起飞转弯爬升梯度损失分析

起飞转弯爬升会降低飞机的爬升能力,影响起飞安全,为了保障越障安全,需要详细确定梯度损失。通过动力学模型推导出转弯爬升时的梯度损失计算公式,揭示了试飞数据内在原理,分析了固定坡度角转弯、固定转弯半径转弯的梯度损失影响因素和转弯对起飞限重的影响。利用最小二乘法拟合了极曲线参数,计算了某机型的梯度损失数据,与试飞数据相比,计算结果平均偏差不超过0.73%,标准差不超过1.54%。可用于飞机离场程序设计、飞行性能的快速计算以及四维航迹预测。

Climb Gradient Decrement Analysis in Turning Departure

Because of climb ability reducing in turning, it is necessary to determine an accurate gradient decrement for the safety of obstacles clearance in takeoff. Climb decrement calculate expression in turning was deduced by dynamic model and inherent principle in flight test data was revealed. Influence factors of weight limitation and climb decrement in fixed bank angle turn and fixed radius turn were analyzed. The polar curve parameters were fitted by least squares and a climb decrement was calculated. Compared with flight test data, average deviation is less than 0.73% and the standard deviation is not more than 1.54%. It is to say that it can be used in one engine out departure design, flight performance fast calculation in airborne software and 4D- trajectory predication.