Optimization of Airfoils along High-Aspect-Ratio Wing of Long-Endurance Aircraft in Trimmed Flight

2019 ◽  
Vol 32 (6) ◽  
pp. 04019090 ◽  
Author(s):  
Nikolay V. Nikolaev
2012 ◽  
Vol 189 ◽  
pp. 306-311 ◽  
Author(s):  
Qing Guo ◽  
Bi Feng Song

High altitude and long endurance (HALE) vehicle always adopt straight or swept configuration, which leads to the problem that the wings of UAV have high aspect ratio and are very flexible. This kind of flexible wing exhibits large deformation when aerodynamic forces are loaded on them and the structural nonlinearity should be considered. So the dynamic and flutter characteristics will be changed. In the engineering applications, the effects of structural geometric nonlinearities on the air vehicle design are the most concerns of aeroelasticity before a systematic flutter analysis for the air vehicle. because the solution for nonlinear flutter speed based on the CFD-CSD method is complex and time consuming. In this paper, we propose a simple and efficient approach that can analyze the effect of structural geometric nonlinearities on the flutter characteristics of high aspect ratio wing quickly. And a straight wing and a straight-swept wing are analyzed to verify the feasibility and efficiency of the proposed method. It is found that the effect of structural geometric nonlinearities has a strong effect on the flutter characteristic of the straight wing, but is weak on the straight-swept wing. And finally the impact of swept angle on the dynamic and flutter characteristics of straight-swept wing is also discussed.


2010 ◽  
Vol 123-125 ◽  
pp. 105-108
Author(s):  
Myoung Keon Lee ◽  
Chang Min Cho ◽  
Se Yong Jang

HALE (High Altitude Long Endurance) UAVs are aircraft systems for surveillance and reconnaissance for over 25 hours. Most of UAVs consist of fuselage and high aspect ratio wing because of long-endurance flight mission. The structural weight of HALE UAV is one of the most critical design requirements. In addition, the structural stiffness for the high aspect ratio wing is another critical design requirement because the UAV has to keep the minimum clearance between wing tip and ground when the UAV is being towed. For above design requirements, the wing structure of the UAV has been designed by intermediate modulus Gr/Ep composite materials. The goal of this research is to present the optimized design concepts for the composite wing structure of the UAV. Although there are many design parameters for the composite structure of the aircraft, this research is focused on composite structure strength and buckling analysis for the plate type structures, such as cover panel skins and spar webs, which are loaded in in-plane shear and/or compression. This research presents that the wing structural weight can be reduced when the material allowables based on tape laminate are applied instead of unidirectional lamina allowables. For the buckling analysis, this report has a trade off study to find an optimized lay-up design and stacking sequence with 0°, ±45° and 90° plies. This research shows that the critical buckling load is a function of the number of ±45° plies and the position of the ±45° plies through the laminate thickness using a typical Gr/Ep composite tape material. The structural design of the UAV composite wing regarding buckling analysis is more effective when the laminates are stacked up with high percent of ±45° plies and the ±45° plies are located toward outside through the laminate.


Author(s):  
Wojciech Skarka ◽  
Nikodem Ciomperlik

Morphing of aerodynamic surfaces or conformal shape adaptation of aerodynamic surfaces can be used to control aircraft, utilized similarly as in nature, where insects and birds deform their wings to achieve a wide range of flight conditions. Morphing of wings has the potential to bring numerous advantages in flight performance in comparison to a rigid, conventional solution, that utilizes stiff aerodynamic surfaces. Reduction of parasitic drag due to the lack of gaps between the various moveable surfaces is one of them. Even so, a wing whose sections are able to deform independently or conform can better adapt to wide range of flight conditions than a rigid solution, or a solution based on conventional aerodynamic surfaces, such as flaps and ailerons. Additionally, the conformal shape adaptation or morphing of aerodynamic surfaces may lead to a potentially reduced weight and mechanical complexity, which may be achieved by utilizing wing deformations directly in the structure instead of connecting conventional actuation devices to the system. The aim of this paper is to propose a morphic arrangement of a high flexibility and high aspect ratio wing, that could be utilized in High Altitude Long Endurance aircraft, where the efficiency of the design is of utmost importance. A significant reduction of parasitic drag and reduction of weight is a promising basis for pursuing morphic and conformal shape adaptation designs. This paper qualitatively explores the space of morphic arrangements and conformal shape adaptation designs and utilizes inventive approaches to check and identify designs that may be promising. A wing design is proposed, that utilizes morphing of wing and conformal shape adaptation.


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