輕型運動飛機設計參數分析與性能需求估算

輕型運動飛機作為近年來興起的熱門休閒活動，使得輕航機市場蓬勃發展；由於市場發展快速更新產品的週期也逐漸縮短，以及輕航機失事後造成事故較為嚴重，因此適墜性安全也受到重視。此外，複合材料在航空業的應用日益頻繁，因此針對複合材料進行安全性分析及如何對其進行最佳化分析逐漸成為熱門的研究主題。本研究期望找到一套考慮適墜性安全標準之輕航機設計流程。本研究將以威翔航空的CTLS作為研究對象探討輕航機在符合適墜性安全規範之前提下，進行氣動外型與結構之最佳化設計，並比較鋁合金材料與複合材料機身之差別並進行性能需求估算，最後找出此飛機之重要設計參數。本研究使用有限元素軟體ANSYS分別分析鋁合金飛機及複合材料飛機之流場、結構受力及經過最佳化後之撞擊試驗，最後使用AAA飛機設計軟體(Advanced Aircraft Analysis)找出重要飛機設計參數。本研究使用Fluent進行流場模擬計算出阻力值及壓力分佈情形，再以此阻力值作為最佳化的參考；本研究外型最佳化以最小阻力值作為目標函數，結構最佳化在保持結構順從度下進行，以重量移除率作為目標函數，期望找到最佳的氣動外型與符合MIL-STD-1290A的15%壓縮率之結構。接著分別以Single engine類型、Single engine複合材料類型及Homebuilt類型之設計參數進行分析，最終比較三類型之結果與實際飛機之重量差距。最終本研究得到最佳化結果之阻力值約減少24%，並在符合適墜性安全標準下，飛機重量減少約5%，以三類型設計參數進行分析後，發現以Single engine複合材料類型設計參數之分析結果最接近實際飛機，兩者的重量誤差約2.2%，因此能驗證本研究能夠找出此類型飛機之設計參數，並應用於此類型飛機設計能縮短設計時程。

關鍵字

適墜性；外型最佳化；結構最佳化；飛機設計；輕航機

並列摘要

In recent year, flying light sport aircrafts (LSAs hereafter) has become a popular leisure activity, leading to vigorous development of the market of light sport aircraft. Due to the rapid development of the market, product cycle shortening and the serious crashes caused by light aircraft, crashworthiness safety has become a significant issue. Besides, the application of composite materials in the aerospace industry is increasingly growing, so safety analysis and optimization of composite material has become a popular topic. The major aim of this study is to find a design process for light sport aircraft with consideration of crashworthiness safety. With CTLS as research object, the optimization of aerodynamic configuration and structure of the CTLS with crashworthiness safety regulations. Compare the difference between aluminum alloy and composite fuselage, and estimate the performance requirements and then to identify the important parameters. In this study, a commercial package software ANSYS is used to analyze the flow field, structural stresses and impact tests of an aluminum alloy and a composite material respectively. Finally, the AAA software (Advanced Aircraft Analysis) is used to identify fundamental aircraft design parameters. Using Fluent to calculate drag and pressure distributions, and using the drag as a reference for optimization. The objective function for shape optimization is the minimum drag, and structural optimization is the weight removed rate with maintaining structural compliance. It is expected to find the best aerodynamic configuration and conforming with the 15% compression rate structure of MIL-STD-1290A. The design parameters of three types of engines which are Single engine, the Single engine composite and the Homebuilt are analyzed to compare the results of the three types with the weight difference of the actual aircraft. The final optimization of this study results in a drag reduction of about 24% and reduction about 5% in aircraft weight while complying with crashworthiness. After analyzing three types of engines, the result shows that the type of single engine composite is the closest to the actual aircraft, with the error about 2.2%. Therefore, it is possible to verify the design parameters in this study for the type of single engine and applied to this type of aircraft design to shorten the design time.