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).

中文翻译：

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中低宽高比机翼的平面剪力翼尖装置的实验参数研究

目的

这项研究的目的是研究配备了剪力式翼尖的低至中等长宽比，锥形，不扭曲，不后掠的机翼的空气动力学特性。

设计/方法/方法

在这项工作中，进行了风洞测试，以研究空气动力学特性对配备了剪切-后掠和锥形平面-翼尖的一般航空飞机的典型的低-中-高-纵横比机翼的影响。测试了不同翼尖的实验参数研究。考虑了其前掠角和后掠角的变化以及翼尖锥度比的变化。剪断的机翼尖端会改变机翼外侧区域的流动模式，从而在机翼尖端前缘产生涡流，从而在高攻角下增强升力。

发现

感应阻力约占飞机总阻力的50％，可通过对翼尖进行修改来减小。一些机翼尖端模型呈现出复杂的几何形状，其中许多在特定的飞行条件下都具有优势。结果表明，在60至65度之间扫掠机翼尖端前缘可提高机翼的空气动力效率，特别是在高升力条件下。然而，结果表明，适中的翼尖锥度比（0.50）比高度渐缩的翼尖（从0.25到0.15）具有更好的空气动力学优势，即使翼尖前缘后掠角较小（从57度到62度）也是如此。对于相同纵横比的机翼，适中的机翼尖端锥度比（0.50）比具有高度渐缩的机翼尖端的机翼提供更大的机翼面积和机翼跨度。

创意/价值

尽管已经报道了许多有关翼尖空气动力学的研究，但大多数研究都提出了复杂的非平面几何形状，并且被开发用于高亚音速状态（低升力系数）的巡航飞行。在这项工作中，通过风洞试验进行了探索和参数研究，以评估配备有剪切式翼尖（翼尖）的中低纵横比，锥形，不扭曲，不扫掠的机翼对空气动力特性的影响。高度扫过并呈锥形）。