The component-level model of variable cycle engine for short take off and vertical landing (STOVL) was built based on modeling method of two-spool-turbofan engine. On the basis of characteristics extrapolation method

the shaft-driven lift fan mathematical model was built. Models of the bypass duct were built using neural network for mapping the bypass total pressure loss. According to the structure and specialty of short takeoff and vertical landing

the static and dynamic co-working equations were set up. With reference to foreign researches' simulation data

the design point was calculated. According to Bevilaqua's method

transient simulation of switching between conventional turbofan and hover turboshaft cycle was carried out. The results of numerical simulation indicate that the error of the mathematical model and foreign research data is less than 1.5%

and the thrust meets hover state requirements. Both models can offer high levels of thrust by increasing the fuel flow a little. The performance variation in simulation is consistent with the specialty of STOVL

so the modeling method of STOVL proposed is feasible.