Summary: Among aviation enthusiasts, Northrop Grumman's YF-23 has achieved legendary status due to its performance and the fact that only two prototypes were built before the program was discontinued.

这是中国航天科技集团六院面向商业航天市场研制的大推力火箭发动机“YF-209”。 记者从六院获悉，研制团队在较短时间内突破了发动机多次起动 ...