The operating characteristics of the solid ducted rocket are numerically studied.The results show that the performance of the unchoked ducted rocket (UDR)is superior to that of choked one.The unchoked ducted rocket should work with the high burning-rate-exponent fuel-rich propellant.The aluminum-magnesium fuel-rich propellants for the unchoked ducted rocket with high burning rate,exponent and good flammability limits are developed.Through the connected-pipe tests and numerical analysis,the performance of the unchoked ducted rocket engine is investigated.