The Douglas DC-8 was - just like the Boeing 707 - originally conceived in response to a requirement from the US Air Force for a jet aircraft capable refuelling fast fighters and bombers. Having lost the contract to Boeing, Douglas immediately transformed the design to a jet transport.
The DC-8 has a conventional configuration with low mounted, swept wings, horizontal stabilisers attached to the rear fuselage and four jet engines in pods under the wings. There are two distinctive features on the DC-8, the single eyebrow cockpit windows and above all the air intakes at the side of the nose, for the cabin pressurisation.
How to recognise the different versions of the Douglas DC-8 will be added later.
Confusion possible with
The Convair 880 and 990 are most easily confused with the DC-8. However, a look at the nose is enough to keep them apart, as the Convair aircraft have no eyebrow cockpit windows and no air intakes in the nose.
The Boeing 707 and all its variants (including the C-135 Stratotanker) also look similar. They can best be recognised by the forward pointing antenna on top of the vertical stabiliser and the two eyebrow cockpit windows on each side. Also they have no air intakes at the side of the nose.
The Shanghai Y-10 has more resemblance to the Boeing 707/720, as it formed the basis for the Chinese reverse engineered aircraft. The main differences with the DC-8 are in the nose shape and cockpit windows. (photo: Zhangmingda/WikiMedia)
The slim engine nacelles may fool you but the Il-86 is much bigger than the DC‑8; it is a wide body, while the DC‑8 is a narrow body aircraft. Like the aircraft types described above it also lacks the distinctive features of the DC‑8's nose.