Lower ambient temperature has what effect on mass flow and thrust?

• A. higher mass flow and higher thrust.
• B. lower mass flow and lower thrust.
• C. mass flow unchanged but higher thrust.
• D. higher mass flow but lower thrust.

Answer: (A)

Lower ambient temperature makes the air denser. Since mass flow into the engine is the air density times the intake volume flow, denser air means more mass enters per second. More mass accelerated and expelled as exhaust increases the momentum change, giving higher thrust. So cooler air leads to both higher mass flow and higher thrust.