The flight performance of hypersonic cruise vehicles（HCVs）,a competitive focus of international aerospace technologies in the 21st century,can be measured by a ratio of the initial boost mass to the generalized payload.A coupling frame to analyze the performance was established in Ref.[1].Under the frame,two important effects,namely the centrifugal force and glide distance,have been further taken into account in this article.It was shown quantitatively that for a given distance,the first important factor to affect the flight performance of HCVs is the cruise speed,the second is the lift-to-drag ratio,and the third is the specific impulse of the cruise engine.As a flight distance increases,the performance of a rocket-based HCV,greatly improved due to the centrifugal force and glide distance taken into account,is significantly superior to the classical minimum-energy trajectory from short-middle to long range.A hypersonic air-breathing ramjet,though its specific impulse much higher than that of a rocket engine,is not so good as the latter in terms of the cruise speed range and lift-to-drag ratio.It is concluded that rocket-based HCVs flying at the optimal speed are a very competitive choice at the current stage. 更多
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