Thrust reversers are more effective at ______ speeds.

Thrust reversers are more effective at ______ speeds.

• A. Very high
• B. Medium
• C. High
• D. Low

Answer: (C)

Thrust reversers are most effective at higher speeds because the braking they provide comes from deflecting engine exhaust forward and creating a retarding force on the airplane. The amount of drag generated depends on how much air mass is being redirected and how fast that air is moving relative to the aircraft. When you’re moving quickly, a larger volume of air is in motion and the momentum change caused by reversing that flow is greater, giving more deceleration. As speed drops during the landing rollout, less air is being accelerated and the momentum exchange is smaller, so the reverser’s braking effect diminishes. So, their usefulness is greatest while the aircraft is still moving fast after touchdown.

Thrust reversers are most effective at higher speeds because the braking they provide comes from deflecting engine exhaust forward and creating a retarding force on the airplane. The amount of drag generated depends on how much air mass is being redirected and how fast that air is moving relative to the aircraft. When you’re moving quickly, a larger volume of air is in motion and the momentum change caused by reversing that flow is greater, giving more deceleration. As speed drops during the landing rollout, less air is being accelerated and the momentum exchange is smaller, so the reverser’s braking effect diminishes. So, their usefulness is greatest while the aircraft is still moving fast after touchdown.