It is of great significant for prop-fan engine under medium to high Mach number to evaluate the propulsive efficiency of turbofan. turboprop and prop-fan engines. The mathematical model for propulsive efficiency analysis is established by using energy-momentum method based on the model of separate exhaust turbofan engines. and a unified propulsive efficiency analysis method is formed ... https://www.yeehawranches.shop/product-category/skulls/