The return stroke is only about 5% of the difficulty of the power stroke. True jet engines are not required like in helicopters but turbo machinery in air intak

The return stroke is only about 5% of the difficulty of the power stroke. True jet engines are not required like in helicopters but turbo machinery in air intake would vastly increase the lift and maneuverability power. It is the brute force of exploding compressed gasses working against a Venetian valve wing. Contrast to rotary engines?