Variations of oil levels of all tanks in aircraft under gravity feed

Purpose. Past calculations assumed that, under gravity feed, only one tank in aircraft supplies the oil needed for preventing extremely serious accident to happen. Actually, all oil tanks compete for supplying oil. Our method takes into consideration all oil tanks and therefore, we believe, our method is intrinsically superior to traditional methods and is closer to understanding the real seriousness of the oil supply situation. On the basis of network algorithm and time differential method, we established a new calculation model for gravity feed oil of aeroplane fuel system. This model can solve the multiple-branch and transient process simulation problem of gravity feed oil. Finally we give a numerical example for a certain type of aircraft. Fig. 6 and Fig. 7 give respectively the variations of oil level and flow mass per second of each of five oil tanks within a period of 16000 seconds. These variations show preliminarily that our proposed method of calculations is satisfactory.