A Study of Maximum Range Cruise Flight Strategy

• Main Authors: Yao-Chung, Liu, 劉耀中
• Other Authors: Jeng-Shing Chern
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/56438791074563083713

碩士 === 中華技術學院 === 飛機系統工程研究所 === 97 === Cruise flight is usually the major part of the airplane flight, especially in long distance travel. Therefore, it is always of interesting in looking for the flight strategy to achieve the maximum range. Four strategies are usually considered in cruise flight: constant altitude and constant speed, constant speed and constant angle of attack, constant altitude and constant angle of attack, and optimal cruise flight. This paper investigates the maximum range cruise flight of the three strategies except the optimal cruise 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. The fuel consumption is specified to be 10000 kg. For supersonic flight, a typical light weight high performance airplane with aerodynamic and engine characteristics obtained from a book is used. Fuel weight is specified at 1596 kg. It has been solved that using constant speed and constant angle of attack is the best strategy for B787 with the specified initial and final weights of 155383 kg and 145383 kg, respectively. The best Mach number is 0.83 and the best altitude is 13.3 km. The cruise altitude is in the lower level of the stratosphere and the range obtained is 3602.00 km. As to the high performance supersonic airplane, we obtain the best subsonic range with the cruise flight using constant altitude and constant angle of attack strategy. The best altitude is at 9.9 km and is within the troposphere while the best subsonic speed is at 0.85 Mach. Then, there is another best altitude at 17.7 km within the stratosphere with supersonic speed at 1.46 Mach. The best strategy is the same, i.e., using constant altitude and constant angle of attack cruise flight. From 16967 kg initial weight to 15371 kg final weight, the ranges obtained are 824.43 km and 790.63 km for subsonic cruise and supersonic cruise, respectively. Comparatively the supersonic cruise gives shorter range than the subsonic cruise while the flight time is also shorter. Basically, the differences among the best cruise ranges obtained using the three different strategies are within1.6%. As to the optimal cruise strategy, it will be further studied in the future.