Induced Drag of High-Aspect Ratio Wings

Author(s):  
James Nathman
2015 ◽  
Vol 798 ◽  
pp. 565-570
Author(s):  
Luciano Magno Fragola Barbosa ◽  
Ricardo Luiz Utsch de Freitas Pinto ◽  
Bernardo Oliveira Hargreaves

In this work improvements on the geometry of a high aspect ratio aircraft wing are studied, in order to reduce the wing in-flight deformation, without changing the drag of the aircraft and without increasing the structural weight. For this, from a reference rectangular wing, one new wing with elliptical planform has been defined; and comparative analyses of loads and structural deformation have been made for the wings considered: the original rectangular wing and the new corresponding elliptical wing. The aerodynamic analysis is based on the lifting line approach. A computer routine is made by the authors based on this approach, to obtain both induced drag values and the load distribution of the two wings, the original one and the corresponding elliptical. Based on the loads, spars for the two wings have been defined, and in order to evaluate the vertical displacements in flight, a finite element routine have been used. The main result of this study is the comparison of the deformation of wings considered, subjected to the same load factor, and for the same aircraft mass. The results obtained are encouraging for further developments using the present methodology.


Aerospace ◽  
2020 ◽  
Vol 7 (11) ◽  
pp. 166
Author(s):  
Frederico Afonso ◽  
Mónica Coelho ◽  
José Vale ◽  
Fernando Lau ◽  
Afzal Suleman

Recently, innovative aircraft designs were proposed to improve aerodynamic performance. Examples include high aspect ratio wings to reduce the aerodynamic induced drag to achieve lower fuel consumption. Such solution when combined with a lightweight structure may lead to aeroelastic instabilities such as flutter at lower air speeds compared to more conventional wing designs. Therefore, in order to ensure safe flight operation, it is important to study the aeroelastic behavior of the wing throughout the flight envelope. This can be achieved by either experimental or computational work. Experimental wind tunnel and scaled flight test models need to exhibit similar aeroelastic behavior to the full scale air vehicle. In this paper, three different aeroelastic scaling strategies are formulated and applied to a flexible high aspect-ratio wing. These scaling strategies are first evaluated in terms of their ability to generate reduced models with the intended representations of the aerodynamic, structural and inertial characteristics. Next, they are assessed in terms of their potential in representing the unsteady non-linear aeroelastic behavior in three different flight conditions. The scaled models engineered by exactly scaling down the internal structure suitably represent the intended aeroelastic behavior and allow the performance assessment for the entire flight envelope. However, since both the flight and wind tunnel models are constrained by physical and budgetary limitations, custom built structural models are more likely to be selected. However, the latter ones are less promising to study the entire flight envelope.


Author(s):  
S Rajat Singh ◽  
Amala Raja Rajeswar Gajula ◽  
Praneetha Maccha

The main purpose of a folding wing tip is to allow aerodynamically efficient high aspect ratio wing. To allow a wing tip to move in flight is to alleviate the loads and achieve lower wing weight or enable wing span to maximize. Thus reduces the induced drag and improve fuel efficiency. The folding wing tip may include spring devices in order to provide an additional gust loads alleviation ability in flight. A wing without a winglet produces wingtip vortices which increases drag as the air from the bottom surface of the wing (high pressure) tries to move to the upper surface (low pressure). To avoid this and have less vortices a winglet is used, around which the flow is same on both surfaces. A folding wingtip can be set at an angle of 0° to have maximum cruise performance and aspect ratio. If the wingtip is set in the range of 15°-50° it can increase lift during take-off. This folding wingtip can access any airport in the world because if it is folded at an angle of 90°, it can meet the gate requirements and restrictions of any airport. To study the performance of this mechanism, the wing tip was designed by using CATIA V5 software. The analysis of the wingtip at different angle of attacks was done using ANSYS and XFLR 5 softwares.


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