Cold Stream Reverse
On the last page we looked at the clamshell bucket . This works fine with smaller engines but it would be impractical to use this system with the large diameter high bypass ratio engines which are common on todays large aircraft. The buckets would have to be extremely large and heavy. Another consideration is that the majority of large aircraft have their engines slung very low to the ground. A clamshell bucket system would run the risk of hitting the ground as it deployed. Because of this, large engines tend to use a cold stream reverse system.

The cold stream reverser is located in the bypass duct of the engine. The bypass air is relatively cold, hence the name of the system. A cold stream system uses blocker doors to pop up into the airflow. As the blocker doors pop up, the rear section of the engine cowling (known as the translating sleeve) slides rearwards and exposes vents which allow the air diverted by the blocked doors to leave the engine in a forward direction. These vents incorporate cascade vanes which do the job of vectoring the airflow forward.
Reproduced with kind permission of Rolls-Royce plc
Blocker doors stowed :-
Airflow rearwards		 Blocker doors deployed
translating sleeve open:-
Airflow forwards
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