Abstract: So far there is not an effective and clear method to calculate the delay time of a command system, which more often than not is determined by experience and experiments. To provide reference for a command system design of an aircraft, reduce experiment time, and save expenses, a method of risk coefficients is put forward which calculates the delay time of a command system by comparing the risk coefficients. Simulation results show that “00” ejection is the crucial condition for calculating the delay time, while the other conditions are insignificant. Effective trajectory diffusion cannot be attained on the delay time alone; a track separation system is necessary. Through an optimal combination with the track separation rocket, the command system delay time of this aircraft is 125 s and 135 s, and the total impulse of the rocket is 110 N·s, and the work time is 50 ms. In addition, the risk of burn of crew members by late ejection is very small, which agrees with the result of the experiment. Comparison with the relevant data shows that this method can provide effective reference for command system design.

Key words: multicrew member ejection, seats, command system, track separation system, risk coefficient, delay time