工程设计往往具有这样的特点,一年以内的总结可能不符合原来的设想,但是在一系列的设计中你常常会看到通过多年的思考和技术进展所得到的成果,甚至是非常满意的结果。本文重点报导了1981年的这样一个成果——为飞行试验准备的可延伸出口锥(EEC_s)。二十多年前,第一次考虑了采用 EEC_s,使在级间分离后,增加喷管长度,随之加大膨胀比,使火箭发动机的性能提高2—6%。虽然 EEC 的第一次成功的全程、全尺寸试验在1967 Engineering design often has such characteristics, the summary within a year may not be consistent with the original idea, but in a series of design you often see the results obtained through years of thinking and technological progress, and even very satisfied with the results . This article focuses on such a result of 1981 - the Extendable Export Cone (EEC_s) for flight testing. Twenty years ago, for the first time, the use of EEC_s was considered in order to increase the length of the nozzle after separation between the stages and to increase the expansion ratio so that the performance of the rocket engine was increased by 2-6%. Although EEC’s first successful full-time, full-scale trial was in 1967