructed from veins and solid membranes. However, in the case of the smallest flying insects, the wing membrane is often replaced by hair-like bristles. In contrast to large insects, it is possible for both bristled and membranous wings to be simultaneously present in small insect species. There is therefore a continuing debate about the advantages and disadvantages of bristled wings for flight. In this study, we experimentally tested bristled robotic wing models on their ability to generate vertical forces and scored aerodynamic efficiency at Reynolds numbers that are typical for flight in miniature insects. The tested wings ranged from a solid membrane to a few bristles. A generic lift-based wing kinematic pattern moved the wings around their root. The results show that the lift coefficients, power coefficients and Froude efficiency decreased with increasing bristle spacing. Skin friction significantly attenuates lift production, which may even result in negative coefficients at elevated bristle spacing and low Reynolds numbers. The experimental data confirm previous findings from numerical simulations. These had suggested that for small insects, flying with bristled instead of membranous wings involved less change in energetic costs than for large insects. In sum, our findings highlight the aerodynamic changes associated with bristled wing designs and are thus significant for assessing the biological fitness and dispersal of flying insects.
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Yang, Xu, Xiao Yi Jin i Xiao Lei Zhou. "Bionic Flapping Wing Flying Robot Flight Mechanism and the Key Technologies". Applied Mechanics and Materials 494-495 (luty 2014): 1046–49. http://dx.doi.org/10.4028/www.scientific.net/amm.494-495.1046.
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The flapping wing flying robot is an imitation of a bird or insect like a new type of flying robots, the paper briefly outlines the current domestic and international research in the field of flapping wing flight mechanism of the progress made flapping wing flying robot design. On this basis, the current course of the study were discussed key technical issues, combined with the current research, flapping wing aircraft for the future development prospects.
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McCracken, Gary F., Kamran Safi, Thomas H. Kunz, Dina K. N. Dechmann, Sharon M. Swartz i Martin Wikelski. "Airplane tracking documents the fastest flight speeds recorded for bats". Royal Society Open Science 3, nr 11 (listopad 2016): 160398. http://dx.doi.org/10.1098/rsos.160398.
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The performance capabilities of flying animals reflect the interplay of biomechanical and physiological constraints and evolutionary innovation. Of the two extant groups of vertebrates that are capable of powered flight, birds are thought to fly more efficiently and faster than bats. However, fast-flying bat species that are adapted for flight in open airspace are similar in wing shape and appear to be similar in flight dynamics to fast-flying birds that exploit the same aerial niche. Here, we investigate flight behaviour in seven free-flying Brazilian free-tailed bats ( Tadarida brasiliensis ) and report that the maximum ground speeds achieved exceed speeds previously documented for any bat. Regional wind modelling indicates that bats adjusted flight speeds in response to winds by flying more slowly as wind support increased and flying faster when confronted with crosswinds, as demonstrated for insects, birds and other bats. Increased frequency of pauses in wing beats at faster speeds suggests that flap-gliding assists the bats' rapid flight. Our results suggest that flight performance in bats has been underappreciated and that functional differences in the flight abilities of birds and bats require re-evaluation.
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Sackey, J., B. T. Sone, K. A. Dompreh i M. Maaza. "Wettability Property In Natural Systems: A Case of Flying Insects". MRS Advances 3, nr 42-43 (2018): 2697–703. http://dx.doi.org/10.1557/adv.2018.367.
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AbstractRecently, scientists have demonstrated that material surfaces in nature that possess special wettability properties are composed of micro- and nanostructures. In this study, we focused on the importance of surface structures in determining the wettability of wings of the flying insect species: Idea malabarica, Lucilia sericata and Chrysomya marginalis. Scanning Electron Microscopy (SEM) analysis indicates the different nano-/micro- structures identified on the wings. Surface roughness which plays a role in influencing the wettability was theoretically estimated from the SEM images. While the spherical liquid water droplets used for testing wettability were observed to float on the surface of the Idea malabarica and Lucilia sericata wings, the surface of the Chrysomya marginalis wing was made completely wet. The super-hydrophobicity of the Idea malabarica wing as compared to the near-hydrophobicity/mild hydrophilicity of the Lucilia sericata wing and the distinct hydrophilicity of the Chrysomya marginilis wing could be attributed to its complicated composition of nano-/microstructures and higher surface roughness value.
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Shevell, Richard S. "Feasibility of the "Flying Wing"". Science 245, nr 4924 (22.09.1989): 1311–12. http://dx.doi.org/10.1126/science.245.4924.1311.d.
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Shevell, R. S. "Feasibility of the "Flying Wing"". Science 245, nr 4924 (22.09.1989): 1311–12. http://dx.doi.org/10.1126/science.245.4924.1311-c.
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Bolsunovsky, A. L., N. P. Buzoverya, B. I. Gurevich, V. E. Denisov, A. I. Dunaevsky, L. M. Shkadov, O. V. Sonin, A. J. Udzhuhu i J. P. Zhurihin. "Flying wing—problems and decisions". Aircraft Design 4, nr 4 (grudzień 2001): 193–219. http://dx.doi.org/10.1016/s1369-8869(01)00005-2.
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Meresman, Yonatan, i Gal Ribak. "Elastic wing deformations mitigate flapping asymmetry during manoeuvres in rose chafers (Protaetia cuprea)". Journal of Experimental Biology 223, nr 24 (9.11.2020): jeb225599. http://dx.doi.org/10.1242/jeb.225599.
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ABSTRACTTo manoeuvre in air, flying animals produce asymmetric flapping between contralateral wings. Unlike the adjustable vertebrate wings, insect wings lack intrinsic musculature, preventing active control over wing shape during flight. However, the wings elastically deform as a result of aerodynamic and inertial forces generated by the flapping motions. How these elastic deformations vary with flapping kinematics and flight performance in free-flying insects is poorly understood. Using high-speed videography, we measured how contralateral wings elastically deform during free-flight manoeuvring in rose chafer beetles (Protaetia cuprea). We found that asymmetric flapping during aerial turns was associated with contralateral differences in chord-wise wing deformations. The highest instantaneous difference in deformation occurred during stroke reversals, resulting from differences in wing rotation timing. Elastic deformation asymmetry was also evident during mid-strokes, where wing compliance increased the angle of attack of both wings, but reduced the asymmetry in the angle of attack between contralateral wings. A biomechanical model revealed that wing compliance can increase the torques generated by each wing, providing higher potential for manoeuvrability, while concomitantly contributing to flight stability by attenuating steering asymmetry. Such stability may be adaptive for insects such as flower chafers that need to perform delicate low-speed landing manoeuvres among vegetation.
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STOICA, Cornel, Dumitru PEPELEA, Mihai NICULESCU i Adrian TOADER. "AERODYNAMIC DESIGN CONSIDERATIONS OF A FLYING WING TYPE UAV". SCIENTIFIC RESEARCH AND EDUCATION IN THE AIR FORCE 19, nr 1 (31.07.2017): 213–20. http://dx.doi.org/10.19062/2247-3173.2017.19.1.24.
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Liu, Yun, Zhi Sheng Jing, Shan Chao Tu, Ming Hao Yu i Guo Wei Qin. "Character Measurement of Flapping-Wing Mechanism". Applied Mechanics and Materials 48-49 (luty 2011): 300–303. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.300.
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The characteristics and the application prospect are analyzed. It is concluded that bionic flapping-wing flying has better lift fore generation efficiency, which is the development trend of aerial vehicles. By the scaling effect analysis on bionic flying mechanism, it is presented that bionic flying could be realized more easily when the sizes are decreased. In this article, the flying mechanism of inset and Aves was studied and the high lift force mechanism of flapping-winging was concluded. In order to make the flapping-flying easier, we design a new type flapping-flying mechanism. A set of flapping-wing move comparatively. It can provide lift force all the time. We test the lift force in the condition of different speed and different frequency. The lift effect is validated on a simple suspend flight device. An experimental platform to measure the aerodynamic force is devised and developed by ourselves. On this equipment, the aerodynamics force of the prototype is test. The result is that enhancing speed or frequency can improve lift force in evidence
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Liu, Guangze, Song Wang i Wenfu Xu. "Flying State Sensing and Estimation Method of Large-Scale Bionic Flapping Wing Flying Robot". Actuators 11, nr 8 (31.07.2022): 213. http://dx.doi.org/10.3390/act11080213.
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A large bionic flapping wing robot has unique advantages in flight efficiency. However, the fluctuation of fuselage centroid during flight makes it difficult for traditional state sensing and estimation methods to provide stable and accurate data. In order to provide stable and accurate positioning and attitude information for a flapping wing robot, this paper proposes a flight state sensing and estimation method integrating multiple sensors. Combined with the motion characteristics of a large flapping wing robot, the autonomous flight, including the whole process of takeoff, cruise and landing, is realized. An explicit complementary filtering algorithm is designed to fuse the data of inertial sensor and magnetometer, which solves the problem of attitude divergence. The Kalman filter algorithm is designed to estimate the spatial position and speed of a flapping wing robot by integrating inertial navigation with GPS (global positioning system) and barometer measurement data. The state sensing and estimation accuracy of the flapping wing robot are improved. Finally, the flying state sensing and estimation method is integrated with the flapping wing robot, and the flight experiments are carried out. The results verify the effectiveness of the proposed method, which can provide a guarantee for the flapping wing robot to achieve autonomous flight beyond the visual range.
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Starr, Christopher K., Robert S. Jacobson, Joan W. Krispyn i Joshua A. Spiers. "Caste and wing loading in a social wasp (Hymenoptera, Vespidae, Dolichovespula maculata)". Journal of Hymenoptera Research 84 (24.08.2021): 381–90. http://dx.doi.org/10.3897/jhr.84.68800.
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Variation in wing design and wing loading according to body weight is well studied across taxa of birds and flying insects. Comparable studies have not been made in the few insects that show substantial size variation within the same phenon of a single species. We examine body measures of adults of the social wasp Dolichovespula maculata (Linnaeus, 1763), with particular attention to the limbs and wing loading. As expected, measures of the length of the legs scales isometrically with overall body weight and size. Against expectation, wing size also scales isometrically with body weight and size. This does not match the general pattern of comparison across species of flying animals, in which larger individuals have relatively larger wings, as a partial compensation for greater wing loading. We suggest that wing size in D. maculata may be constrained by the demands of life in a crowded nest.
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Johansson, L. C., i P. Henningsson. "Butterflies fly using efficient propulsive clap mechanism owing to flexible wings". Journal of The Royal Society Interface 18, nr 174 (styczeń 2021): 20200854. http://dx.doi.org/10.1098/rsif.2020.0854.
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Butterflies look like no other flying animal, with unusually short, broad and large wings relative to their body size. Previous studies have suggested butterflies use several unsteady aerodynamic mechanisms to boost force production with upstroke wing clap being a prominent feature. When the wings clap together at the end of upstroke the air between the wings is pressed out, creating a jet, pushing the animal in the opposite direction. Although viewed, for the last 50 years, as a crucial mechanism in insect flight, quantitative aerodynamic measurements of the clap in freely flying animals are lacking. Using quantitative flow measurements behind freely flying butterflies during take-off and a mechanical clapper, we provide aerodynamic performance estimates for the wing clap. We show that flexible butterfly wings, forming a cupped shape during the upstroke and clap, thrust the butterfly forwards, while the downstroke is used for weight support. We further show that flexible wings dramatically increase the useful impulse (+22%) and efficiency (+28%) of the clap compared to rigid wings. Combined, our results suggest butterflies evolved a highly effective clap, which provides a mechanistic hypothesis for their unique wing morphology. Furthermore, our findings could aid the design of man-made flapping drones, boosting propulsive performance.
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Henningsson, P., F. T. Muijres i A. Hedenström. "Time-resolved vortex wake of a common swift flying over a range of flight speeds". Journal of The Royal Society Interface 8, nr 59 (3.12.2010): 807–16. http://dx.doi.org/10.1098/rsif.2010.0533.
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The wake of a freely flying common swift ( Apus apus L.) is examined in a wind tunnel at three different flight speeds, 5.7, 7.7 and 9.9 m s −1 . The wake of the bird is visualized using high-speed stereo digital particle image velocimetry (DPIV). Wake images are recorded in the transverse plane, perpendicular to the airflow. The wake of a swift has been studied previously using DPIV and recording wake images in the longitudinal plane, parallel to the airflow. The high-speed DPIV system allows for time-resolved wake sampling and the result shows features that were not discovered in the previous study, but there was approximately a 40 per cent vertical force deficit. As the earlier study also revealed, a pair of wingtip vortices are trailing behind the wingtips, but in addition, a pair of tail vortices and a pair of ‘wing root vortices’ are found that appear to originate from the wing/body junction. The existence of wing root vortices suggests that the two wings are not acting as a single wing, but are to some extent aerodynamically detached from each other. It is proposed that this is due to the body disrupting the lift distribution over the wing by generating less lift than the wings.
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Олег Львович Лемко i Євген О. Кушніренко. "AERO DYNAMIC SHAPE OF TRANSPORT AIRCRAFT “FLYING WING” SCHEME WITH HIGH ASPECT RATIO". MECHANICS OF GYROSCOPIC SYSTEMS, nr 27 (6.10.2014): 84–92. http://dx.doi.org/10.20535/0203-377127201438043.
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"Normal" aerodynamic scheme despite the fact that it has become the dominant in global aviation, in terms of aerodynamics is not ideal. To create a lifting force only wing is just necessary. All other elements of aircraft glider - fuselage , horizontal and vertical tail exist only for the crew, passengers and cargo, ensuring the sustainability and management to provide a satisfactory landing characteristics. It became apparent that with the increasing size of the planes becomes possible and appropriate to place all the major part of their weight directly in the wing. This idea was expressed in aerodynamic scheme "flying wing".The purpose of the research is to form aerodynamic look of transport aircraft "flying wing" scheme with high aspect ratio, creating aerodynamic design that provides the greatest rate of return and optimal weight range and flight duration.Objectives of the study are: analysis of scientific sources on establishing LA scheme "flying wing", development of forming methods of the aerodynamic look of transport aircraft scheme "flying wing", based on a synthesis of existing methods for assessing the flight - the technical characteristics of the aircraft, studies and analyzes of theoretical methods of aerodynamic layouts transport aircraft "flying wing" scheme to determine the aerodynamic and flight characteristics. Were used following scientific methods to solve the research problems: 1. Method of forming the aerodynamic characteristics of the freeform aircraft shape in the parameters of similarity and generalized design parameters. 2. Statistical methods for assessing the aerodynamic and performance characteristics. 3. Numerical methods.The practical value of my work: developed method allows you to create aerodynamic layout scheme aircraft "flying wing" of the great extension that allows you to fully realize the benefits of the scheme, developed and reasonable advices on the aircraft aerodynamic look of "flying wing" scheme of high aspect ratio.
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Keidel, Dominic, Giulio Molinari i Paolo Ermanni. "Aero-structural optimization and analysis of a camber-morphing flying wing: Structural and wind tunnel testing". Journal of Intelligent Material Systems and Structures 30, nr 6 (18.02.2019): 908–23. http://dx.doi.org/10.1177/1045389x19828501.
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This article presents the design, optimization and performance assessment of a novel structure-actuation morphing concept for a flying wing, enabling the flight control for straight flight and around the pitch and roll axes. The applied camber-morphing concept utilizes an optimized selectively compliant internal structure, combined with electromechanical actuators to achieve a trailing edge deflection. These deflections lead to variations of the local and global lift, permitting to control the flight of the aircraft. The aero-structural behaviour of the wing is analysed using a coupled three-dimensional aerodynamic and structural simulation tool. An optimization of the planform, aerodynamic shape, internal structure and actuation parameters is performed to attain a longitudinally stable and aerodynamically efficient flying wing. The drag increment caused by morphing is minimized through the numerical optimization, resulting in high aerodynamic efficiency across a range of flight speeds. The stiffness and morphing capabilities of the manufactured wing are characterized experimentally and are compared with the numerical predictions, and the aerodynamic and aeroelastic behaviour of the wing is investigated through wind tunnel tests. The test results indicate the ability of the flying wing to achieve sufficient variations in lift, roll and pitch to control the flight completely through camber morphing.
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Zhang, Haiming, i Zhenzhong Liu. "Design and Research on Flapping Mechanism of Biomimetic Albatross". Journal of Physics: Conference Series 2343, nr 1 (1.09.2022): 012006. http://dx.doi.org/10.1088/1742-6596/2343/1/012006.
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In order to solve the problems of low flying efficiency, poor aerodynamic performance of wing and short flying time distance existing in the research of flapping wing aircraft, a kind of albatron-like flapping wing structure with higher flying efficiency is proposed in this paper. The functions of bird wing flutter, folding and gliding are realized by two degrees of freedom control respectively. First, the flying characteristics of albatross are analyzed and the flying characteristics suitable for albatross are summarized. Propose design requirements for bionic design objectives; The bionic structure design is carried out by referring to the physical structure of wing and the flight motion law, and the key parameters such as the size and angle of connecting rod mechanism are analyzed, calculated and optimized. A clamping mechanism is designed to achieve gear stuck in order to achieve gliding kinetic energy. The three-dimensional model of the flapping wing mechanism is built by solid works, and the motion analysis is carried out by using Motion plug-in. The analysis results of key-point parameters are output, which verifies the movement law and requirements of the mechanism to achieve the design objectives.
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Bourdin, P., A. Gatto i M. I. Friswell. "Performing co-ordinated turns with articulated wing-tips as multi-axis control effectors". Aeronautical Journal 114, nr 1151 (styczeń 2010): 35–47. http://dx.doi.org/10.1017/s0001924000003511.
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Abstract This paper investigates a novel method for the control of aircraft. The concept consists of articulated split wing-tips, independently actuated and mounted on a baseline flying wing. The general philosophy behind the concept was that adequate control of a flying wing about its three axes could be obtained through local modifications of the dihedral angle at the wing-tips, thus providing an alternative to conventional control effectors such as elevons and drag rudders. Preliminary computations with a vortex lattice model and subsequent wind tunnel tests and Navier-Stokes computations demonstrate the viability of the concept for co-ordinated turns, with individual and/or combined wing-tip deflections producing multi-axis, coupled control moments. The multi-axis nature of the generated moments tends to over-actuate the flight control system, leading to some redundancy, which could be exploited to optimise secondary objective functions such as drag or bending moment.
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Jiao, Jing Shan, Xin Hua i Zhang Ji. "Analysis of the Bionic Wing's Aerodynamic Performance". Applied Mechanics and Materials 644-650 (wrzesień 2014): 385–89. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.385.
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According to a certain type of flying in the no imitation gull wing design straight wing with man. Then the bionic wing and conventional airfoil are simulated, and compared the two kinds of wing aerodynamic parameters. The study found, hale no flow man-machine bionic wing design can effectively improve the wing, reduce the upper wing surface flow separation, reduce the lift loss, reduce the pressure drag, improve the lift drag ratio of the wings. In this paper, the simulation results for the design of the UAV wing provides certain reference.
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Johansson, L. Christoffer, Sophia Engel, Emily Baird, Marie Dacke, Florian T. Muijres i Anders Hedenström. "Elytra boost lift, but reduce aerodynamic efficiency in flying beetles". Journal of The Royal Society Interface 9, nr 75 (16.05.2012): 2745–48. http://dx.doi.org/10.1098/rsif.2012.0053.
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Flying insects typically possess two pairs of wings. In beetles, the front pair has evolved into short, hardened structures, the elytra, which protect the second pair of wings and the abdomen. This allows beetles to exploit habitats that would otherwise cause damage to the wings and body. Many beetles fly with the elytra extended, suggesting that they influence aerodynamic performance, but little is known about their role in flight. Using quantitative measurements of the beetle's wake, we show that the presence of the elytra increases vertical force production by approximately 40 per cent, indicating that they contribute to weight support. The wing-elytra combination creates a complex wake compared with previously studied animal wakes. At mid-downstroke, multiple vortices are visible behind each wing. These include a wingtip and an elytron vortex with the same sense of rotation, a body vortex and an additional vortex of the opposite sense of rotation. This latter vortex reflects a negative interaction between the wing and the elytron, resulting in a single wing span efficiency of approximately 0.77 at mid downstroke. This is lower than that found in birds and bats, suggesting that the extra weight support of the elytra comes at the price of reduced efficiency.
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Li, Zhong Jian, i Dong Li Ma. "Control Characteristics Analysis of Split-Drag-Rudder". Applied Mechanics and Materials 472 (styczeń 2014): 185–90. http://dx.doi.org/10.4028/www.scientific.net/amm.472.185.
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Flying wing configuration is a promising candidate for various kinds of unmanned aerial vehicles. However, this kind of configuration eliminates conventional vertical tail and rudder, thus existing severe problems on yawing control. To make the flying wing configuration into practical use, it is especially necessary to gain a deep understanding on the control characteristics of yawing control devices. To the innovative yawing control device: split-drag-rudder, which is most widely used on flying wing configuration, the paper introduced its current research and mechanical feature, then carefully analyzed its yawing control characteristics, three-axis control coupling effect, also influencing regularities on aerodynamics and stabilities. The conclusions can help to provide basis on engineering application for split-drag-rudder, and to some extent, help to solve the yawing control problem for the flying wing configuration.
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Dinh, Bao Anh, Hieu Khanh Ngo i Van Nhu Nguyen. "An efficient low-speed airfoil design optimization process using multi-fidelity analysis for UAV flying wing". Science and Technology Development Journal 19, nr 3 (30.09.2016): 43–52. http://dx.doi.org/10.32508/stdj.v19i3.519.
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This paper proposes an efficient low-speed airfoil selection and design optimization process using multi-fidelity analysis for a long endurance Unmanned Aerial Vehicle (UAV) flying wing. The developed process includes the low speed airfoil database construction, airfoil selection and design optimization steps based on the given design requirements. The multi-fidelity analysis solvers including the panel method and computational fluid dynamics (CFD) are presented to analyze the low speed airfoil aerodynamic characteristics accurately and perform inverse airfoil design optimization effectively without any noticeable turnaround time in the early aircraft design stage. The unconventional flying wing UAV design shows poor reaction in longitudinal stability. However, It has low parasite drag, long endurance, and better performance. The multi-fidelity analysis solvers are validated for the E387 and CAL2463m airfoil compared to the wind tunnel test data. Then, 29 low speed airfoils for flying wing UAV are constructed by using the multi-fidelity solvers. The weighting score method is used to select the appropriate airfoil for the given design requirements. The selected airfoil is used as a baseline for the inverse airfoil design optimization step to refine and obtain the optimal airfoil configuration. The implementation of proposed method is applied for the real flying-wing UAV airfoil design case to demonstrate the effectiveness and feasibility of the proposed method.
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Wang, Yunjie, Yajun Yin, Gangtie Zheng i Hongxiang Yao. "Driving mechanism of dragonfly’s wing flapping pattern for liquid circulation inside wing". Animal Biology 71, nr 1 (1.10.2020): 85–101. http://dx.doi.org/10.1163/15707563-bja10048.
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Abstract Flying animals can inspire practical approaches to a more advanced way of flying. Dragonflies demonstrate a special flapping pattern in which their wings perform torsional movement while flapping, which is different from that of birds. This flapping pattern is referred to as nonsynchronous flapping in this article. We present a hypothesis that nonsynchronous flapping provides a driving force for enhancing the haemolymph circulation inside dragonfly wings. To support this hypothesis, a controlled experiment was designed and conducted with living dragonflies. By observing the liquid motion inside the vein within free flapping wings and restricted wings of living dragonflies, this hypothesis was supported. A mathematical model of the flapping wing was built and numerically studied to further support the function of the nonsynchronous flapping pattern in driving the circulation. With these studies, a theoretical explanation for the mechanism of enhancing the haemolymph circulation by nonsynchronous flapping was provided.
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Liu, Lan, i Zhao Xia He. "Simulation and Experiment for Rigid and Flexible Wings of Flapping-Wings Microrobots". Advanced Materials Research 97-101 (marzec 2010): 4513–16. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.4513.
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In this paper, an insect-based flapping-wing flying microrobot was built which can successfully fly in the sky. The unsteady aerodynamics associated with this microrobot was studied by using the method of computational fluid dynamics (CFD). On the basis of numerical simulation, the Fluid-Structure coupling mechanics for flexible flapping-wings were studied and discussed. According to the practically developed flapping-wing microrobot, a 2-D simulation model for flexible flapping-wings was established. Fluid-Structure coupling deformation and the effects of this model on the aero dynamic performance were analyzed, which have offered a theoretical basis for design of the aircraft with flexible flapping-wing. In order to verify the results of numerical simulation, aerodynamic performance tests have been conducted for the rigid and flexible flapping-wings in a low turbulence and low Reynolds number wind tunnel.
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Dimitriadis, G., J. D. Gardiner, P. G. Tickle, J. Codd i R. L. Nudds. "Experimental and numerical study of the flight of geese". Aeronautical Journal 119, nr 1217 (lipiec 2015): 803–32. http://dx.doi.org/10.1017/s0001924000010939.
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AbstractThe flight of barnacle geese at airspeeds representing high-speed migrating flight is investigated using experiments and simulations. The experimental part of the work involved the filming of three barnacle geese (Branta Leucopsis) flying at different airspeeds in a wind tunnel. The video footage was analysed in order to extract the wing kinematics. Additional information, such as wing geometry and camber was obtained from a 3D scan of a dried wing. An unsteady vortex lattice method was used to simulate the aerodynamics of the measured flapping motion. The simulations were used in order to successfully reproduce the measured body motion and thus obtain estimates of the aerodynamic forces acting on the wings. It was found that the mean of the wing pitch angle variation with time has the most significant effect on lift while the difference in the durations of the upstroke and downstroke has the major effect on thrust. The power consumed by the aerodynamic forces was also estimated; it was found that increases in aerodynamic power correspond very closely to climbing motion and vice versa. Root-mean-square values of the power range from 100W to 240W. Finally, it was observed that tandem flying can be very expensive for the trailing bird.
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Pan, Yalin, i Jun Huang. "Influences of airfoil profile on lateral-directional stability of aircraft with flying wing layout". Aircraft Engineering and Aerospace Technology 91, nr 7 (8.07.2019): 1011–17. http://dx.doi.org/10.1108/aeat-04-2018-0119.
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Purpose The purpose of this study is to analyze influence of airfoil profile on lateral-directional flying quality of flying wing aircraft. The lateral-directional stability is always insufficient for aircraft with the layout due to the absence of vertical stabilizer. A flying wing aircraft with double-swept wing is used as research object in the paper. Design/methodology/approach The 3D model is established for the aircraft with flying wing layout, and parametric modeling is carried out for airfoil mean camber line of the aircraft to analyze lateral-directional stability of the aircraft with different camber line parameters. To increase computational efficiency, vortex lattice method is adopted to calculate aerodynamic coefficients and aerodynamic derivatives of the aircraft. Findings It is found from the research results that roll mode and spiral mode have a little effect on lateral-directional stability of the aircraft but Dutch roll mode is the critical factor affecting flying quality level of such aircraft. Even though changes of airfoil mean line parameters can greatly change assessment parameters of aircraft lateral-directional flying quality, that is kind of change cannot have a fundamental impact on level of flying quality of the aircraft. In case flat shape parameters are determined, the airfoil profile has a limited impact on Dutch roll mode. Originality/value Influences of airfoil profile on lateral-directional flying quality of aircraft with double-swept flying wing layout are revealed in the thesis and some important rules and characteristics are also summarized to lay a theoretical basis for design of airfoil and flight control system of aircraft with the layout.
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Hawkes, Elliot W., i David Lentink. "Fruit fly scale robots can hover longer with flapping wings than with spinning wings". Journal of The Royal Society Interface 13, nr 123 (październik 2016): 20160730. http://dx.doi.org/10.1098/rsif.2016.0730.
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Hovering flies generate exceptionally high lift, because their wings generate a stable leading edge vortex. Micro flying robots with a similar wing design can generate similar high lift by either flapping or spinning their wings. While it requires less power to spin a wing, the overall efficiency depends also on the actuator system driving the wing. Here, we present the first holistic analysis to calculate how long a fly-inspired micro robot can hover with flapping versus spinning wings across scales. We integrate aerodynamic data with data-driven scaling laws for actuator, electronics and mechanism performance from fruit fly to hummingbird scales. Our analysis finds that spinning wings driven by rotary actuators are superior for robots with wingspans similar to hummingbirds, yet flapping wings driven by oscillatory actuators are superior at fruit fly scale. This crossover is driven by the reduction in performance of rotary compared with oscillatory actuators at smaller scale. Our calculations emphasize that a systems-level analysis is essential for trading-off flapping versus spinning wings for micro flying robots.
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Liu, Xiaodong, Peiliang Zhang, Guanghong He, Yongen Wang i Xudong Yang. "Multi-objective aerodynamic optimization of flying-wing configuration based on adjoint method". Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 39, nr 4 (sierpień 2021): 753–60. http://dx.doi.org/10.1051/jnwpu/20213940753.
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In order to solve the multi-objective multi-constraint design in aerodynamic design of flying wing, the aerodynamic optimization design based on the adjoint method is studied. In terms of the principle of the adjoint equation, the boundary conditions and the gradient equations are derived. The Navier-Stokes equations and adjoint aerodynamic optimization design method are adopted, the optimization design of the transonic drag reduction for the two different aspect ratio of the flying wing configurations is carried out. The results of the optimization design are as follows: Under the condition of satisfying the aerodynamic and geometric constraints, the transonic shock resistance of the flying wing is weakened to a great extent, which proves that the developed method has high optimization efficiency and good optimization effect in the multi-objective multi-constraint aerodynamic design of the flying wing.
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Hainsworth, F. Reed. "Wing movements and positioning for aerodynamic benefit by Canada geese flying in formation". Canadian Journal of Zoology 67, nr 3 (1.03.1989): 585–89. http://dx.doi.org/10.1139/z89-084.
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Wing tip spacing (the distance between wing tips of adjacent birds at maximum span, perpendicular to the flight path), depth (distance between adjacent birds along the flight path), wing beat frequencies, and extreme relative wing positions were measured for Canada geese (Branta canadensis) flying in V formations to test for use of variation in trailing wing tip vortex positions produced by wing movements. Use of vertical vortex position variation requires similarity in wing beat frequency. An average of only 48% of 73 birds in eight formations had frequencies similar to those of the bird ahead during migratory flight (difference ≤ 0.1 beat/s). Birds whose wing beat frequency was similar to that of the bird ahead differed in depth based on whether wings were in or out of phase. Use of horizontal vortex position variation involves variation in wing tip spacing with depth, which was observed, but variation was high and median wing tip spacing was less for birds with similar wing beat frequencies to the bird ahead in only two of eight formations. Induced power saving may be limited by unpredictable moves of birds ahead and by ability to track trailing vortex positions.
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Muijres, Florian T., Melissa S. Bowlin, L. Christoffer Johansson i Anders Hedenström. "Vortex wake, downwash distribution, aerodynamic performance and wingbeat kinematics in slow-flying pied flycatchers". Journal of The Royal Society Interface 9, nr 67 (15.06.2011): 292–303. http://dx.doi.org/10.1098/rsif.2011.0238.
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Many small passerines regularly fly slowly when catching prey, flying in cluttered environments or landing on a perch or nest. While flying slowly, passerines generate most of the flight forces during the downstroke, and have a ‘feathered upstroke’ during which they make their wing inactive by retracting it close to the body and by spreading the primary wing feathers. How this flight mode relates aerodynamically to the cruising flight and so-called ‘normal hovering’ as used in hummingbirds is not yet known. Here, we present time-resolved fluid dynamics data in combination with wingbeat kinematics data for three pied flycatchers flying across a range of speeds from near hovering to their calculated minimum power speed. Flycatchers are adapted to low speed flight, which they habitually use when catching insects on the wing. From the wake dynamics data, we constructed average wingbeat wakes and determined the time-resolved flight forces, the time-resolved downwash distributions and the resulting lift-to-drag ratios, span efficiencies and flap efficiencies. During the downstroke, slow-flying flycatchers generate a single-vortex loop wake, which is much more similar to that generated by birds at cruising flight speeds than it is to the double loop vortex wake in hovering hummingbirds. This wake structure results in a relatively high downwash behind the body, which can be explained by the relatively active tail in flycatchers. As a result of this, slow-flying flycatchers have a span efficiency which is similar to that of the birds in cruising flight and which can be assumed to be higher than in hovering hummingbirds. During the upstroke, the wings of slowly flying flycatchers generated no significant forces, but the body–tail configuration added 23 per cent to weight support. This is strikingly similar to the 25 per cent weight support generated by the wing upstroke in hovering hummingbirds. Thus, for slow-flying passerines, the upstroke cannot be regarded as inactive, and the tail may be of importance for flight efficiency and possibly manoeuvrability.
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Vasile, PRISACARIU. "CFD Analysis of UAV Flying Wing". INCAS BULLETIN 8, nr 3 (8.09.2016): 65–72. http://dx.doi.org/10.13111/2066-8201.2016.8.3.6.
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Rodríguez-Cortés, H., i A. Arias-Montaño. "Robust geometric sizing of a small flying wing planform based on evolutionary algorithms". Aeronautical Journal 116, nr 1176 (luty 2012): 175–88. http://dx.doi.org/10.1017/s0001924000006680.
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Abstract In this paper a geometric sizing method for a small electric powered flying wing is proposed. The geometric sizing method aims to reduce the effects of variations in the power plant characteristics on endurance. This results in a single-objective design optimisation problem where the sensitivity to power plant characteristics of the endurance equation is minimised, constrained to Reynolds number, wing load, wing taper ratio, aircraft size and wing sweep angle. As a result, geometric characteristics of the flying wing such as span, tip chord and root chord are obtained. Flying wing aerodynamic characteristics are obtained by means of an inviscid fluid flow analysis program of the type low-order panel methods, known as CMARC. The optimisation problem involves a non convex function so that it is necessary to rely on heuristic programming methods. In particular an Evolutionary Algorithm based on differential evolution is considered.
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Zhu, Jiachen, Zhiwei Shi, Quanbing Sun, Jie Chen, Yizhang Dong i Junquan Fu. "Yaw control of a flying-wing unmanned aerial vehicle based on reverse jet control". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, nr 6 (7.02.2020): 1237–55. http://dx.doi.org/10.1177/0954410019899513.
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Due to its layout, there are difficulties in realizing heading attitude control of a flying-wing unmanned aerial vehicle. In this paper, a reverse jet control scheme has been designed: (1) to replace the resistance rudders that are used for the yaw control of a conventional flying-wing unmanned aerial vehicle, (2) to assist and optimize heading attitude control, eliminate the adverse effects of the control surface and enhance stealth performance, and (3) to promote the use of rudderless flight for flying-wing unmanned aerial vehicles. To explore the control mechanism and the flow field of the reverse jet scheme, three-dimensional numerical simulations and low-speed wind tunnel experiments were carried out. First, the numerical simulations evaluated the feasibility and effectiveness of the reverse jet control scheme and explored and optimized the excitation parameters for the scheme. Then the forces were measured in a wind tunnel, and particle image velocimetry experiments were carried out. A reverse jet actuator was independently designed to verify the results of the numerical simulation. The results show that when the reverse jet excitation is applied, the jet obstructs the mainstream, destroys the flow field at the excitation position, and causes early separation of the flow, which increases the pressure drag on the wings and produces a control effect. The control effect mainly depends on the separation degree of the leeward surface. The larger the jet momentum coefficient is, the smaller the jet angle is, and the closer the excitation position is to the leading edge, the greater the separation degree of the leeward surface is, the better the heading attitude control effect is.
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Walker, Simon M., Adrian L. R. Thomas i Graham K. Taylor. "Deformable wing kinematics in free-flying hoverflies". Journal of The Royal Society Interface 7, nr 42 (15.05.2009): 131–42. http://dx.doi.org/10.1098/rsif.2009.0120.
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Here, we present a detailed analysis of the deforming wing kinematics of free-flying hoverflies ( Eristalis tenax , Linnaeus) during hovering flight. We used four high-speed digital video cameras to reconstruct the motion of approximately 22 points on each wing using photogrammetric techniques. While the root-flapping motion of the wing is similar in both the downstroke and upstroke, and is well modelled as a simple harmonic motion, other wing kinematic parameters show substantial variation between the downstroke and upstroke. Whereas the magnitude of the angle of incidence varies considerably within and between different hoverflies, the twist distribution along the wing is highly stereotyped. The angle of incidence and camber both show a recoil effect as they change abruptly at stroke reversal. Pronation occurs consistently after stroke reversal, which is perhaps surprising, because this has been found to reduce lift production in modelling studies. We find that the alula, a hinged flap near the base of the wing, operates in two discrete states: either in plane with the wing, or flipped approximately normal to it. We hypothesize that the alula may be acting as a flow-control device.
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Jie, Chen, i LIN Jianxin. "Fault tolerant control of uav with wing layout based on control allocation". E3S Web of Conferences 233 (2021): 04008. http://dx.doi.org/10.1051/e3sconf/202123304008.
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As the flying wing layout unmanned aerial vehicle (uav) extensive research and task environment increasingly complex, Yu Feiyi layout unmanned aerial vehicle (uav) for fault tolerant control gradually become the main technical means of the flight control, using the established mathematical model of the flying wing uav longitudinal layout setting the actuator failure effect, is in the nature of adaptive control allocation fault-tolerant algorithm is given, and MATLAB/simulink simulation is carried out for uav longitudinal motion, realize the rapid and stable, the control command and response to complete the nonlinear fault-tolerant control of flying wing uavs.
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Phan, Hoang Vu, Steven Aurecianus, Taesam Kang i Hoon Cheol Park. "KUBeetle-S: An insect-like, tailless, hover-capable robot that can fly with a low-torque control mechanism". International Journal of Micro Air Vehicles 11 (styczeń 2019): 175682931986137. http://dx.doi.org/10.1177/1756829319861371.
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For an insect-like tailless flying robot, flapping wings should be able to produce control force as well as flight force to keep the robot staying airborne. This capability requires an active control mechanism, which should be integrated with lightweight microcontrol actuators that can produce sufficient control torques to stabilize the robot due to its inherent instability. In this work, we propose a control mechanism integrated in a hover-capable, two-winged, flapping-wing, 16.4 g flying robot (KUBeetle-S) that can simultaneously change the wing stroke-plane and wing twist. Tilting the stroke plane causes changes in the direction of average thrust and the wing twist distribution to produce control torques for pitch and roll. For yaw (heading change), root spars of left and right wings are adjusted asymmetrically to change the wing twist during flapping motion, resulting in yaw torque generation. Changes in wing kinematics were validated by measuring wing kinematics using three synchronized high-speed cameras. We then performed a series of experiments using a six-axis force/torque load cell to evaluate the effectiveness of the control mechanism via torque generation. We prototyped the robot by integrating the control mechanism with sub-micro servos as control actuators and flight control board. Free flight tests were finally conducted to verify the possibility of attitude control.
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Zhou, Hong Xia, i Bin Liu. "Characteristics Analysis and Optimization of Flying-Wing Vehicle Structure". Advanced Materials Research 1077 (grudzień 2014): 177–84. http://dx.doi.org/10.4028/www.scientific.net/amr.1077.177.
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To study structural characteristics of flying-wing vehicle, static and dynamic model of half wing span, static and dynamic model of all wing span, optimization model were established. Based on associated static test and ground resonance test data, these models were modified to implement static, dynamic and optimization analysis. Results demonstrated that structural bending and torsional deformations are mainly at outer wing surface. Torsion at inner wing is positive, while torsion at outer wing is negative. Total spar axial force along the wing span increases gradually from inner wing to outer wing and then decreases gradually after reaching the inner-outer wing interface. After axial force is transmitted to the inner wing, it is going to concentrate at the rear spar obviously. Structural bending rigidity and torsional rigidity satisfy requirements of both static force and flutter, without flutter problem of main structural mode. Viewed from the optimization size, ±45° and 0° skin at inner-outer wing turn thickens significantly. This can increase structural bending and torsional rigidity, which is good for satisfying multiple constraints comprehensively.
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Palmer, Colin, i Gareth Dyke. "Constraints on the wing morphology of pterosaurs". Proceedings of the Royal Society B: Biological Sciences 279, nr 1731 (28.09.2011): 1218–24. http://dx.doi.org/10.1098/rspb.2011.1529.
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Animals that fly must be able to do so over a huge range of aerodynamic conditions, determined by weather, wind speed and the nature of their environment. No single parameter can be used to determine—let alone measure—optimum flight performance as it relates to wing shape. Reconstructing the wings of the extinct pterosaurs has therefore proved especially problematic: these Mesozoic flying reptiles had a soft-tissue membranous flight surface that is rarely preserved in the fossil record. Here, we review basic mechanical and aerodynamic constraints that influenced the wing shape of pterosaurs, and, building on this, present a series of theoretical modelling results. These results allow us to predict the most likely wing shapes that could have been employed by these ancient reptiles, and further show that a combination of anterior sweep and a reflexed proximal wing section provides an aerodynamically balanced and efficient theoretical pterosaur wing shape, with clear benefits for their flight stability.