基于航道3段越障的民用运输机障碍物限制起飞重量计算模型

为研究障碍物对民用运输机最大起飞重量的影响,根据飞机在空中的受力特点及CCAR25-R4的要求,建立了基于航道3段越障的障碍物限制起飞重量的计算模型.模型根据飞机的空中运动方程推导出飞机总航迹和净航迹,再由净航迹的垂直高度与障碍物的高度之间的关系判断飞机是否可以安全越障.计算分析了计算步长、障碍物高度、顺逆风对最大起飞...

Calculation Model of Obstacle Limited Takeoff Weight for Civil Transport Aircraft Based on the Third Segment of the Takeoff Flight Path

In order to study the influence of obstacles on the maximum take-off weight of civil transport aircraft, according to the force characteristics of the aircraft in the air and the requirements of CCAR25-R4, a calculation model of obstacle limited takeoff weight based on the third segment of the take-off flight path is established. According to the motion equations of the aircraft, the gross flight path and the net flight path of the aircraft are derived, and then the relationship between the vertical height of the net flight path and the height of the obstacles is used to judge whether the aircraft can fly over the obstacles safely. The influence of calculation step, height of the obstacles and windspeed on the maximum take-off weight is analyzed. The results show that: the level off height is consistent with the actual situation, and the law of the obstacle limited weight is consistent with the conclusion drawn from the flight manual, and the calculation result is reasonable; the better calculation accuracy and time efficiency can be obtained when the calculation step is 1 s; the obstacle limited weight, the level off point and the level off height are related to the height and position of the obstacles; the influence of downwind or upwind on the obstacle limited weight is linear; at the same wind speed, the weight reduction caused by downwind is greater than the weight increase caused by upwind.; the calculation model can provide theoretical reference for the study of the obstacle limited weight.