If you type "fsx dc8" into a search engine, you will get a confusing mix of freeware, abandonware, and payware. Here is the definitive breakdown of the available models.
For simmers who love classic jet aviation, the Douglas DC-8 holds a special place. As Boeing’s main rival to the 707, the "Eight" was a staple of 1960s and 70s global aviation. In Microsoft Flight Simulator X (FSX), flying a DC-8 offers a unique challenge: it bridges the gap between primitive turbojets and modern high-bypass turbofans.
, but to me, it was a "Battleship Eight"—the most rugged jet airliner ever built.