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This study explores the design and development of a human-powered aircraft (HPA), leveraging modern engineering techniques, materials science, and advanced CAD/CAM tools. The project addresses key aspects of aircraft design, including the geometry of wings and tail, control and power transmission mechanisms, propeller selection, and material identification to achieve ultra-lightweight construction. The 3DExperience platform facilitated comprehensive model creation, simulation, and production process development, while XFLR5 was employed for aerodynamic profile analysis using the vortex lattice and panel methods. JavaProp aided in evaluating propeller thrust and power requirements. Computational fluid dynamics (CFD) simulations using the SST k-ω turbulence model provided critical insights into flow behavior. The design was found to be theoretically capable of flight, although challenges arose in selecting appropriate software for aerodynamic analysis, leading to the use of XFLR5 for early-stage design and the more advanced 3DExperience platform for final evaluations. Although structural strength analyses were not performed due to the complexity of composite materials, future work in this area could enhance the precision of component selection and aircraft mass estimation. [ABSTRACT FROM AUTHOR]

Most simple ailerons produce adverse yaw. However, with proper aileron placement and wing twist, an aileron can produce proverse or neutral yaw, eliminating the need for aileron-rudder mixing, differential aileron deflection or Frise ailerons. The relationship between wing planform, aileron placement and lift distribution is studied here for a special class of optimal lift distributions that minimise induced drag for a variety of design constraints. It is shown that a wing employing the elliptic lift distribution will always produce adverse yaw, independent of aileron design or operating condition. However, for wings employing other optimal lift distributions, the ailerons can be placed to produce proverse or neutral yaw. A numerical lifting-line algorithm is used to explore the impact of aileron design on a wide range of wing planforms and lift distributions. Results can be used in the early stages of design to correctly place ailerons with respect to desired roll-yaw coupling. [ABSTRACT FROM AUTHOR]

While the aircraft is moving in the opposite direction of the flow in the air, the wind resistance and the moment effect due to this resistance negatively affect the flight performance. In design studies, it is aimed to increase aerodynamic performance by minimizing these two negative factors. In this study, the effect of wing cross section and three-dimensional airfoil on aerodynamic performance is investigated numerically. Within the scope of this study, to reach the intended design, biomimetic design approach was used and new-wing designs were created to mimic the bird species’ wings, which have the highest aerodynamic performance in nature. Based on the literature search for two-dimensional wing section selection, it was seen that the most preferred sections were identified and compared with the wing section of the Cessna 172 aircraft (NACA2412) in flow analysis. In the flow analysis conducted in the XFLR5 program, the aerodynamic performances of the wing sections at Reynolds value and angle of attack were investigated. According to this analysis, the aerodynamic efficiency of the NACA2412 section was higher than that of the other sections. In the three-dimensional flow analysis, biomimetic wing designs and the wing of the Cessna 172 aircraft were examined in the XFLR5 program at a cruising speed and angle of attack. It was observed that the aerodynamic efficiency of the wing design, which is inspired by the albatross, is higher than the other designs. Owing to the flow analysis, the albatross wing design provided 6.26% improvement in the lift coefficient, 15.73% in drag coefficient and 15.16% improvement in the glide ratio compared to the Cessna 172 aircraft wing design. For structural analysis, the pressure values obtained from the flow analysis results were used as the load distribution on the wing. In the designs created using the same material, it was observed that the weight of the wing inspired by the albatross was 34.156% less weight and 50.902% less deformation value obtained compared to Cessna 172 aircraft.

The aim of this study is to investigate the impact of locust-like wing flexibility which is modelled with Mylar and carbon fibre pultruded rods on aerodynamic performance. An in-house 3D Navier Stokes solver coupled with a structure solver has been used to evaluate passive pitching motion and aerodynamic performance. The study has focused on two effects which are variations in the diameter of root and spar distribution. All wings have been analysed for a prescribed flapping motion in a horizontal plane, with a peak-to-peak stroke amplitude of 120°, flapping frequency of 25 Hz, and Reynolds number of 13,500. The flow has been assumed to be laminar, viscous, and incompressible. The diameter of the wing root segment attached to the leading edge has been varied to control the extent of the passive pitching motion. The effect of spar distribution on the aerodynamic performance of the flexible flapping wing has also been investigated. The results revealed that careful selection of wing root parameters and spars distribution can achieve a passive pitch angle with an amplitude of 45° and the highest power economy of 1.26. Moreover, a comparison of the flexible wing with its rigid counterpart suggested that flexible wings modelled with a simple passive pitching mechanism can be an efficient solution for bio-inspired flapping-wing micro aerial vehicles. [ABSTRACT FROM AUTHOR]

While the aircraft is moving in the opposite direction of the flow in the air, the wind resistance and the moment effect due to this resistance negatively affect the flight performance. In design studies, it is aimed to increase aerodynamic performance by minimizing these two negative factors. In this study, the effect of wing cross section and three-dimensional airfoil on aerodynamic performance is investigated numerically. Within the scope of this study, to reach the intended design, biomimetic design approach was used and new-wing designs were created to mimic the bird species’ wings, which have the highest aerodynamic performance in nature. Based on the literature search for two-dimensional wing section selection, it was seen that the most preferred sections were identified and compared with the wing section of the Cessna 172 aircraft (NACA2412) in flow analysis. In the flow analysis conducted in the XFLR5 program, the aerodynamic performances of the wing sections at Reynolds value and angle of attack were investigated. According to this analysis, the aerodynamic efficiency of the NACA2412 section was higher than that of the other sections. In the three-dimensional flow analysis, biomimetic wing designs and the wing of the Cessna 172 aircraft were examined in the XFLR5 program at a cruising speed and angle of attack. It was observed that the aerodynamic efficiency of the wing design, which is inspired by the albatross, is higher than the other designs. Owing to the flow analysis, the albatross wing design provided 6.26% improvement in the lift coefficient, 15.73% in drag coefficient and 15.16% improvement in the glide ratio compared to the Cessna 172 aircraft wing design. For structural analysis, the pressure values obtained from the flow analysis results were used as the load distribution on the wing. In the designs created using the same material, it was observed that the weight of the wing inspired by the albatross was 34.156% less weight and 50.902% less deformation value obtained compared to Cessna 172 aircraft. [ABSTRACT FROM AUTHOR]

With the growing demand for unmanned transportation, the rise of compound drones is imperative. Aerodynamic optimization design plays a significant role in the development cycle of compound drones. Researches were performed on key parameter adaptive screening and design space adaptive updating of surrogate-based aerodynamic optimization techniques. A parametric/spatial adaptive aerodynamic optimization platform was established, which can improve the optimization efficiency and search capability effectively in the process of aerodynamic optimization. A preliminary design scheme of wing for a compound drone was presented, and adaptive aerodynamic optimization was carried out. The lift-to-drag ratios of the optimized wing root and tip airfoils and the resulting optimized wing were all increased by over 5%, with design lift coefficients equaling to 1.0, and the corresponding angles of attack were also reduced by more than 2°. The stall characteristics and the roll control ability of the wing were improved simultaneously.

In the design of flapping-wing micro-size air vehicles capable of hovering, wings serve as the primary source of hovering power, making the analysis of aerodynamics and aerodynamic efficiency crucial. Traditional quasi-steady models treat the wings as single rigid plane, neglecting the deformable characteristics of flexible wings. This paper proposes a multi-plane method that, in conjunction with various design parameters of flexible wings in a two-dimensional plane, analyzes their deformation characteristics under the assumption of multiple planes in three-dimensional space, and describes the deformation of wings during flapping. By combining the quasi-steady aerodynamic model, aerodynamic analysis of the deformed wings can be conducted. The relationship between the slack angle, wing flapping position, and wing deformation are analyzed, along with their effects on aerodynamics and aerodynamic efficiency. Experiments validate the deformation patterns of wings during flapping and compare the simulated aerodynamic forces with measured ones. The results indicate that wing deformation can be accurately described by adjusting the parameters in the multi-plane method and that the aerodynamic analysis using this method closely approximates the average lift results. Additionally, the multi-plane method establishes a connection between wing morphology and aerodynamic forces and efficiency, providing valuable insights for aerodynamic analysis. [ABSTRACT FROM AUTHOR]

Accounting for aeroelastic phenomena, such as flutter, in the conceptual design phase is becoming more important as the trend toward increasing the wing aspect ratio forges ahead. However, this task is computationally expensive, especially when utilizing high-fidelity simulations and numerical optimization. Thus, the development of efficient computational strategies is necessary. With this goal in mind, this work proposes a surrogate-based optimization (SBO) methodology for wing design using a predefined machine learning model. For this purpose, a custom-made Python framework was built based on different open-source codes. The test subject was the classical Goland wing, parameterized to allow for SBO. The process consists of employing a Latin Hypercube Sampling plan and subsequently simulating the resulting wing on SHARPy to generate a dataset. A regression-based machine learning model is then used to build surrogate models for lift and drag coefficients, structural mass, and flutter speed. Finally, after validating the surrogate model, a multi-objective optimization problem aiming to maximize the lift-to-drag ratio and minimize the structural mass is solved through NSGA-II, considering a flutter constraint. This SBO methodology was successfully tested, reaching reductions of three orders of magnitude in the optimization computational time. [ABSTRACT FROM AUTHOR]

This study explores the design and development of a human-powered aircraft (HPA), leveraging modern engineering techniques, materials science, and advanced CAD/CAM tools. The project addresses key aspects of aircraft design, including the geometry of wings and tail, control and power transmission mechanisms, propeller selection, and material identification to achieve ultra-lightweight construction. The 3DExperience platform facilitated comprehensive model creation, simulation, and production process development, while XFLR5 was employed for aerodynamic profile analysis using the vortex lattice and panel methods. JavaProp aided in evaluating propeller thrust and power requirements. Computational fluid dynamics (CFD) simulations using the SST k-ω turbulence model provided critical insights into flow behavior. The design was found to be theoretically capable of flight, although challenges arose in selecting appropriate software for aerodynamic analysis, leading to the use of XFLR5 for early-stage design and the more advanced 3DExperience platform for final evaluations. Although structural strength analyses were not performed due to the complexity of composite materials, future work in this area could enhance the precision of component selection and aircraft mass estimation.

This study focuses on investigating the structural design and stress analysis of a micro aircraft using 3D computer-aided design software. Four distinct wing geometries were designed, each featuring unique wing shapes and dimensions. The maximum stress and deformation tolerances for each wing design were determined through static structural analysis and simulation, identifying potential weak points. The results were analyzed to identify the wing configuration with superior structural performance. The aircraft structure was constructed using balsa wood and polystyrene, while lift factor, air density, velocity, and wing area served as input variables for lift force simulation. A comparative evaluation system based on lift-to-drag ratio, structural strength, stability and control, ease of fabrication, and maneuverability was employed to compare the four designs. The trapezoidal wing design demonstrated the highest design evaluation points, making it the optimal choice among the four. The findings of this study provide valuable insights into stress analysis and structural design of micro airplanes, guiding future investigations and advancements in this domain. Copyright © 2023 Praise Worthy Prize S.r.l. - All rights reserved. [ABSTRACT FROM AUTHOR]

Wing-in-Ground (WIG) effect aircraft are gaining attention for their potential in reducing environmental impact. However, optimising wing planforms based solely on aerodynamics might improve performance while compromising static height stability of WIG aircraft. This study investigates the effects of planar and nonplanar wing planform optimisation for regional transport ground effect aircraft. Three distinct multiobjective wing planform optimisations are explored: planar wing optimisation, nonplanar wing optimisation, and nonplanar wingtip optimisation. These optimisations assess the impact on both aerodynamic efficiency and static height stability characteristics of a wing planform in ground effect, at three different flying altitudes. In extreme ground effect, the Pareto set includes wings with negative spanwise camber, enhancing both cushion sensation and aerodynamic efficiency by effectively utilizing ground effect, thus proving advantageous over planar wing configurations. [ABSTRACT FROM AUTHOR]

Unmanned aerial vehicles (UAVs) have an important place in today's technologies because of the solutions they bring to many critical problems in military and civilian application around the world. One of the important advantages of UAVs in aviation, particularly in the military field, is high observation, reconnaissance and pursuit activities. Fixed-wing UAVs, which have many configurations, stand out with their electric motor models owing to their efficiency and flight cost advantages. However, for reconnaissance and pursuit activities, this must be supported by a low cruise flight speed and high aerodynamic efficiency. In this study, it is aimed to reduce flight speed, to increase flight duration and aerodynamic efficiency by designing new modular wing based on flow analysis. Test flights are performed at different angles of attack and new parameters are determined. As a result of experimental studies, cruise flight speed is significantly reduced and pursuit capabilities of UAV is improved. This development has a positive effect on power consumption of electric motor by reducing current drawn by motor and its RPM value. Due to the reduction of power consumption, flight time increased by 36% and the average current drawn decreased by 45% which makes aerodynamic efficiency to be increased. [ABSTRACT FROM AUTHOR]

In the design of flapping-wing micro-size air vehicles capable of hovering, wings serve as the primary source of hovering power, making the analysis of aerodynamics and aerodynamic efficiency crucial. Traditional quasi-steady models treat the wings as single rigid plane, neglecting the deformable characteristics of flexible wings. This paper proposes a multi-plane method that, in conjunction with various design parameters of flexible wings in a two-dimensional plane, analyzes their deformation characteristics under the assumption of multiple planes in three-dimensional space, and describes the deformation of wings during flapping. By combining the quasi-steady aerodynamic model, aerodynamic analysis of the deformed wings can be conducted. The relationship between the slack angle, wing flapping position, and wing deformation are analyzed, along with their effects on aerodynamics and aerodynamic efficiency. Experiments validate the deformation patterns of wings during flapping and compare the simulated aerodynamic forces with measured ones. The results indicate that wing deformation can be accurately described by adjusting the parameters in the multi-plane method and that the aerodynamic analysis using this method closely approximates the average lift results. Additionally, the multi-plane method establishes a connection between wing morphology and aerodynamic forces and efficiency, providing valuable insights for aerodynamic analysis.

Accounting for aeroelastic phenomena, such as flutter, in the conceptual design phase is becoming more important as the trend toward increasing the wing aspect ratio forges ahead. However, this task is computationally expensive, especially when utilizing high-fidelity simulations and numerical optimization. Thus, the development of efficient computational strategies is necessary. With this goal in mind, this work proposes a surrogate-based optimization (SBO) methodology for wing design using a predefined machine learning model. For this purpose, a custom-made Python framework was built based on different open-source codes. The test subject was the classical Goland wing, parameterized to allow for SBO. The process consists of employing a Latin Hypercube Sampling plan and subsequently simulating the resulting wing on SHARPy to generate a dataset. A regression-based machine learning model is then used to build surrogate models for lift and drag coefficients, structural mass, and flutter speed. Finally, after validating the surrogate model, a multi-objective optimization problem aiming to maximize the lift-to-drag ratio and minimize the structural mass is solved through NSGA-II, considering a flutter constraint. This SBO methodology was successfully tested, reaching reductions of three orders of magnitude in the optimization computational time.

This paper describes the tailless control system design of a flapping-wing micro air vehicle in a four-winged configuration, which can provide high control authority to be stable and agile in flight conditions from hovering to maneuvering flights. The tailless control system consists of variable flapping frequency and wing twist modulation. The variable flapping frequency creates rolling moments through differential vertical force from flapping mechanisms that can be independently driven on the left and right sides. The wing twist modulation changes wing tension, resulting in vertical and horizontal force variations during one flap cycle and generating pitching and yaw moments. We presume that the wing geometry and implementation method of wing-root actuation are related to the control authority of wing twist modulation. Then, the control system's performance is analyzed for various wing geometries and implementation methods, including wing length, leading-edge thickness, camber angle, and vein configuration. Furthermore, the cross-coupling effect is examined for the wing twist modulation, and a control surface interconnect is designed to compensate for the decrease of pitch control authority and adverse rolling moment. The refined wing and control mechanism demonstrated its high control authority without significant loss of vertical force and power efficiency. The flight experiments validated that the control system based on wing twist modulation is suitable for four-winged flapping-wing micro air vehicles, providing sufficient control moment and minimizing the cross-coupling effect., (© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Wing-in-Ground (WIG) effect aircraft are gaining attention for their potential in reducing environmental impact. However, optimising wing planforms based solely on aerodynamics might improve performance while compromising static height stability of WIG aircraft. This study investigates the effects of planar and nonplanar wing planform optimisation for regional transport ground effect aircraft. Three distinct multiobjective wing planform optimisations are explored: planar wing optimisation, nonplanar wing optimisation, and nonplanar wingtip optimisation. These optimisations assess the impact on both aerodynamic efficiency and static height stability characteristics of a wing planform in ground effect, at three different flying altitudes. In extreme ground effect, the Pareto set includes wings with negative spanwise camber, enhancing both cushion sensation and aerodynamic efficiency by effectively utilizing ground effect, thus proving advantageous over planar wing configurations.

The ability of flying continuously over prolonged periods of time has become target of numerous research studies performed in recent years in both the fields of civil aviation and unmanned drones. High altitude platform stations are aircrafts that can operate for an extended period of time at altitudes 17 km above sea level and higher. The aim of this paper is to design and optimize a wing for such platforms and computationally investigate its aerodynamic performance. For that purpose, two-objective genetic algorithm, class shape transformation and panel method were combined and used to define different airfoils with the highest lift-to-drag ratio and maximal lift coefficient. Once the most suitable airfoil was chosen, polyhedral halfwing was modeled and its aerodynamic performances were estimated using the CFD approach. Flow simulations of transitional flow at various angles-of-attack were realized in ANSYS FLUENT and various quantitative and qualitative results are presented, such as aerodynamic coefficient curves and flow visualizations. In the end, daily mission of the aircraft is simulated and its energy requirement is estimated. In order to be able to cruise above Serbia in July, an aircraft weighing 150 kg must accumulate 17 kWh of solar energy per day. [ABSTRACT FROM AUTHOR]

Bird-like flapping-wing aerial vehicles (BFAVs) have attracted significant attention due to their advantages in endurance, range, and load capacity. For a long time, biologists have been studying the enigma of bird flight to understand its mechanism. In contrast, aviation designers focus more on bionic flight systems. This paper presents a comprehensive review of the development of BFAV design. The study aims to provide insights into building a flyable model from the perspective of aviation designers, focusing on the methods in the process of overall design, flapping wing design and drive system design. The review examines the annual progress of flight-capable BFAVs, analyzing changes in prototype size and performance over the years. Additionally, the paper highlights various applications of these vehicles. Furthermore, it discusses the challenges encountered in BFAV design and proposes several possible directions for future research, including perfecting design methods, improving component performance, and promoting practical application. This review will provide essential guidelines and insights for designing BFAVs with higher performance., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Traditional aerodynamic shape optimization methods usually suffer from difficulties in optimization and modeling for high-dimensional aerodynamic optimization problems. To overcome these difficulties, a new high-dimensional aerodynamic shape optimization framework is proposed from the perspectives of geometric domain decomposition for dimensionality reduction and a data-driven model support strategy for changing the role of surrogate model and assisting the optimizer. Geometric domain decomposition uses proper orthogonal decomposition to transform the high-dimensional Class-Shape Function Transformation method into low-dimensional geometric modes to reduce design dimensions for parameterizing the geometric shape, which reduces optimization and modeling difficulties. Also, a data-driven support strategy is proposed to improve the effectiveness and efficiency of the optimizer by learning from historical aerodynamic data; this strategy modifies the role of surrogate model in the optimization framework to assist the optimizer; the surrogate model, serving as an auxiliary role, can reduce the dependence on model accuracy, which overcomes the difficulty of high-dimensional modeling to some extent. We applied the developed framework to transonic drag reduction of wings to validate its performance. The optimization results show that the developed framework converges faster and offers better designs compared to direct optimization and state-of-the-art surrogate-based optimization frameworks for high-dimensional aerodynamic shape optimization. [ABSTRACT FROM AUTHOR]

Composite materials are widely used in aerospace applications due to their good mechanical properties such as low density and good resistance. Due to their versatility it is possible to design different configurations making it difficult to find the optimal option. The objective of this work is to compare different laminates on the wing surface, the advantage of using structural elements such as spars and ribs, also to see the influence on the results of different load simplifications. In the study, the finite element analysis technique is used to find the best characteristics regarding resistance, deformation, and failure modes under the established conditions. The analysis showed that the best load simplification is a decreasing distributed load along the pressure center, the best surface laminate is [45/0/0/45] with carbon fiber cloth with a maximum displacement of 15.27 mm, the spar presented a 29.6% decrease in maximum displacement and the ribs did not represent a significant change in the structural response. [ABSTRACT FROM AUTHOR]

Most modern aircraft employ discrete ailerons for roll control. The induced drag, rolling moment, and yawing moment for an aircraft depend in part on the location and size of the ailerons. In the present study, lifting-line theory is used to formulate theoretical relationships between aileron design and the resulting forces and moments. The theory predicts that the optimum aileron geometry is independent of prescribed lift and rolling moment. A numerical potential flow algorithm is used to evaluate the optimum size and location of ailerons for a wide range of planforms with varying aspect ratio and taper ratio. Results show that the optimum aileron design to minimise induced drag always extends to the wing tip. Impacts to induced drag and yawing moment are also considered, and results can be used to inform initial design and placement of ailerons on future aircraft. Results of this optimisation study are also compared to theoretical optimum results that could be obtained from morphing-wing technology. Results of this comparison can be used to evaluate the potential benefits of using morphing-wing technology rather than traditional discrete ailerons. [ABSTRACT FROM AUTHOR]

Multi-objective topology optimisation problems are often tackled by compromising the cost functions according to the designer's knowledge. Such an approach however has clear limitations and usually requires information which especially at the preliminary design stage could be unavailable. This paper proposes an alternative multi-objective approach for the generation of minimal Pareto sets in combination with density-based topology optimisation. Optimised solutions are generated integrating a recently revised method for a posteriori articulation of preferences with the Method of Moving Asymptotes. The methodology is first tested on an academic two-dimensional structure and eventually employed to optimise a full-scale aerospace structure with the support of the commercial software Altair OptiStructⓇ. For the academic benchmark, the optimised layouts with respect to static and dynamic objectives are visualised on the Pareto frontier and reported with the corresponding density distribution. Results show a progressive and consistent transition between the two extreme single-objective layouts and confirm that the minimum number of evaluations was required to fill the smart Pareto front. The multi-objective strategy is then coupled with Altair OptiStruct and used to optimise a full-scale wing box, with the clear purpose to fill a gap in multi-objective topology optimisation applied to the wing primary structure. The proposed methodology proved that it can generate efficiently non-dominated optimised configurations, at a computational cost that is mainly driven by the model complexity. This strategy is particularly indicated for the preliminary design phase, as it releases the designer from the burden to assign preferences. Furthermore, the ease of integration into a commercial design tool makes it available for industrial applications. [ABSTRACT FROM AUTHOR]

In this paper the flutter behavior of a typical wing is investigated. The study is performed by presented Deferential Quadrature Method (DQM). The aerodynamic part adopted Wagner functions to model subsonic regime. Quasi steady and unsteady aerodynamics are considered to estimate the instability speed of the structure. Based on the presented model, a code is developed, for an arbitrary typical section beam. The obtained results validated the existing methods in the literature. The proposed method provides the advantage of finding the modes of oscillation and other dynamic parameters with less than 0.2% difference.

In this paper, the interpretation of hovering flight for hummingbirds is studied from a hummingbird morphology perspective (muscle and skeleton) including weight distribution, followed by a discussion of hovering aerodynamics. Next, by studying the scale laws, geometry similarity, and statistical analysis on wing parameters, the parametric relation between wing performances and weight is studied, followed by flapping wing micro autonomous drones (FWMADs) design. The efficiency of the designed wings based on the scaling law is verified by flying test. Material difference and methods of design are summarized. Last, the morphology of bird's tails is presented, and then the designs of tails are introduced, followed by discussion of tail performances. The results show that the tail could be predicted to apply to the stability of hovering twin-wing FWMADs. The current studies provide a simple but powerful guideline for biologists and engineers who study the morphology of hummingbirds and design FWMADs.

To unlock the potential of natural laminar flow aircraft wings, novel structural designs are necessary for the wing leading edge and its attachment. Those designs may not impinge on operability and maintenance of the aircraft. This paper presents a leading edge and attachment design for the natural laminar flow environment as well as the testing of this design on a large-scale ground-based demonstrator. The leading edge design is numerically verified by considering operational loads. For operational viability, the replacement of damaged leading edges without alterations to the spare part is desirable. In a series of tests, such interchange trials are made with two ▪ full complexity leading edge segments and the aerodynamic step height at the interface of leading edge and wing cover is assessed in both ground and cruise deformation. The leading edge design and its attachment concept were proven to support natural laminar flow step height requirements even under global part deformations of a multi-material structure under thermal loading both numerically and experimentally. Interchangeability of the leading edge is demonstrated with very low mean variation in step height between different installations. [ABSTRACT FROM AUTHOR]

In the context of reducing the environmental footprint of tomorrow’s aviation, Distributed Electric Propulsion (DEP) has become an increasingly interesting concept. With the strong coupling between disciplines that this technology brings forth, multiple benefits are expected for the overall aircraft design. These interests have been observed not only in the aerodynamic properties of the aircraft but also in the structural design. However, current statistical models used in conceptual design have shown limitations regarding the benefits and challenges coming from these new design trends. As for other methods, they are either not adapted for use in a conceptual design phase or do not cover CS-23 category aircraft. This paper details a semi-analytical methodology compliant with the performance-based certification criteria presented by the European Union Aviation Safety Agency (EASA) to predict the structural mass breakdown of a wing. This makes the method applicable to any aircraft regulated by EASA CS-23. Results have been validated with the conventional twin-engine aircraft Beechcraft 76, the innovative NASA X-57 Maxwell concept using DEP, and the commuter aircraft Beechcraft 1900.

Aerodynamic shape optimization based on computational fluid dynamics has the potential to become more widely used in the industry; however, the optimized shapes are often criticized for not being practical. Techniques seeking more practical results, such as multipoint optimization and geometric constraints, are either ineffective or too time consuming because they require trial and error. We propose a data-driven constraint for the aerodynamic shape optimization of aircraft wings that ensures the overall practicality of the optimum shape, with a focus on achieving a good low-speed performance. The constraint is formulated by extracting the relevant features from an airfoil database via modal analysis, correlation analysis, and Gaussian mixture models. The optimization results demonstrated that this approach addresses the thin leading edge issue that had plagued previous optimization results, and further analysis demonstrated that this data-driven constraint ensures good low-speed off-design performance without sacrificing the transonic on-design performance. The proposed approach can use other airfoil databases and can even be generalized to other shape optimization and engineering design problems. [ABSTRACT FROM AUTHOR]

Over the past several decades, composites have increasingly become the material of choice in modern aircraft structural design. This is primarily due to the high stiffness- and strength-to-weight ratios offered by conventional composites when compared to metals. Unconventional composite designs, such as tow-steered composites, have demonstrated potential for further expanding these advantages. Unlike their conventional composite counterparts, tow-steered composites feature layers with spatially varying fiber orientations. When applied to wing design, tow-steered composites offer an increase in design freedom at the cost of higher design complexity, making them ideal candidates for design optimization. We develop a methodology for the aerostructural design optimization of tow-steered composite wings using high-fidelity physics models. We also quantify the benefits of this new technology by performing a fuel burn minimization for both a tow-steered and a conventional composite wing design. This assessment is done for the undeflected Common Research Model, which is representative of a twin-aisle transport aircraft. We find improvements of up to 2.4% in fuel burn and 24% in wing weight relative to the optimized conventional composite design. We show that this improvement is due to a combination of improved passive aeroelastic tailoring and local strength tailoring in high-stress regions in the tow-steered structure. For a higher-aspect-ratio (13.5) wing design, we find improvements of up to 1.5% and 14% in fuel savings and wing weight, respectively. To better understand the effect of aspect ratio on tow-steered wing design, we perform an optimization study where the aspect ratio is varied between 7.5 and 13.5. We found that there are diminishing returns in the benefit of tow steering as the aspect ratio is increased because less passive load alleviation is possible. [ABSTRACT FROM AUTHOR]

Surrogate models are often used to reduce the cost of design optimization problems that involve computationally costly models, such as computational fluid dynamics simulations. However, the number of evaluations required by surrogate models usually scales poorly with the number of design variables, and there is a need for both better constraint formulations and multimodal function handling. To address this issue, we developed a surrogate-based gradient-free optimization algorithm that can handle cases where the function evaluations are expensive, the computational budget is limited, the functions are multimodal, and the optimization problem includes nonlinear equality or inequality constraints. The proposed algorithm—super efficient global optimization coupled with mixture of experts (SEGOMOE)—can tackle complex constrained design optimization problems through the use of an enrichment strategy based on a mixture of experts coupled with adaptive surrogate models. The performance of this approach was evaluated for analytic constrained and unconstrained problems, as well as for a multimodal aerodynamic shape optimization problem with 17 design variables and an equality constraint. Our results showed that the method is efficient and that the optimum is much less dependent on the starting point than the conventional gradient-based optimization. [ABSTRACT FROM AUTHOR]

Among the high speed crafts to be used as ferries, hydrofoils are considered the best solution to obtain high speeds and to reduce ship motions with the consequent comfort for passengers; in fact as long as the wave heights allow the hydrofoils to fly above the sea level the floating hulls are not effected by the sea conditions. It is important to underline that, in order to achieve the required performances, the construction techniques must be carefully controlled and refined because there are also some structural problems to be faced and solved to obtain a weight reduction. This study shows the results of a complete series of test, in towing tank and at sea, performed by the authors on a new class of hydrofoils designed and built by an Italian line. This research refers, in particular, to the fleet of The Liberty Lines, as they are the most important operators in the world for passenger hydrofoils, with more than 30 units, constantly updating them and recently developing a brand with a new series of semi submerged wings to face the typical defects characterizing this type of naval unit.) where fundamental points have been analyzed such as: the wing hydrodynamic optimization by means of model testing; the structural study of new wing systems and the update of the production processes with new construction techniques, and the improvement of the passengers comfort as for accelerations and vibrations. The tests have demonstrated a significant gain for new projects. [ABSTRACT FROM AUTHOR]

Multidisciplinary design optimization (MDO) has been previously applied to aerostructural wing design problems with great success. Most previous applications involve fine-tuning a well-designed aircraft wing. In this work, we broaden the scope of the optimization problem by exploring the design space of aerostructural wing design optimization. We start with a rectangular wing and optimize the aerodynamic shape and the sizing of the internal structure to achieve minimum fuel burn on a transonic cruise mission. We use a multi-level optimization procedure to decrease computational cost by 40%. We demonstrate that the optimization can transform the rectangular wing into a swept, tapered wing typical of a transonic aircraft. The optimizer converges to the same wing shape when starting from a different initial design. Additionally, we use a separation constraint at a low-speed, high-lift condition to improve the off-design performance of the optimized wing. The separation constraint results in a substantially different wing design with better low-speed performance and only a slight decrease in cruise performance.