At approximately what airspeed can the turboprop engine deliver more thrust than the turbojet engine of the same gas turbine design?

The turboprop engine typically provides more efficient thrust at lower speeds compared to turbojet engines, making it an ideal choice for subsonic flight. Turbojet engines, on the other hand, excel at higher speeds, with their efficient thrust production increasing significantly as airspeed approaches and exceeds Mach 1.

In the context of the chosen correct answer, a turboprop engine generates more thrust than a turbojet primarily at subsonic speeds, and its efficiency starts to drop off as speeds increase towards and beyond Mach 1. Therefore, as airspeed approaches Mach 1, the turbojet’s thrust characteristics improve significantly, allowing it to outperform the turboprop engine.

As a result, the comparison clearly shows that the turboprop engine can only deliver more thrust than the turbojet engine at subsonic speeds, which is not reflected in the selected answer. Hence, the correct assessment of when a turboprop outperforms a turbojet is actually within the subsonic range, before reaching Mach 1.