If You Flew a Short or Medium Distance Segment Over a Nearly 50 Year Period, You Probably Knew the Diesel Nine
The Douglas Aircraft Corporation designed and built many iconic aircraft over the company’s existence between 1921 and 1967 when they became McDonnell-Douglas. Think of any military aircraft name with Sky- as the prefix that comes to mind and you probably picked a winner. But there were more successful Douglas designs that entered production and fought wars than any other manufacturer. An argument can be made that overall Douglas was the most successful designer and builder of aircraft in general because their passenger aircraft designs stacked success upon success for decades.
The Douglas DC-8 was the company’s initial foray into four-engine jet transport, and it did not disappoint. But Douglas had no resume when it came to short / medium range twin-engine jetliners. Initially they took some design cues from British Aircraft Corporation’s BAC One-Eleven (111) and Sud Aviation’s SE 210 Caravelle, both similar in concept to what Douglas had in mind. Bear in mind that the DC-9 was not intended to leverage any components from the DC-8 as Boeing’s 727 leveraged components from the 707, using as many common components as possible. The DC-9 would be a clean-sheet design.
Back to That Douglas Drawing Board
The Caravelle was actually the first jetliner designed for the kind of short/medium distance routes Douglas wanted to service with the DC-9. At one point Douglas intended to license the Caravelle to build a derivative of it in the United States, but when no airlines stepped up and expressed interest in the concept it was dropped and Douglas went back to that very successful and highly experienced drawing board. It took some time and a bunch of pencils, but by 1963 Douglas had a design in mind that resembled both the BAC 111 and the SE210, but ended up outperforming them both where it counted. On 8 April 1963 the design was approved and the DC-9 was conceived.
The DC-9 Difference
The DC-9 would be powered by a pair of Pratt & Whitney JT8D turbofans mounted singly on either side of the rear fuselage of the jet, slightly forward of and under a tall T-tail empennage. This had several advantages. For passengers it meant a quieter ride (unless seated in the extreme rear of the cabin). For baggage handlers it meant baggage compartments were closer to ground level which eased access- no pod-mounted engines on the wings made it possible to equip the DC-9 with shorter landing gear. The engines were also less susceptible to taxiway and ramp foreign object damage (FOD). The short-span swept wings were also more efficient with no engine pods slung under them. Full-span flaps made for greater lift at slower speeds around airpatches.
Taking It With You
Designed for those short / medium duration flights, potentially into austere airpatches, the DC-9 was equipped with built-in air stairs forward and aft under the empennage. Also mounted in the tail was a Garrett GTCP85 auxiliary power unit (APU) that provided power for the aircraft on the ground and eliminated the need for an external starter cart for departure. Like (almost) any airliner the seating configuration of the 122.4-inch width cabin was flexible, but the standard arrangement was five across (usually two on the port side and three on the starboard side) in coach and four across in first class. There were multiple seating variations during the service life of the DC-9. Some cabins were configured four across with first-class seats only.
Ready. Set. Go!
Douglas built the first (and all subsequent) DC-9s in Building 80 at their Long Beach assembly plant. The first DC-9-10 flew for the first time on 25 February 1965. Joined by another four airframes by July, the initial five DC-9s were put through the wringer and were granted certification on 23 November 1965. The initial certification put an 80,000 pound weight restriction on the jet because the crew was limited to pilot and copilot only, but the FAA lifted the restriction within a few months. The first DC-9 to go into passenger airline service was a Delta Airlines DC-9-14 registered as N3305L. The aircraft was received by Delta and flew its first revenue flight as flight 791 from Atlanta to Kansas City with a stop in Memphis on 29 November 1965.
A Great Day for a Small Convertible
The first variant of the DC-9 was the 1X. Operated by more than 50 airlines over its lifespan, the initial DC-9 was quite successful and left airline carrier customers wanting more. DC-9-10s were built in a couple of convertible flavors, both with strengthened floors and a port side 11.4 foot by 6.9 foot cargo door that swung up to allow palletized cargo. The DC-9-15MC (Minimum Change) allowed the passenger seating to be folded up and stowed aft allowing the aircraft to be used for hauling cargo when not hauling passengers. The DC-9-15RC (Rapid Change) had passenger seats mounted on pallets that could be removed and the entire cabin used for cargo. At a length of 104 feet 5 inches the max passenger capacity for the DC-9-10 was 90 pax. Douglas built a total of 137 DC-9-10 series jetliners.