Time for an Eswube-inspired airliner super-post!
Douglas DC-8
The popular DC-8 was Douglas' first jet powered airliner, and the USA's second successful jet powered transport behind the Boeing 707.
Despite its strong hold on the world airliner market in the early 1950s, and the appearance of the jet powered De Havilland Comet in 1949, Douglas moved cautiously into the field of jet powered transports, a decision which was to cost it dearly in lost potential sales over the following decades.
Douglas announced it was developing the jet powered DC-8 airliner in June 1955, a year after the first flight of the Boeing Model 367-80, the 707 predecessor. The first DC-8 flew on May 30 1958, five months before the 707 entered service with Pan Am. A concerted flight test program involving nine aircraft led to certification being awarded on August 31 1959. Entry into commercial service with launch customers United and Delta was on September 18 that year.
Unfortunately for Douglas, the earlier availability of the 707 meant that initial sales of the DC-8 were relatively slow. However, the emergence of Douglas' design had already forced Boeing to widen the fuselage width of the 707, and unlike the Boeing the DC-8 was offered in domestic and intercontinental versions from the start.
Text pinched from Airliners.net
DC-8-10 Series
Originally known as the DC-8A. Powered by Pratt & Whitney JT3C Turbojets and seating a maximum of 179 passengers in a high-density configuration. Douglas' answer to the Boeing 707.
DC-8-30 Series
JT4A engines, increased fuel capacity and aerodynamic changes to wing surfaces and flap configuration resulted in the -20 and -30 series aircraft. Many earlier -10 series were upgraded to this standard.
DC-8-40 Series
The Rolls Royce Conway turbofan was the major difference between -40 and -30 series aircraft. While not a big seller in the states, most were sold to European airlines. Later -40 series aircraft had further changes to the wing root and leading edge modifications, resulting in extended performance and range.
DC-8-50 Series
The JT3D was the new powerplant for the -50 series. All-cargo and mixed load versions were also developed.
DC-8-61
The -61 was essentaily a -51 with fuselage extended by over 11m to fit more passengers, but sacrificing range. Total of 259 seats in a high-density configuration,
DC-8-62
The -62 was a -50 series design with a fuselage extension of 2m, but with several modifications to both the wings and engine nacelles.
DC-8-63
The -63 had the extended fuselage of the -61, incorporating the modifications of the -62 models.
DC-8-72
The 'Super Seventies' were -60 series aircraft upgraded with CFM56-2 turbofans (in Grumman-designed fairings) and other modifications, including changes to the nose-mounted air inlets.
DC-8-73