- 期刊
等高等速飛行最大航程之探討
Investigation of Maximum Range Cruise for Constant Altitude and Speed Flight
摘要
飛機於長途飛行中，巡航飛行佔飛行的最大部份，因此尋求巡航飛行之最大航程顯得特別重要。一般對於巡航飛行的分析，包括下列四種飛行策略：等高度等速率、等高度等攻角、等速率等攻角與最佳化巡航。本文內容為探討在等高度與等速率之巡航飛行情況下，典型的次音速民航機與超音速戰鬥機之最大航程。分析中必須使用到飛機的氣動力與發動機特性，次音速民航機以波音787為分析對象，超音速戰鬥機之特性則取材自參考文獻。次音速民航機之飛行高度一般為對流層，及一部份的同溫層，最大航程之高度通常在對流層內，本文對波音787的分析結果是在同溫層。對超音速之小型高性能飛機而言，其最大飛行高度範圍內可能有兩個最大航程之巡航高度，一個位於對流層，為次音速飛行，另一個位於同溫層，為超音速飛行。超音速飛行一般而言比較耗油，但是具有飛行時間較短的優勢。後續將探討其他飛行策略之最大航程，並進行分析比較。
並列摘要
Cruise flight is usually the major part of the airplane flight, especially in long distance flight. Therefore, it is always of interesting in looking for the flight strategy to achieve the maximum range. Four strategies are typically considered in cruise flight: constant altitude and constant speed, constant altitude and constant angle of attack, constant speed and constant angle of attack, and optimal cruise flight. This paper investigates the maximum range cruise flight of the constant altitude and constant speed strategy. For subsonic flight, we use the Boeing 787 transport as an example. Its aerodynamic and engine characteristics can be obtained from a literature in the public domain. For supersonic flight, a typical light weight high performance airplane with aerodynamic and engine characteristics obtained from a book is used. It has been solved that with the specified initial and final weights, the best Mach number and altitude for Boeing 787 transport are 0.83 and 13.2 km, respectively. The altitude is in the stratosphere. As to the high performance supersonic airplane, there is a best altitude at 9.9 km within the troposphere with subsonic speed at 0.83 Mach. Then, there is another best altitude at 17.7 km within the stratosphere with supersonic speed at 1.42 Mach. Comparatively the supersonic cruise gives shorter range than the subsonic cruise while the flight time is also shorter. We shall further analyze the other cruise strategies in the future work.