隐蔽式安装布局涡轴发动机安装损失的飞行试验

为确定轻小型直升机飞行性能评估所需的发动机安装性能损失，对隐蔽式安装布局的涡轴发动机进行了不同直升机飞行姿态的飞行试验。基于试飞数据建立了一套真实飞行条件下涡轴发动机安装损失的计算流程，对比分析了在不同高度和速度下稳定平飞、有/无地效悬停、有/无地效悬停回转、不同高度爬升、不同高度下滑、盘旋、侧后飞等飞行姿态对涡轴发动机安装损失的影响。结果表明：隐蔽式安装布局的涡轴发动机安装损失主要来自进气温升，不同飞行姿态下功率损失为4.3%～20.7%，耗油率相对增量为1.2%～132.7%；功率损失随飞行高度的变化规律不明显，随飞行速度的增大而减小；耗油率相对增量随飞行高度和飞行速度的增大而减小；在近地面的低速飞行姿态下安装损失最小，且受地效影响较小；风速和风向对安装损失的影响较大。

Research on Installation Loss of Turboshaft Engine with Covert Installation Layout

To determine the installation performance loss of turboshaft engines required for the flight performance evaluation of light and small helicopters, flight tests were conducted on turboshaft engine with covert installation layout under different helicopter flight attitudes. Based on test flight data, a set of calculation processes of turboshaft engine installation loss under real flight conditions was established. The effects of flight attitudes such as stable level flight at different altitudes and speeds, IGE/OGE hover, IGE/OGE hover rota? tion, different altitude climb, different altitude glide, circling, and side backward flight on the installation loss of turboshaft engine were compared and analyzed. The results show that the installation loss of turboshaft engine with covert installation layout mainly comes from the inlet temperature rise; the power loss under different flight attitudes is 4.3%-20.7%, and the relative increment of specific fuel consump? tion is 1.2%-132.7%; the power loss does not change obviously with the flight altitude, but decreases with the increase of flight speed; the relative increment of specific flue consumption decreases with the increase of flight altitude and speed; the installation loss is minimized in low-speed flight attitude near the ground, and it is less affected by ground effects; wind speed and direction have a significant impact on installation losses.