With an increase in forward speed, the engine thrust.

• A. Increases
• B. Decreases
• C. Remains constant
• D. Decreases slightly but recover due to ram effect.

Answer: (D)

As forward speed increases, the air hitting the engine experiences a ram effect, raising the stagnation pressure at the inlet. That higher inlet pressure boosts air density entering the compressor, increasing the mass flow and the pressure ratio the engine can develop for the same throttle setting. This extra energy in the stream increases the jet momentum and helps offset the natural reduction in thrust that comes from the smaller velocity difference between the exhaust and the surrounding air as the aircraft moves faster. The result is a small overall decrease in thrust with speed, but that drop is partially recovered by the ram effect’s boost to inlet conditions. Hence thrust decreases slightly but recovers due to ram effect.