The Douglas DC-9
is a twin engined jet airliner, first manufactured in 1965
and, in much modified form and under a succession of different names, still in production today.
Douglas launched the DC-9 development project in April 1963, intending the DC-9 as a short-range compliment to their larger four engined DC-8. Unlike the competing but slightly larger Boeing 727, which used as many 707 components as possible, the DC-9 was an all-new design, using two rear-mounted Pratt & Whitney JT8D fanjet engines, a small, highly efficient wing, and a T-tail. The original version had five abreast seating for 70 to 90.
The DC-9 prototype flew in February 1965 and entered service with Delta in December of that year. It was an immediate commercial success, and 976 were built by Douglas and then the merged McDonnell Douglas (MDC) before it was renamed MD-80 in 1983. The MD-80 was developed into the MD-90 family which, after the takeover of MDC by Boeing in 1997, became the Boeing 717.
With total sales of over 2400 units, the long-lived DC-9 family is one of the most successful jet airliners ever made, ranking third behind the Boeing 737 (over 5100) and Airbus A320 family (just under 3000).
- DC-9-10 The earliest and smallest DC-9 was 27 m long and had a maximum weight of 41 tonnes. Power was a pair of 54.5 kN Pratt & Whitney JT8D-5s. 137 were built.
- The DC-9-15 and DC-9-20 were minor variations on the -10 theme. The -15 added more fuel capacity and higher weights, the -20 used the more powerful engines and improved wings of the -30 to improve hot and high performance. Only a small number of each were made.
- The DC-9-30 was the definitive model with 662 eventually produced. The -30 entered service in February 1967 with a 4.5 m fuselage stretch, wingspan increased by just over 1 m, weight increaseed to 55 tonnes, and 64 to 67 kN JT8D-9 or JT8D-11 engines. About 380 -30s remained in commercial service in 2002.
- The further stretched DC-9-40 entered service with SAS in March 1968. With a 2 m longer fuselage, accommodation was up to 125 passengers. The -40 was fitted with a variety of Pratt & Whitney engines of between 64.5 and 71 kN. 71 were produced.
- The largest DC-9 to fly under that name was the DC-9-50, which has another 2.5 m fuselage stretch and seats up to 139 passengers. It started revenue service in August 1975 and, aside from the size increase, included a number of detail improvements, a new cabin interior, and quieter JT9D-15 or -17 engines in the 70kN class. McDonnell Douglas delivered 96.