McDonnell Douglas MD-94X

The McDonnell Douglas MD-94X was a planned propfan-powered airliner, intended to begin production in 1994. Announced in January 1986,[1] the aircraft was to seat between 160 and 180 passengers,[2] possibly using a twin-aisle configuration.[3] An all-new design that was investigated internally since at least 1984,[4] the MD-94X was developed in the mid-1980s to compete with the similar Boeing 7J7. The price of oil would have to be at least US$1.40 per gallon for McDonnell Douglas to build the plane, though.[5] Configuration was similar to the MD-80, but advanced technologies such as canard noseplanes,[6] laminar and turbulent boundary layer control, side-stick flight control (via fiber optics), and aluminum-lithium alloy construction were under consideration.[7] Airline interest in the brand-new propfan technology was weak despite claims of up to a 60% reduction in fuel use, and both aircraft were canceled.

MD-94X
A model of the proposed McDonnell Douglas MD-94X clean-sheet aircraft with two propfan engines.
Role Airliner
National origin United States
Manufacturer McDonnell Douglas
Status Canceled project
Number built None
Developed from McDonnell Douglas MD-80

Under development at the same time were two propfan-powered commercial variants of the MD-80. The "MD-91X" would have seated 100-110 and entered service in 1991. The "MD-92X," a 150-seat aircraft targeted for service entry in 1992,[2] was originally to be a 76 in stretch (1.9 m) of the MD-80.[3] The price per engine would have been an estimated US$1.6 million dollars more for the propfans than for the MD-80's Pratt & Whitney JT8D-200 series engines.[8] Existing DC-9s and MD-80s would also have been eligible for an upgrade to the new propfan powerplants.[9] On May 19, 1987, McDonnell Douglas tested General Electric Aviation's unducted fan (UDF) engine in flight for the first time on an MD-80 demonstrator,[10] an aircraft that was restored after suffering an empennage separation in 1980 during the landing of a certification test flight for the DC-9 Super 80.[11]

A propfan-powered military variant of the MD-87 or MD-91X, called the P-9D, was also proposed as an anti-submarine warfare (ASW) aircraft. The P-9D was intended for use in the United States Navy's Long Range Air ASW-Capable Aircraft (LRAACA) program, which was to initially replace the existing fleet of 125 Lockheed P-3 Orion aircraft.[12] In October 1988, the Navy selected a derivative of the P-3 Orion (which was later renamed Lockheed P-7A) as the LRAACA aircraft over the P-9D.[13]

On October 10, 1989, McDonnell Douglas publicly announced that it was abandoning the development of propfan-powered aircraft, because of airline companies were concerned about the technology risk and cost compared to a conventionally-powered airliner.[14]

Specifications
A desktop scaled model of the proposed McDonnell Douglas MD-91 propfan airliner.
Characteristics
Airplane MD-91X[15] MD-92X[15] MD-94X P-9D[12]
Derived from[9] MD-87 MD-88 N/A (clean sheet) MD-87 or MD-91X
Mixed-class seats 114 165 N/A
Sale price[16] US$25 million >US$30 million
Length 120 ft 11 in (36.86 m)[17] 157 ft 4 in (47.96 m)[17] 132 ft 2 in (40.3 m)
Operating empty weight 83,508 lb (37,879 kg) 91,579 lb (41,540 kg)
MTOW 133,000 lb (60,000 kg) 155,000 lb (70,000 kg) 165,000 lb (75,000 kg)
Cruise speed Mach 0.76 430 knots (490 mph; 800 km/h)
Range 2,563 nmi (2,949 mi; 4,747 km) 2,424 nmi (2,789 mi; 4,489 km) 2,000 nmi (2,300 mi; 3,700 km) (4-hour loitering time)
Takeoff field length[18] 5,200 ft (1,600 m) 7,000 ft (2,100 m)
Engines (×2) General Electric GE36-C22
or PW-Allison 578		 General Electric GE36-C25
or PW-Allison 578		 General Electric GE36 or PW-Allison 578-D[13]
Thrust per engine 22,000 lbf (98 kN) 25,000 lbf (110 kN) 25,000 lbf (110 kN)
Lower hold cargo volume 773 cu ft (21.9 m3) 1,250 cu ft (35 m3) N/A

See also

Related development

Aircraft of comparable role, configuration, and era

References
  1. Ramsden, J. M. (February 22, 1986). "Propfans—'the genie is out of the bottle'" (PDF). Air Transport. Flight International. Vol. 129, no. 3999. New Delhi, India. p. 8. ISSN 0015-3710. Retrieved May 17, 2019.
  2. Haggerty, James J. (1987-08-01). "Toward future flight". Spinoff (PDF) (1987 ed.). NASA (published August 1987). pp. 30–33. hdl:2060/19880002195. OCLC 17914180. Archived from the original on April 12, 2009.
  3. Kehe, R. N.; Morrison, Jr., H. F. (September 15–18, 1986). Cargo airlift: what's old? What's new?. International Forum for Air Cargo and International Air Cargo Exposition. SAE Technical Papers (13th ed.). Basel, Switzerland (published October 1986). doi:10.4271/861152. ISSN 0148-7191. JSTOR 44470563. OCLC 5818017739.
  4. Hawley, Arthur V. (July 1993). Development of stitched/RTM primary structures for transport aircraft (Report). Vol. CR-191441. McDonnell Douglas Aerospace - Transport Aircraft. p. 13. hdl:2060/19950025000. OCLC 34053899 – via NASA.
  5. Moll, Nigel (December 1986). "GA strong at Farnborough". Minifeature. Flying. Vol. 113, no. 12. pp. 96–97. ISSN 0015-4806.
  6. Green, William; Swanborough, Gordon; Mowinski, John (12 September 1988). Modern commercial aircraft. Portland House (published November 1, 1988). ISBN 9780517633694.
  7. Morris, John (September 7–12, 1986). A propfan status report (PDF). International Council of the Aeronautical Sciences (15th ed.). London, England, United Kingdom. pp. 1091–1098.
  8. Harr, Amy, ed. (January 1990). "Propfan is shelved". Reporting Points. Flying. Vol. 117, no. 1. p. 13. ISSN 0015-4806.
  9. Learmount, David (June 13, 1987). "Propfan: the price factor". Flight International. Seattle, Washington and Long Beach, California, USA. pp. 76–79. ISSN 0015-3710. Retrieved May 19, 2019.
  10. Mongelluzzo, Bill (May 19, 1987). "New engine gets first test flight". Journal of Commerce. ISSN 1530-7557.
  11. "Hard landing: The demonstration MD-80 slammed into runway, lost its tail". History. Avgeekery.com. December 25, 2017. Retrieved March 28, 2023.
  12. "MDC studies propfan ASW" (PDF). Defence. Flight International. Vol. 132, no. 4076. Long Beach, California, USA. August 22, 1987. p. 8. ISSN 0015-3710.
  13. Bailey, John (September 2, 1989). "After Orion". Flight International. Vol. 136, no. 4180. Los Angeles, California, USA. pp. 31–33. ISSN 0015-3710.
  14. Vartabedian, Ralph (October 11, 1989). "Douglas unveils 2 jets, drops prop fan". Los Angeles Times. ISSN 0458-3035.
  15. Henne, P. A. (July 31 – August 2, 1989). MD-90 transport aircraft design. AIAA/AHS/ASEE Aircraft Design, Systems and Operations Conference. Seattle, Washington, USA. doi:10.2514/6.1989-2023. OCLC 1109563682.
  16. Donne, Michael (September 7, 1988). "Farnborough International Air Show: US launches propfan sales drive". UK News. Financial Times. No. 30635. p. 8. ISSN 0307-1766.
  17. "Douglas ponders MD-80 stretch" (PDF). Flight International. Vol. 134, no. 4140. November 19, 1988. p. 17. ISSN 0015-3710.
  18. at MTOGW, sea level, 84 °F (29 °C)

Bibliography
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