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McDonnell Douglas MD-12

McDonnell Douglas studied improved, stretched versions of the trijet MD-11, with a possible lower-front passenger deck with panoramic windows. The McDonnell Douglas Company (MDC) board of directors agreed in October 1991 to offer the MD-12X design to airlines. MD-12X had a length of 237 ft 11 in (72 m) and wingspan of 212.5 ft (64.39 m). In November 1991, McDonnell Douglas and Taiwan Aerospace Corporation (TAC) signed a Memorandum of Understanding to form a company to produce the new design. The new company would have McDonnell Douglas as the majority shareholder (51%) with Taiwan Aerospace (40%) and other Asian companies (9%) having the remaining shares.

The design then grew into a much larger aircraft with four engines and two passenger decks extending the length of the fuselage, and was announced in April 1992. This was similar in concept to the Airbus A380 and Boeing NLA, and would have been larger than the Boeing 747.

The McDonnell Douglas MD-12 was an aircraft design study undertaken by the McDonnell Douglas company in the 1990s, though it should be noted that this study was a revival of an earlier Douglas study of the 1960s for a double-decker widebody, reprinted in Air International in 2001. Initially it was to be a stretched, higher capacity version of the trijet MD-11. The design then grew into a much larger aircraft with 4 engines and two passenger decks extending the length of the fuselage, and was announced in April 1992.

This was similar in concept to the future Airbus A380 and Boeing NLA, and would have been larger than the Boeing 747. Compared to the Airbus A380, the MD12 would have been shorter (63.4m -v- 73m) and its wingspan would have been a good 15m less (64.9m vs. 79.7) it's tail is about 1.5m shorter as well. But it's cabin width was going to be nearly 3' wider (24'3" -v- 21'6"). Its OEW was going to be about 90,000kgs less (187,000 kgs -v- 276,000kgs) and its MTOW, 130,000kgs less (430k -v- 560k).

Some found the performance claims hard to believe. McDonnell Douglas was going to pack 100 more passengers into an aircraft only 35 tons heavier than a 747-400, and beat the 747-400's range, while using essentially the same class of engines, and with a wing the size of an A340 wing.

Initially offered in Long-Range, High-Capacity, Freight, and Combi versions; later to be offered in Stretch Medium Range, Stretch Long Range, and Twin Engined versions. Full-length two-deck fuselage seating up to 579 passengers in three classes. Range would allow New York to Tapei, Singapore to Zurich, or Los Angeles to Bangkok non-stop. Wing of advanced technology with 35 degree sweep; wing span maintains operational clearance with current taxiway separation standards; seat-mile costs to be 15 percent less than those of current largest airliner.

Fly-by-wire control system with all-glass cockpit; normal ailerons assisted by outboard spoiler panels; four elevator sections; rudders divided into fore and aft and upper and lower panels; total seven spoilers per wing for lateral control. airbrakes and lift dumping; six leading-edge slat and three flap sections per wing. Landing gear was five main legs to carry one four-wheel bogie; inner legs retract into fuselage, outers into wing and fuselage; twin wheel nose leg.

Accommodations were for a two-pilot flight deck on main deck level; possible cross-qualifying with MD-11; crew rest compartment at front end of main upper decks; cabin crew rest area at aft end of upper deck; main deck has two or three aisles; upper deck has two aisles; Long-Range interior seats 481 passengers in three-class layout, including 176 economy class on shortened upper deck plus 24 first class, 90 business class, and 191 economy class on main deck; High Capacity version seated as many as 579 passengers with 107 business class and 93 economy class on full-length upper deck plus 30 first class and 349 economy class on main deck; Combi carriers maximum of nine freight pallets on main deck and 428 passengers; Freight accommodates cargo on both main and upper decks; underfloor freight compartments hold two LD3 containers abreast; eight passenger doors on main deck and four escape doors on upper deck; one stairway standard and second available for High Capacity.

The definitive four-engined layout announced April 1992; development delayed following failure to conclude arrangement with Taiwan Aerospace and prolonged down-turn profitability in airline industry; new risk sharing partners or partner group being sought; low level of development activity in 1994. Despite aggressive marketing, especially in the aviation press, no orders were placed for the aircraft, and it was quietly forgotten after the 1997 merger between McDonnell Douglas and Boeing.

Crew: 2 (1 pilot, 1 copilot)
Capacity 430 Passengers in 3-class arrangement,
up to 511 passengers in high-capacity layout
Dimensions
Wing span 69.80 m 229 ft 0 in
Wing aspect ratio 7.76
Length fuselage 61.32 m 201 ft 2 in
Length overall 63.93 m 209 ft 6 in
Height overall 23.32 m 76 ft 6 in
Tailplane span 25.2 m 82 ft 5 in
Wheel track 11.48 m 37 ft 8 in
Wheelbase 26.82 m 88 ft 0 in
Dimensions internal
Main deck width at floor 6.71 m 22 ft 0 in
Upper deck width at shoulder 5.33 m 17 ft 6 in
Underfloor freight volume 139.3 cu m 4,920 cu ft
Main deck freight volume 538.9 cu m 19,030 cu ft
Upper deck freight volume 198.2 cu m 7,000 cu ft
Areas
Wings, gross 628.1 sq m 6,761.0 sq ft
Vertical tail surfaces (total) 108.7 sq m 1,170.0 sq ft
Horizontal tail surfaces 140.3 sq m 1,510.0 sq ft
Weights and loadings
Operating weight empty Long Range 200,490 kg 442,000 lb
Operating weight empty High Capacity 208,655 kg 460,000 lb
Operating weight empty Combi 209,105 kg 461,000 lb
Operating weight empty Freighter 191,870 kg 423,000 lb
Weight limited payload, Freighter only 143,790 kg 317,000 lb
Max T-O weight Long Range, High Capacity. Combi, Freighter 463,570 kg 1,022,000 lb
Max zero-fuel weight Long Range, High Capacity 290,300 kg 640,000 lb
Max zero-fuel weight Combi 297,100 kg 655,000 lb
Max zero-fuel weight Freighter 328,855 kg 725,000 lb
Max landing weight Long Range, High Capacity 308,445 kg 680,000 lb
Max landing weight Combi 315,245 kg 695,000 lb
Max landing weight Freighter 347,000 kg 765,000 lb
Max wing loading 738 kg/sq m 151.2 lb/sq ft
Power plant Four turbofans
GE CF6-80C2D1F (273.6 kN; 61,500 lb st each) or
Pratt & Whitney PW4462 (275.9 kN; 62,000 lb st each) or
Rolls Royce Trent 764 (284.7 kN; 64,000 lb st each).
Performance (estimated)
Cruising Mach number 0.85
FAA T-O field length (ISA + 30 degrees Celsius) 3,170 m 10,400 ft
FAA landing field length(S/L)
Long Range, High Capacity 2,683 m 8,800 ft
Combi 2,744 m 9,000 ft
Freighter 2,926 m 9,600 ft
Design range
(FAA international reserves and
full passenger payload
freight payload on
Combi and Freighter at
136 kg/cu m; 8.5 lb/cu ft
Long Range 8,090 n miles 14,982 km; 9,309 miles
High Capacity 7,130 n miles 13,204 km; 8,205 miles
Combi 6,360 n miles 11,778 km; 7,319 miles
Freighter 5,000 n miles 9,260 km; 5,753 miles



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Page last modified: 12-07-2014 18:07:37 ZULU