Engine Auto-Deceleration in Reverse Based on Groundspeed

[zerograv]

Originally Posted by 320busboy

not sure why they did it on the 220 as it’s a fan reverser.

Did I got this right ? On the 220 the fan actually reverses sense of rotation to generate reverse thrust ? Like after touchdown it comes briefly to a full stop from its normal sense of rotation, then it goes into reverse motion ?

[eckhard]

Er, no. It means that only the fan airflow (cold stream) is blocked and reversed. The core airflow (hot stream) still comes out the back and provides forward thrust. Fan airflow is much more powerful than core airflow so the overall effect is reverse thrust. Sometimes called a “cascade type” reverser.

in a “target type” reverser, the entire exhaust stream is blocked and reversed, both fan and core.