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Number of results: 7
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Abstract

The box wing system is an unconventional way to connect the lifting surfaces that the designers willingly to use in prototypes of new aircrafts. The article present a way to quickly optimize the wing structure of box wing airplane that can be useful during conceptual design. At the beginning, there is presented theory and methods used to code optimization program. Structure analysis is based on FEM beam model, which is sufficient in conceptual design. Optimization is performed using hybrid method, connection of simple iteration and gradient descent methods. Finally, the program is validated by case study.
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Abstract

This paper is an overview of the application potential and design challenges of micro air vehicles (MAVs), defined as small enough to be practical for a single-person transport and use. Four types of MAVs are considered: 1) fixed-wing, 2) rotarywing, 3) ornithopters (bird-like flapping) and 4) entomopters (insect-like flapping). In particular, advantages of a propeller-driven delta wing configuration for type 1 are discussed. Some detail is also given for type 4, the least understood of the four, including a new concept of manoeuvre control for such MAVs. The paper concludes with a brief prognostic of the future of each MAV type.
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Abstract

The normative system of Bogusław Wolniewicz (1927–2017) can be subsumed under three categories: (1) pessimism (fatalism, or ‘tychism’ in Wolniewicz’s terms), (2) moral determinism (‘non-meliorism’), (3) conservatism (‘right-hand orientation’). Ad (1) Wolniewicz was pessimistic in two ways: he believed human life to be tragic (fatalism) and was also convinced that most people are guided by bad instincts (dualism). Ad (2) Wolniewicz believed that moral character was biologically determined and immutable. But his strong position on this subject ignores the classical view of Aristotle or the Stoics for whom moral character (or conscience) was acquired by habit and shaped deliberately. Ad (3) I suggest that a good historical example of conservative tendency was Critias of Athens. His famous fragment of the Sisyphus contains the idea of a supremacy of laws over human passions, and reduces religion to a supportive role with respect to ethics and politics. Wolniewicz’s dualism of right-hand and left-hand orientation encourages me to distinguish between a right-wing and a left-wing perception of value. For a leftist, value is intensity of a chosen feature (progressive value), whereas for a rightist, value is an area of freedom between inacceptable extremities (modular value). On these premises I propose a simple model of axiological conflict between left-wing and right-wing citizens.
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Abstract

The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD) models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.
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Abstract

This paper describes assumptions, goals, methods, results and conclusions related to fuel tank arrangement of a flying wing passenger airplane configuration. A short overview of various fuel tank systems in use today of different types of aircraft is treated as a starting point for designing a fuel tank system to be used on very large passenger airplanes. These systems may be used to move fuel around the aircraft to keep the centre of gravity within acceptable limits, to maintain pitch and lateral balance and stability. With increasing aircraft speed, the centre of lift moves aft, and for trimming the elevator or trimmer must be used thereby increasing aircraft drag. To avoid this, the centre of gravity can be shifted by pumping fuel from forward to aft tanks. The lesson learnt from this is applied to minimise trim drag by moving the fuel along the airplane. Such a task can be done within coming days if we know the minimum drag versus CG position and weight value. The main part of the paper is devoted to wing bending moment distribution. A number of arrangements of fuel in airplane tanks are investigated and a scenario of refuelling – minimising the root bending moments – is presented. These results were obtained under the assumption that aircraft is in long range flight (14 hours), CL is constant and equal to 0.279, Specific Fuel Consumption is also constant and that overall fuel consumption is equal to 20 tons per 1 hour. It was found that the average stress level in wing structure is lower if refuelling starts from fuel tanks located closer to longitudinal plane of symmetry. It can influence the rate of fatigue.
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Abstract

The fossil record of the Antarctic penguins is dated to the late Paleocene of Seymour (Marambio) Island, but the largest sphenisciforms, genera Anthropornis and Palaeeudyptes , originate from the Eocene La Meseta Formation. Here, the most complete large−scale reconstruction of a limb skeleton (a whole wing and a partial hind leg) of a Paleogene Antarctic penguin is reported. All bones are attributable to a single individual identified as Anthropornis sp. The comparative and functional analyses of the material indicate that this bird was most probably well−adapted to land and sea while having a number of intriguing features. The modern−grade carpometacarpal morphology is unique among known Eocene Antarctic species and all but one more northerly taxa.
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Abstract

An important phenomenon of delta wing is the mechanism of vortex core, which indicates the increase in lifting force until the occurrence of the vortex breakdown. The computational fluid dynamics (CFD) is very helpful in visualizing and providing analysis of the detailed data. The use of turbulent models will affect the quality of results in obtaining the vortex breakdown phenomenon. This study used several models of turbulence to capture the occurrence of vortex breakdown and compare it with experiments using water tunnel test facility. The results show that all turbulence models give good results at a low angle of attack (AoA), but at a high AoA the DES model gives the results closest to experimental ones with Cl error value of about 1%. Taking into account the time required and the acceptable level of accuracy, the use of SST and k-omega models is an alternative option for use in the detection of vortex breakdown.
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