中文摘要

題 目: 無人連翼機空氣動力特性之風洞實驗研究
研 究 生: 林崇仁
指導教授: 尤芳忞

本研究旨在利用表面油流視流實驗以及量測空氣動力學參數來探討連翼構型飛機之空氣動學特性以及在改進設計上應注重的項目，實驗設計上選用兩個相同構型但在翼形等方面不同之模型進行測試比較。經由油流視流實驗可觀察到本構型之飛機後翼會受前翼誘導之下洗氣流所影響導致有效攻角下降，因而流場分離現象均較前翼延後，而連接前後兩翼之翼端側板作為偏航方向穩定及控制之控制面的能力稍嫌不足，因此在設計的改良上可因需求增加額外垂直方向之控制舵面。由實驗所量測到之空氣動力學參數可發現本構型之飛機在升力係數方面類似於一般單懸臂構型之飛機，由於升力面佔全機重量比例較高，因此相同結構重量下可以提供較大之升力。但在相對於重心位置之俯仰力矩方面則由於前後兩翼升力中心隨攻角改變向後移動的範圍較大，導致機頭下壓之力矩較大，所以在配平時所需之水平控制能力要比較大，因此在後續的改良設計上如何維持適當的重心與升力中心間的相對位置成為設計本構型飛機所需特別注意之重點。

ABSTRACT
Subject：A Wind Tunnel Testing on the Aerodynamics Characteristic of an Unmanned Joined-wing Aircraft
Student：Chun-Jen Lin
Advisor：Fan-Ming Yu

The purposes of this thesis are to investigate the aerodynamics characteristics of a joined-wing aircraft by doing the surface oil flow visualization and of measurement of the aerodynamic parameters. Two models of the experiment are the similar configuration but of different airfoil and geometric outlines. From the results of oil flow visualization, it has been observed that the effective angle of attack of the rear wing on the aircraft is reduced by the downwash introduced by the front wing, thus its flow separation occurs latter than the front wing. The side rudder which connected to the two wings is of less effectiveness as a vertical control surface, and it is considered that an extra vertical fin is required for control purpose. The joined-wing aircraft has the maximum lift coefficient closed to a general aviation configuration, however with its large proportion of wing area, it can offer larger lift under the same structure weight condition. Since the lift centre of the aircraft shifts largely with the change of angles of attack, the pitch moment respect to the center of gravity has a large variation accordingly. In order to trim the aircraft, the design of the position of CG relative to the lift centre is a difficult task on designing this configuration of aircraft.

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