Does anyone know the purpose of the nozzles at the end of CF6 engines on MD-11? They don't appear on PW powered MD-11 nor do they appear on CF6-powered 747 or 767. They reappear on the A300/310/330 that are powered by CF6.
Also they appear on all engines available on the 777. I have wondered what determines when these exhaust nozzles are used or whether they inside the cowling or actually stick out.