DC-8 ejector
Once a common sight at large airports, the distinctive DC-8 ejector/reverser mechanisms are seldom seen or thought about today, other than possibly by modelers.  From left to right we see the back end of the JT4 engine, the sound suppressor, and the ejector (extended in this view.) The ejector was said to increase thrust by some small amount by drawing in more air at the front and mixing it with the hot core exhaust stream, thus increasing volume and body.  Perhaps it helped quiet the engine slightly also?   Less obscure is the fact that the ejectors were the carriers for the reverser clamshells.  The whole assembly slid fore and aft under hydraulic power along the track visible on the bottom of the pylon; they were always extended for takeoff and landing.   This photo shows the installation on an Eastern DC-8-21.

Philadelphia, 1966