Multidisciplinary wing design of a light long endurance UAV

2019 ◽  
Vol 91 (6) ◽  
pp. 905-914 ◽  
Author(s):  
Wojciech Grendysa
Keyword(s):  
Wind Tunnel ◽  
Aircraft Design ◽  
Structure Design ◽  
Unmanned Aircraft ◽  
Geometric Parameters ◽  
Flight Mechanics ◽  
Geometrical Parameters ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Long Endurance

Purpose The purpose of this paper is finding the optimal geometric parameters and developing of a method for optimizing a light unmanned aerial vehicle (UAV) wing, maximizing, at the same time, its endurance with the assumed parameters of aircraft mission. Design/methodology/approach The research is based on the experience gained by the author’s contribution to the project of building medium-altitude, long-endurance class, light UAV called “Samonit”. The author was responsible for the structure design, wind tunnel tests and flight tests of the “Samonit” aircraft. Based on the experience, the author was able to develop an optimization process considering various disciplines involved in the whole aircraft design topics such as aerodynamics, flight mechanics, structural stiffness and weight, aircraft stability and maneuverability. The presented methodology has a multidisciplinary nature, as in the process of optimization both aerodynamic aspects and the influence of wing geometric parameters on the wing structure and weight and the aircraft payload were taken into account. The optimal wing configuration was obtained using the genetic algorithms. Findings As a result, a set of wing geometrical parameters has been obtained that allowed for achieving twice as long endurance as compared with the initial one. Practical implications Using the methodology presented in the paper, an aircraft designer can easily find the optimum wing configuration of a designed aircraft, satisfying the mission requirements in a best way. Originality/value An original procedure has been developed, based on the actual design, wind tunnel tests and numerical calculations of “Samonit” aircraft, enabling the determination of optimum wing configuration for a small unmanned aircraft.

Using additive manufactured parametric models for wind tunnel test-based aerodynamic shape optimization

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hyoung Seog Chung ◽  
Seung Pil Kim ◽  
Younseok Choi
Keyword(s):  
Wind Tunnel ◽  
Shape Optimization ◽  
Design Process ◽  
Wind Tunnel Test ◽  
Aircraft Design ◽  
Parametric Models ◽  
Shape Design ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Aerodynamic Shape

Purpose The purpose of this paper is to propose a new approach of using additively manufactured parametric models in the wind tunnel test-based aerodynamic shape optimization (ASO) framework and to present its applicability test results obtained from a realistic aircraft design problem. Design/methodology/approach For aircraft shape optimization, the following three methodologies were used. First, as a validation study, the possibility of using rapid prototyping (RP) model in the wind tunnel test was verified. Second, through the wind tunnel test-based ASO, the application and feasibility of the real fighter aircraft shape optimization were verified. A generic fighter configuration is parameterized to generate various test models using additive manufacturing. Wind tunnel tests are conducted to measure their stability criteria in high angle of attack (AOA). Finally, a computational fluid dynamics (CFD) study was performed and analysis procedures, costs and results compared to the wind tunnel test were compared and reviewed. Findings RP technology can significantly reduce the time and cost of generating parametric wind tunnel models and can open up new possibilities for wind tunnel tests to be used in the rigorous aerodynamic design loop. There was a slight difference between the results of the RP model and the metallic model because of rigidity and surface roughness. However, the tendency of the aerodynamic characteristics was very similarly predictable. Although there are limitations to obtaining precise aerodynamic data, it is a suitable method to be applied to comparative studies on various shapes with large geo-metric changes in the early phase of design. The CFD analysis indicates that the wind tunnel-based ASO using the RP model shows the efficiency corresponding to the CFD shape optimization. Research limitations/implications The RP parametric models may have various assembly error sources and rigidity problems. The proposed methodology may not be suitable for collecting the accurate aerodynamic database of a final design; rather, the methodology is more suitable to screen out many configurations having fairly large shape variation in the early stage of the design process. Practical implications The wind tunnel test-based ASO can replace or supplement CFD-based ASO. In areas where CFD accuracy is low, such as high AOA flight characteristics, RP model wind tunnel-based ASO can be a research method that can secure both efficiency and accuracy advantages, providing ten times more effective in terms of cost and time. The wind tunnel test is used to obtain aerodynamic data at the final stage of shape design. It can be extended to a comparative study of several shapes in the early design phase. This procedure can be applied for both industrial level and educational aircraft design activities. Originality/value This study is the application to be applied as a parametric study on the whole aircraft, rather than using the RP model applying a simple partial control surface or configuration change of a part of the wing. The possibility of using the RP model was confirmed by comparing and verifying each other in a medium-sized wind tunnel using a relatively large RP model and a metallic model. It was verified that it can be applied in the shape design process, not the shape verification in the traditional design procedure, and a comparison with the CFD method was also performed. With further development and validation efforts, the new design framework may become an industrial standard for future aircraft development.

Aerodynamic and structural design for the development of a MALE UAV

2018 ◽  
Vol 90 (7) ◽  
pp. 1077-1087 ◽  
Author(s):  
Pericles Panagiotou ◽  
Efstratios Giannakis ◽  
Georgios Savaidis ◽  
Kyros Yakinthos
Keyword(s):  
Structural Design ◽  
Design Procedure ◽  
Unmanned Aircraft ◽  
Content Type ◽  
Parameterized Design ◽  
Detail Design ◽  
Aerial Vehicle ◽  
Structural Parts ◽  
Long Endurance ◽  
Structural Aspects

Purpose The purpose of this paper is to present the preliminary design of a medium altitude long endurance (MALE) unmanned aerial vehicle (UAV), focusing on the interaction between the aerodynamic and the structural design studies. Design/methodology/approach The classic layout theory was used, adjusted for the needs of unmanned aircraft, including aerodynamic calculations, presizing methods and CFD, to estimate key aerodynamic and stability coefficients. Considering the structural aspects, a combination of layout, finite element methods and custom parameterized design tools were used, allowing automatic reshapes of the skin and the internal structural parts, which are mainly made of composite materials. Interaction loops were defined between the aforementioned studies to optimize the performance of the aerial vehicle, maximize the aerodynamic efficiency and reduce the structural weight. Findings The complete design procedure of a UAV is shown, starting from the final stages of conceptual design, up to the point where the detail design and mechanical drawings initiated. Practical implications This paper presents a complete view of a design study of a MALE UAV, which was successfully constructed and flight-tested. Originality/value This study presents a complete, synergetic approach between the configuration layout, aerodynamic and structural aspects of a MALE UAV.

Decision tree classifiers for unmanned aircraft configuration selection

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
João Antônio Dantas de Jesus Ferreira ◽  
Ney Rafael Secco
Keyword(s):  
Decision Tree ◽  
Aircraft Design ◽  
Classification Problem ◽  
Unmanned Aircraft ◽  
Requirements Traceability ◽  
Content Type ◽  
Configuration Selection ◽  
Incomplete Databases ◽  
Engine Type ◽  
Selection Of

Purpose This paper aims to investigate the possibility of lowering the time taken during the aircraft design for unmanned aerial vehicles by using machine learning (ML) for the configuration selection phase. In this work, a database of unmanned aircraft is compiled and is proposed that decision tree classifiers (DTC) can understand the relations between mission and operational requirements and the resulting aircraft configuration. Design/methodology/approach This paper presents a ML-based approach to configuration selection of unmanned aircraft. Multiple DTC are built to predict the overall configuration. The classifiers are trained with a database of 118 unmanned aircraft with 57 characteristics, 47 of which are inputs for the classification problem, and 10 are the desired outputs, such as wing configuration or engine type. Findings This paper shows that DTC can be used for the configuration selection of unmanned aircraft with reasonable accuracy, understanding the connections between the different mission requirements and the culminating configuration. The framework is also capable of dealing with incomplete databases, maximizing the available knowledge. Originality/value This paper increases the computational usage for the aircraft design while retaining requirements’ traceability and increasing decision awareness.

Solar UAV design framework for a HALE flight

2019 ◽  
Vol 91 (7) ◽  
pp. 927-937
Author(s):  
Hoyon Hwang ◽  
Jaeyoung Cha ◽  
Jon Ahn
Keyword(s):  
User Interfaces ◽  
Minimum Weight ◽  
Lift Coefficient ◽  
Aircraft Design ◽  
Design Framework ◽  
Night Time ◽  
Simple Method ◽  
Content Type ◽  
Aerial Vehicle ◽  
Long Endurance

Purpose The purpose of this paper is to present the development of an optimal design framework for high altitude long endurance solar unmanned aerial vehicle. The proposed solar aircraft design framework provides a simple method to design solar aircraft for users of all levels of experience. Design/methodology/approach This design framework consists of algorithms and user interfaces for the design of experiments, optimization and mission analysis that includes aerodynamics, performance, solar energy, weight and flight distances. Findings The proposed sizing method produces the optimal solar aircraft that yields the minimum weight and satisfies the constraints such as the power balance, the night time energy balance and the lift coefficient limit. Research limitations/implications The design conditions for the sizing process are given in terms of mission altitudes, flight dates, flight latitudes/longitudes and design factors for the aircraft configuration. Practical implications The framework environment is light and easily accessible as it is implemented using open programs without the use of any expensive commercial tools or in-house programs. In addition, this study presents a sizing method for solar aircraft as traditional sizing methods fail to reflect their unique features. Social implications Solar aircraft can be used in place of a satellite and introduce many advantages. The solar aircraft is much cheaper than the conventional satellite, which costs approximately $200-300m. It operates at a closer altitude to the ground and allows for a better visual inspection. It also provides greater flexibility of missions and covers a wider range of applications. Originality/value This study presents the implementation of a function that yields optimized flight performance under the given mission conditions, such as climb, cruise and descent for a solar aircraft.

An experimental parametric study on planar sheared wings tip devices for low-to-moderate aspect ratio wings

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lourelay Moreira dos Santos ◽  
Guilherme Ferreira Gomes ◽  
Rogerio F. Coimbra
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Parametric Study ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Sweep Angle ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Wing Tips ◽  
Wing Tip

Purpose The purpose of this study is to investigate the aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips. Design/methodology/approach In this work, wind tunnel tests were made to study the influence in aerodynamic characteristics over a typical low-to-moderate-aspect-ratio wing of a general aviation aircraft, equipped with sheared – swept and tapered planar – wing tips. An experimental parametric study of different wing tips was tested. Variations in its leading and trailing edge sweep angle as well as variations in wing tip taper ratio were considered. Sheared wing tips modify the flow pattern in the outboard region of the wing producing a vortex flow at the wing tip leading edge, enhancing lift at high angles of attack. Findings The induced drag is responsible for nearly 50% of aircraft total drag and can be reduced through modifications to the wing tip. Some wing tip models present complex geometries and many of them present benefits in particular flight conditions. Results have demonstrated that sweeping the wing tip leading edge between 60 and 65 degrees offers an increment in wing aerodynamic efficiency, especially at high lift conditions. However, results have demonstrated that moderate wing tip taper ratio (0.50) has better aerodynamic benefits than highly tapered wing tips (from 0.25 to 0.15), even with little less wing tip leading edge sweep angle (from 57 to 62 degrees). The moderate wing tip taper ratio (0.50) offers more wing area and wing span than the wings with highly tapered wing tips, for the same aspect ratio wing. Originality/value Although many studies have been reported on the aerodynamics of wing tips, most of them presented complex non-planar geometries and were developed for cruise flight in high subsonic regime (low lift coefficient). In this work, an exploration and parametric study through wind tunnel tests were made, to evaluate the influence in aerodynamic characteristics of a low-to-moderate-aspect-ratio, tapered, untwisted, unswept wing, equipped of sheared wing tips (wing tips highly swept and tapered).

Wind tunnel tests of the inverted joined wing and a comparison with CFD results

2018 ◽  
Vol 90 (4) ◽  
pp. 586-601
Author(s):  
Cezary Galinski ◽  
Grzegorz Krysztofiak ◽  
Marek Miller ◽  
Pawel Ruchala ◽  
Marek Kalski ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Control Surface ◽  
Dual Use ◽  
Wind Tunnel Tests ◽  
Content Type ◽  
Flying Qualities ◽  
Computational Fluid Dynamics Cfd ◽  
Joined Wing ◽  
Surface Deflections

Purpose The purpose of this paper is to present the methodology and approach adapted to conduct a wind tunnel experiment on the inverted joined-wing airplane flying model together with the results obtained. Design/methodology/approach General assumptions underlying the dual-use model design are presented in this paper. The model was supposed to be used for both wind tunnel tests and flight tests that significantly drive its size and internal structure. Wind tunnel tests results compared with the outcome of computational fluid dynamics (CFD) were used to assess airplane flying qualities before the maiden flight was performed. Findings Extensive data about the aerodynamic characteristics of the airplane were collected. Clean configurations in symmetric and asymmetric cases and also configurations with various control surface deflections were tested. Practical implications The data obtained experimentally made it possible to predict the performance and stability properties of the unconventional airplane and to draw conclusions on improvements in further designs of this configuration. Originality/value The airplane described in this paper differs from frequently analyzed joined-wing configurations, as it boasts a front lifting surface attached at the top of the fuselage, whereas the aft one is attached at the bottom. The testing technique involving the application of a dual-use model is also innovative.

scholarly journals Characteristics of Wind Load on Spatial Structures with Typical Shapes due to Aerodynamic Geometrical Parameters and Terrain Type

2018 ◽  
Vol 2018 ◽  
pp. 1-18 ◽  
Author(s):  
Yi Zhou ◽  
Yuanqi Li ◽  
Yingying Zhang ◽  
Akihito Yoshida
Keyword(s):  
Wind Tunnel ◽  
Pressure Distribution ◽  
Strong Dependence ◽  
Wind Load ◽  
Wind Pressure ◽  
Geometrical Parameters ◽  
Spatial Structures ◽  
Wind Tunnel Tests ◽  
Terrain Type ◽  
Design Optimum

The characteristics of wind load on large-span roofs are complicated by their unique geometrical configurations and strong dependence on aerodynamic geometrical parameters and terrain type. However, there is rarely comprehensive research for characteristics of wind load on spatial structures due to aerodynamic geometrical parameters of roofs and terrain type. In this study, first, the effects of geometrical parameters of roofs and terrain type on the wind pressure distribution based on the data obtained from the existing wind tunnel tests were summarized. Then, the wind loads of full-scale structures were predicted by CFD, and the efficiency of numerical results was further verified by the available wind tunnel tests on spatial structures. Finally, with comparative analyses of the wind pressure distribution of the roofs predicted by CFD under different cases, the effects of shape ratios, especially rise-span ratio, height-span ratio, length-span ratio, and so on, and terrain type on the wind pressure field of typical spatial structures were presented. It can be beneficial to wind-resistant design of structures and can be provided as reference for aerodynamic design optimum of span spatial structures.

scholarly journals Constraint Equations of Physical and Geometrical Parameters of an Arbitrary Branched Hydraulic System of the General Form

2019 ◽  
pp. 58-66
Author(s):  
A.I. Demidov ◽  
I.O. Bobarika ◽  
I.N. Gusev
Keyword(s):  
Power Systems ◽  
Hydraulic System ◽  
Flow Distribution ◽  
Aircraft Design ◽  
Geometric Parameters ◽  
Physical Parameters ◽  
Geometrical Parameters ◽  
Internal Parameters ◽  
Output Characteristics

The development trends of aviation technology impose stringent requirements for the quality of aircraft design in general and its onboard power systems in particular. The article considers an arbitrary branched hydraulic system of the aircraft. With known output characteristics of the hydraulic system, i.e. the function that it must perform, the internal parameters of the system that provide efficient flow distribution required for the calculated operation of the mechanisms are determined. The problem of obtaining a system of equations of the general form linking the physical parameters of the hydraulic system, such as supply power, pressure in consumers and flow rate in all functional subsystems, with the geometric parameters of the pipelines and consumers of the system is solved by an analytical method. The equations in the resulting system are considered in the space of physical parameters. As the geometric parameters of the elements are not specified in an explicit form, it allows the authors to obtain the only unique solution for an arbitrary number of pipelines and consumers, excluding an iterative process. Besides, the final equations clearly determine the most effective mode of operation of the power supply.

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