The McDonnell Douglas MD-94X was a planned
propfan
A propfan, also called an open rotor engine, open fan engine is an aircraft engine combining features of turbofans and turboprops. It uses advanced, curved propeller blades without a ducted fan, duct. Propfans aim to combine the speed capabili ...
-powered
airliner
An airliner is a type of airplane for transporting passengers and air cargo. Such aircraft are most often operated by airlines. The modern and most common variant of the airliner is a long, tube shaped, and jet powered aircraft. The largest ...
, intended to begin production in
1994
The year 1994 was designated as the " International Year of the Family" and the "International Year of Sport and the Olympic Ideal" by the United Nations.
In the Line Islands and Phoenix Islands of Kiribati, 1994 had only 364 days, omitti ...
. Announced in January 1986,
the aircraft was to seat between 160 and 180 passengers,
possibly using a twin-aisle configuration.
An all-new design that was investigated internally since at least 1984,
the MD-94X was developed in the mid-1980s to compete with the similar
Boeing 7J7. The
price of oil
The price of oil, or the oil price, generally refers to the spot price of a barrel () of benchmark crude oil—a reference price for buyers and sellers of crude oil such as West Texas Intermediate (WTI), Brent Crude, Dubai Crude, OPEC ...
would have to be at least US$1.40 per gallon for McDonnell Douglas to build the plane, though.
Configuration was similar to the MD-80, but advanced technologies such as
canard noseplanes,
laminar
Laminar means "flat". Laminar may refer to:
Terms in science and engineering:
* Laminar electronics or organic electronics, a branch of material sciences dealing with electrically conductive polymers and small molecules
* Laminar armour or "bande ...
and
turbulent
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
boundary layer control
In engineering, boundary layer control refers to methods of controlling the behaviour of fluid flow boundary layers.
It may be desirable to reduce flow separation on fast vehicles to reduce the size of the wake (streamlining), which may reduce ...
,
side-stick
A side-stick or sidestick controller is an aircraft control stick that is located on the side console of the pilot, usually on the righthand side, or outboard on a two-seat flightdeck. Typically this is found in aircraft that are equipped with ...
flight control (via
fiber optic
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at ...
s), and
aluminum-lithium alloy construction were under consideration.
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.
Under development at the same time were two propfan-powered commercial variants of the
MD-80
The McDonnell Douglas MD-80 is a series of five-abreast narrow-body aircraft, single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. 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,
was originally to be a of the MD-80.
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
Pratt & Whitney is an American aerospace manufacturer with global service operations. It is a subsidiary of RTX Corporation (formerly Raytheon Technologies). Pratt & Whitney's aircraft engines are widely used in both civil aviation (especially ...
JT8D-200 series engines.
Existing
DC-9
The McDonnell Douglas DC-9 is an American five-abreast, single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced as the Douglas DC-9 prior to August 1967, after which point the company had merged with McDonnell A ...
s and MD-80s would also have been eligible for an upgrade to the new propfan powerplants.
On May 19, 1987, McDonnell Douglas tested
General Electric Aviation
General Electric Company, doing business as GE Aerospace, is an American aircraft engine supplier that is headquartered in Evendale, Ohio, outside Cincinnati. It is the legal successor to the original General Electric Company founded in 1892, wh ...
's
unducted fan (UDF) engine in flight for the first time on an MD-80 demonstrator,
an aircraft that was restored after suffering an
empennage
The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...
separation in 1980 during the landing of a certification test flight for the
DC-9 Super 80.
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
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
's Long Range Air ASW-Capable Aircraft (LRAACA) program, which was to initially replace the existing fleet of 125
Lockheed P-3 Orion
The Lockheed P-3 Orion is a four-engined, turboprop Anti-submarine warfare, anti-submarine and maritime patrol aircraft, maritime surveillance aircraft developed for the United States Navy and introduced in the 1960s. It is based on the Lockheed ...
aircraft.
In October 1988, the Navy selected a derivative of the P-3 Orion (which was later renamed
Lockheed P-7
The Lockheed P-7 was a four turboprop-engined patrol aircraft ordered by the U.S. Navy as a replacement for the P-3 Orion. The external configuration of the aircraft was to be very similar to that of the P-3. Development had not progressed very ...
A) as the LRAACA aircraft over the P-9D.
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.
Specifications
See also
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{{Douglas airliners
Abandoned civil aircraft projects of the United States
MD-094X
Propfan-powered aircraft
Low-wing aircraft
Twin-engined pusher aircraft
Aircraft with retractable tricycle landing gear