基于无人机汽油发动机高度功率特性研究

Research on Static State Altitude-Power Characteristics of UAV Gasoline Engines

本文研究了无人机(以下简称UAV)使用的两种典型航空非增压、四缸活塞式、二冲程汽油发动机(以下简称测样)。将两种测样安装在移动式测功机上,进行台阶式高原试验,文中着重论述了此类发动机高度-功率适应的计算方法、最大功率转速-高度关系、高度-摩擦功关系、高度-机械效率以及升限。通过试验发现大型航空活塞式发动机高度功率计算公式并不适合各种测样功率计算;此类发动机的最大功率转速点几乎与高度无关;为研讨测样升限提出了测样理论升限及其计算方法。

We present an investigation on two types of small-scale piston gasoline engines（called testing samples or TS） typically mounted on UAV systems that are non-pressure charging,of four-cylinder and two-stroke type.From the high plateau step-like experiments on these two TSs that were installed at a floating dynamometer,the authors propose a calculation method to determine the altitude versus power adaption characteristics,the dependencies between the maximum power speed and altitude,altitude and friction work or mechanical efficiency as well as the flight ceiling.It is demonstrated that calculations from the altitude-power characteristics based on large-scale aerial engines is inapplicable for UAV systems theoretically.In addition,we show that for our UAV engines the maximum power speed point hardly depends on the flying altitude.We facilitate the predictions and calculations on the maximum UAV flight ceilings.