Final answer:
Clamshell doors are used in aircraft for thrust reversal during landing. They open up and redirect the exhaust gases to create a braking effect, helping the aircraft slow down faster.
Step-by-step explanation:
Clamshell doors are used in aircraft for thrust reversal. When an aircraft is landing, it needs to slow down and come to a stop on the runway. Thrust reversal is a mechanism that helps the aircraft slow down by changing the direction of the exhaust from the engines. The clamshell doors open up, redirecting the exhaust gases forward, which creates a braking effect and helps the aircraft slow down faster.
Reverse thrust is thrust projected in the opposite direction to normal and is used to decelerate an aircraft after landing, in the event of a rejected take-off or, in some limited cases, in flight.
Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's thrust for it to act against the forward travel of the aircraft, providing deceleration.