Unbuilt McDonnell Douglas jumbo jets, part 2: the MD-12

In the early 1990s, the Long Beach division of McDonnell Douglas was quite busy with manufacture of the DC-9 derived MD-80 and MD-90 short-haul narrow-body airliners and the MD-11 derivative of the DC-10 trijet widebody airliner, leaving it with a narrower portfolio of in-production airliners than the Boeing company. However, McDonnell Douglas was not standing still when in came to development of widebody airliners, and while it is well known that the Boeing 717 airliner began life as the youngest son of the DC-9, the MD-95, a growing future market demand for a large airliner to handle increased air traffic in the Asia-Pacific realm would give McDonnell Douglas an unlikely impetus to take a second jab at development of a very large airliner.

An artist's concept of the McDonnell Douglas MD-12 trijet, the first airliner to bear the MD-12 designation

With sales of the MD-11 to the airlines coming off to a slow start, in October 1990 McDonnell Douglas proposed a stretched derivative of the MD-11 under the designation MD-12X (the MD-12 designation was first applied to an initial stretched MD-11 proposal with fly-by-wire controls conceived in 1987). The MD-12X was 237 feet 11 in (72.5 meters) long with a wingspan of 212 feet 6 in (64.8 meters), and lacking the MD-11's winglets, it had a seating capacity for 375 passengers in three-class configuration and a range of 10,357 miles (16,668 km). McDonnell Douglas began pitching the MD-12X concept to the airlines in October 1991, and the following month it signed a Memorandum of Understanding with the Taiwan Aerospace Corporation  to form a joint venture to build the MD-12X, with McDD being the majority shareholder (51%) and Taiwan Aerospace (40%) and other Asian companies (9%) having the remaining shares. To help attract foreign investment in the MD-12X project, McDonnell Douglas split its commercial aviation business from the military aviation branch which built the C-17 Globemaster III airlifter.

Company artwork of the McDonnell Douglas MD-12 twin-deck airliner. The similarity to the A380 is quite undeniable.

Although several airlines took an interest in the MD-12X proposal, they increasingly desired a more fuel-efficient four-engine high-capacity airliner with greater growth potential. In response, McDonnell Douglas in April 1992 unveiled the MD-12 four-engine airliner design, which was similar in concept to the Airbus A3XX (later A380) and the Boeing New Large Airplane (NLA) designs. Like the D-916C, D-918, D-950, D-952, and D-956 designs conceived in the mid-1960s, the MD-12 was a twin-deck airliner with turbofans, measuring 208 feet (63.40 meters) in length with a wingspan of 213 feet (64.92 meters), a height of 74 feet (22.55 meters), a wing area of 5,846 ft² (543.1 m²), a gross takeoff weight of 949,000 lb (430,500 kg), and a speed of 650 mph (1,050 km/h). Four baseline MD-12 variants were offered, the 430-seat MD-12 Long Range design with a range of 9,229 miles (14,853 km), the 511-seat MD-12 High Capacity design with a range of 8,251 miles (13,279 km), the 430-seat MD-12 Combi passenger/cargo variant with a range of 7,169 miles (11,537 km), and the MD-12 Freighter with a cargo capacity of 274,600 lb (124,556 kg). The 689-seat MD-12 Stretch was to be 26 feet 6 in (8 meters) than the baseline MD-12 with a wingspan of 229 feet (69.8 meters), and two subvariants were offered, the MD-12 Stretch MR (Medium Range) with a range of 5,800 miles (9,334 km) and the MD-12 Stretch LR (Long Range) with a range of 7,800 miles (12,553 km). The 430-seat MD-12 Twin had the same length as the basic MD-12 but had the same wingspan as the MD-12 Stretch, two turbofan engines, and a range of 5,000 miles (8,046 km). Engine options for the baseline MD-12 and MD-12 Stretch MR included the 61,500 lb (274 kN) thrust General Electric CF6, four 62,000 lb (28,122 kg) thrust Pratt & Whitney PW4400, and the 64,000 lb (29,029 kg) thrust Rolls-Royce Trent 764, while turbofans with 90,000 lb (400 kN) thrust were planned for the MD-12 Stretch LR and MD-12 Twin. Like the MD-11, the MD-12 had crew of two and a glass cockpit, and it sported winglets similar to those developed for the A380. With a fuselage measuring 24 feet 3 in (7.4 meters) wide and 27 feet 11 in (8.5 meters) high, it would have been the most spacious airliner with either a two- or three-aisle cabin. The MD-12 would offer passengers the roomiest and most comfortable cabins in the sky, and the passenger decks featured the latest in passenger amenities with options including an office in the sky, exercise room, in-seat video, and seat telephones.

Given expected high development costs of the MD-12, the planned joint venture between McDonnell Douglas' commercial aircraft business and Taiwan Aerospace would combine the McDonnell Douglas resources located in the United States and Taiwan. Significant parts fabrication and major sub-assembly work was to be undertaken in Taiwan, and the final assembly of the MD-12 would take place at a new site in the United States (Belleville, Fort Worth, Houston, Kansas City, Mesa, Mobile, Salt Lake City, Shreveport, and Tulsa were accepted as candidates for an MD-12 final assembly facility). Plans called for the MD-12 to make its first flight in 1995 and enter service in 1997, but the MD-12 project was all for naught. No airline orders were placed for the MD-12 despite an aggressive marketing campaign by McDonnell Douglas, and when Taiwan Aerospace decided to quit participation in the MD-12 program, a financially cash-strapped McDonnell Douglas, lacking any other equity partners to keep the MD-12 alive, instantly shelved the MD-12 project.

References:

Norris, G., and Wagner, M., 2005. Airbus A380: Superjumbo of the 21st Century. St. Paul, MN: Zenith Press.

Steffen, A., 2002. McDonnell Douglas MD-11: A Long Beach Swansong. Hinckley, UK: Midland Publishing.