An experimental study was performed at Mach 3.85 wind tunnel about back pressure and self-starting characteristics for sidewall-compression inlet with variable internal contraction ratio.The results show that

the internal contraction ratio has effects on back pressure characteristics of sidewall-compression inlet;the inlet with internal contraction ratio 1.19 can withstand a maximum back pressure of 23.42 times static pressure;the inlet with internal contraction ratio 1.24 can withstand a maximum back pressure of 26.44 times static pressure;The sidewall-compression inlet can realize self-starting by moving cowl backwards.