Ram effects in jet engines are described as leading to what thrust behavior with increasing airspeed?

• A. Permanent thrust decrease
• B. No change in thrust
• C. Partial thrust recovery
• D. Total recovery of thrust as speed increases

Answer: (D)

Ram effect is the increase in engine inlet pressure as the aircraft speeds up. As airspeed rises, the air is effectively “rammed” into the intake, boosting stagnation pressure at the compressor face. That higher inlet pressure raises the engine’s overall pressure ratio and mass flow, which makes the jet exhaust faster relative to the aircraft. The result is more thrust and, as speed continues to increase, this ram rise offsets losses that might exist at lower speeds, leading to a near-complete recovery of thrust with increasing speed. So the thrust behavior described is that thrust essentially recovers completely as speed goes up.