The Mcdonnell * Douglas MD-80
I
Fuselage stretchability, inherently incorporated in the fundamental DC-9 design, had characterized its
program, resulting in four dimensionally divergent, higher-capacity versions, including the initially-
elongated DC-9-30 over the baseline sequence -10/14/15, the subsequent DC-9-40, and the final DC-
9-50, the latter accommodating forty-nine more passengers compared to twin-jet's original highest.
The DC-9 by itself, founded upon the four design tenets of ruggedness, simplicity, stability, and low-
cost, have been McDonnell-Douglas's best-selling commercial aircraft-so much so, in fact, that it took
off or landed somewhere on the globe every seven mere seconds, serving more than 570 cities with
some six,050 daily travel arrangements, and by 1979, your collective fleet had carried more than one
million passengers and drenched more than 18 trillion hours with an practically 99-percent dispatch
trustworthiness rate.
Its Pratt and Whitney JT8D engine, the most popular powerplant and numbering in excess of 12,500
units, had not merely provided propulsive pushed for all versions of the DC-9, but got also powered
your Boeing 727, the Sud-Aviation SE.210 Super Caravelle, your Boeing 737, as well as the
Dassault-Breguet Mercure one hundred.
Both the DC-9's basic design and its particular JT8D turbofan therefore offered the most optimum,
cost-effective platform on which to base any larger-capacity successor, which usually needed to
equal the actual DC-9-30's range capability, yet exceed the DC-9-50's economics.
Its fuselage, not having achieved its limit regarding stretchability, lent by itself to still higher-capacity
accommodation, but its barrier had been a powerplant of sufficient forced to maintain acceptable
payload, range, and performance guidelines for its operators.
Based upon the earlier, two-stage JT3D, which had powered both the 707 and also the DC-8, the
JT8D, a low, one-to-one avoid ratio turbofan, acquired first run on the spring 7, 1961, getting to the
skies initially on May one of the following year mounted to a 707. Obtaining FAA certification on
february 9, 1963, since the 14,000 thrust-pound JT8D-1, it had powered the 727-100 before being
employed with the DC-9-10 and has been subsequently offered in lots of successively higher-thrust
versions, the last of which had recently been the 17,500 thrust-pound JT8D-17R.
A new-generation variant, offering application for an ultimate DC-9 stretch and also designated JT8D-
109, ended up one of six demo powerplants incorporating more substantial, single-stage fans
designed for NASA's calm Engine Program, which had run between 1973 and 1975, and a couple of
its versions acquired logged more than 50 hours retrofitted to some modified DC-9-32. Design and
style of a further advancement, the 18,five hundred thrust-pound JT8D-209, commenced in 1974 as
well as first ran couple of years later, test flown on a McDonnell-Douglas innovative Medium STOL
transfer (AMST) in goal of 1977.
Although a new, supercritical wing had also at first been considered, the actual aircraft, intended for
short- to medium-range sectors which entailed greater ratios of climb-and-descent to actual cruise
profiles, could not totally exploit such a brand-new design, its advantages resultantly unable to
rationalize its higher development costs. The existing DC-9 wing, incorporating main and tip
extensions and modified high-lift devices, would provide the mandatory performance, economy, and
also range parameters.
Several initial iterations, generally based upon the DC-9-50 and all featuring fuselage stretches for
increased capacities, larger-area wings, and two refanned turbofans, had included your refan-
stretched DC-9-50RS, the particular refan-super stretched DC-9-50RSS, the DC-9-55, and also the
DC-9-60, while a new DC-9QSF, intended for japoneses operators as an NAMC YS-11 twin
turboprop replacement, mated a DC-9-40 airframe with two 18,000 thrust-pound JT8D-209 engines
and a two-foot bigger wing, enabling the 114,000-pound jet to operate from several,000-foot runways
with 120 passengers.
However, cost constraints and also design complexities influenced a simpler, more easy version
which integrated the longer fuselage, increased-area wings, and also JT8D-209 turbofans, yet
retained cockpit commonality with all previous DC-9 variants. Skipping the DC-9-60 and DC-9-70
sequences, the defined aircraft, designated DC-9-80-or DC-9 Super 70, to more accurately echo the
intended calendar year of service inauguration-had already been launched on april 20, 1977 with the
receipt of 29 firm and tough luck optioned orders via Swissair, Austrian airways, and Southern air
passage, along with a letter regarding intent from LAV Lineas Aeropostal Venezolanas, all of which
had been earlier DC-9 operators. Envisioned as a higher-capacity enhance to its DC-9 airframe and a
replacement higher-cost tri-jets, that intended to provide service in maturing markets whose
environmental and noise restrictions had precluded larger-capacity tools substitution, the planes
offering a significantly smaller noise impact, greater range and also capacity, and the cheapest seat-
mile costs involving any comparable twin-jet.
According to then-President of the Douglas plane Company, John c. Brizendine, "In recent
years...we've got become acutely mindful of the need to conserve energy, to protect the environment,
and to produce more and more economically efficient aircraft. (the particular DC-9 Super 50 ) is
specifically designed in order to meet the requirements of our business for years to come. These
include environmental compatibility, power efficiency, economical functioning, and a spacious, comfy
interior."
McDonnell-Douglas boasted of the aircraft, "the DC-9 Super eighty is a blend of confirmed design
with obtainable low-risk technology with regard to enhanced effectiveness, (nevertheless ) the
remarkable DC-9 reliability and lower functioning costs are taken care of."
Although it had been considering this earlier-generation dual, it nevertheless released several
advanced capabilities.
A fuselage extend, attained by means of the eight-frame plug onward of the wing and a single-frame
insertion aft of it, resulted in any 147.10-foot all round length, increasing maximum capacity to 172, or
33 greater than the DC-9-50 and a staggering 82 over the initial DC-9-10, and also producing the
most greatly stretched commercial airliner up to that time. The forward, left, along with aft, ventral,
making a profit, both equipped with extendible airstairs, had been stored, but an aft, left servicing
front door, located only foot from the engine, was introduced. Aeritalia regarding Naples, Italy,
produced its fuselage sections.
A new, 15.6-foot center section and two-foot parallel-chord tip extensions, resulting in the third
dimensionally divergent DC-9 wing, yielded a 28-percent location, 57-percent fuel ability, and 11-
percent effectiveness increase.
Measuring 107 feet, 10 1/4 inches, the airfoil, with a 24-degree mop back at their quarter chord, the
9.62 element ratio, three degrees of dihedral, and a one,239 square-foot area, had been comprised of
four per-wing precision-machined pores and skin panels which had recently been transformed from
18,000-pound ingots calculating 60 inches extensive, 15 inches long, and 30 inches thick by the
Reynolds Metal Company regarding McCook, Illinois.
The all-metal, two-spar construction, with riveted spanwise stringers, featured full-span, three-position
leading edge panels with a new, intermediate environment to decrease take off drag and improve
climb performance at increased gross weights; larger, doubled-slotted, trailing edge flaps which
covered 67 percent from the span and diminished the aircraft's waiting speed; three spoiler panels,
the exterior two of which have been employable as equally flight and ground lift dumpers; and also
ailerons. All but the second were hydraulically actuated, while the ailerons by themselves were
manually controlled. An underwing vortillon fence ensured proper airflow. Providing 1,520 US gallons
of additional fuel tankage, it also offered an increased-area main undercarriage bay.
The variable-incidence, electrically-actuated horizontal end, spanning 40.only two feet, or several.6
feet in addition to that of the DC-9-50, maintained the design's characteristic t-tail configuration and
sported assister tab-equipped elevators, while the straight fin, rendering a general aircraft height
regarding 30.2 ft, featured a hydraulically-actuated rudder. It had been a single.4 feet above the DC-
9-50's.
Its Pratt and Whitney JT8D-209 turbofan, mounted on either side of the aft fuselage and holding onto
the original target-type forced reversers, was considering the core in the earlier JT8D-9, however
introduced a 49-inch wider fan as well as an advanced, low-pressure converter, producing 18,five-
hundred pounds of thrust along with an additional 750 pounds of programmed power reserve (apr
interest rates ), generated during engine-loss conditions. The larger-diameter, single-stage fan,
generating a larger mass regarding hot core section-bypassing air, coupled with better hot and cold
exit duct intermixing air, and also increased sound absorption material in its nacelle and surrounding
covering, yielded numerous advancements, inclusive of increased thrust capability; a higher get
around ratio-of 1:one.78 as opposed to the earlier JT8D's 1:one ; a lower exit pace ; an 11-percent
loss of specific fuel ingestion ; and a significantly scaled-down noise footprint compared to the
medium-range tri-jets it had been intended to replace.
Employing weight-reducing Kevlar-reinforced aluminum honeycomb stiffeners with graphite mp3 caps
in the exterior barrel of its nasal cowl and its upper and two lower cowl doors, the nacelle, 21.1 foot
long, was some.5 feet longer than the JT8D-9's and thus presented engineering issues relative to its
installation on the DC-9's, albeit longer, body.
The DC-9 Super 70 retained the hydraulically-retractable, tricycle, dual-wheeled, Cleveland
Pneumatic undercarriage, installed with Goodyear trolley wheels, tires, and dvd brakes; Hydro-Aire
Mk IIIA antiskid products ; and Douglas leaped air brake air conditioning. The nose controls was
steerable to be able to 27 degrees with the idea to side.
Although the Super 80 stored a common pilot kind rating with the DC-9, it nevertheless offered
several cockpit improvements, including a digital and also flight guidance manage system designed
by the actual Sperry Flight methods Division of Sperry Rand Corporation, which integrated the
performance of seven airfare control subsystems straight into two identical electronic digital
computers; cathode ray tube (CRT) shows ; a digital fuel volume gauge system; the dial-a-flap
system; along with Category IIIA autoland capability of 50-foot decision height (DH) and also 700 feet
involving runway visual selection (RVR). A after introduced Electronic efficiency Management System
provided automatic pitch as well as thrust to effectuate optimum speed and fuel burn throughout the
aircraft's climb, luxury cruise, and descent profiles.
The 101-foot-long, "extensive look" cabin, highlighted a broad, contoured, and also sculpted
acoustically-treated limit which blended in with the enclosable expense storage compartments;
aluminium sidewall panels sculpted round the windows; fluorescent lighting; a 19-inch aisle; and five-
abreast, two-three or three-two, configured economy school seating, which lowered by half the
amount of middle seats typically associated with six-abreast preparations.
Interior decor, which in turn varied from conventional, business-oriented appointment to bold patterns
as well as bright colors, had been determined by the operator and custom-designed by McDonnell-
Douglas whose interior design teams often created trips to airline home countries in order to absorb
local traditions and customs after which convert that experience directly into area- or country-
reflective motifs. Wool along with wool synthetic blends were standardly used for seat covers and
carpets.
Class along with seating configuration every bit as varied according to agent. A 137-passenger, dual-
class arrangement, for instance, entailed 12 four-abreast top class seats at a 38-inch pitch and a
hundred twenty five five-abreast economy type seats at a 34-inch pitch, while single-class densities
included 155 passengers at a 32/33-inch pitch, 167 constitution seats at a 30-inch pitch, or a more
172 high-density people, the latter accommodatable using a single galley set up.
Interior noise reduction was attained through an insulating quilt of fabric-reinforced Mylar over
fiberglass.
The elongated DC-9 presented a new pressurization along with air circulation system, which usually
replaced cabin air at greater wavelengths, and its potable normal water system featured in-line
heaters in all of their water lines. An increased-capacity auxiliary strength unit (APU) ran its
environmental manage system on the ground.
The aircraft's longer fuselage significantly increased their lower-deck baggage as well as cargo
compartment quantity, whose forward, middle, and aft holds respectively encompassed 434, 376, and
443 cubic feet.
The DC-9-80 retained 80 percent of the DC-9-50's important maintenance features.
Like all of its previously, shorter-fuselage predecessors, the actual aircraft had been created for short-
sector, rapid-turnaround, self-sufficient operations from brief, limited-facility airfields, having its
increased thrust, larger-area wings, self-contained airstairs, auxiliary power unit for environmental
health and fitness and engine begins, low-to-ground profile to be able to facilitate servicing,
launching, and maintenance, along with ability to operate several sectors without the need for
refueling. Most turnarounds required little more than baggage carts.
With any maximum structural payload of 40,112 pounds, the DC-9-81, as designated in the initial
variant, were built with a 147,000-pound uncouth weight, although this have been later increased for
you to 149,500 weight with uprated engines, and a maximum obtaining weight of 128,000 pounds.
Their normal and maximum cruise speeds were, respectively, Mach 0.76 and 3.80. Range, together
with 155 single-class people and domestic supplies, was 1,564 nautical miles.
Piloted by Douglas chief Engineering Pilot they would. H. "Knick" Knickerbocker, Project Pilot bob P.
Laine, and also Flight Test engineer Virginia "Ginny" a. Claire, the first DC-9 Super 80 as well as the
909th twin-jet in order to roll off the lengthy Beach assembly series, made its maiden flight from
lengthy Beach Municipal Airport's Runway 30 on October 18, 1979 with call sign DACO 80-for
"Douglas Aircraft Company 80."
Following a 25-mile circular, overwater pattern, the long, slender-fuselage aircraft, accommodating
13,100 pounds of test equipment, concluded a successful two-hour, 50-minute basic-maneuvers test
sortie before landing from McDonnell-Douglas's Flight surgical procedures Facility in Yuma, Arizona,
where the chief Engineering Pilot deducted, "The ground handling from the Super 80 can be even
better than the some other DC-9s. It also appeared quite stable in flight...The new engines were
faultless, and the invert thrust was effective on landing...in my opinion the Super 80 is a great airplane
and definately will live up to all our expectations."
The 1,085-hour, $36 million, three-aircraft flight test plan, which entailed very first flights of model
N1002G on dec 6, 1979 along with N1002W on February twenty nine, 1980, led to federal aviation
administration certification seven several weeks later, on july 26, under the amendment to the DC-9's
original type document.
First delivered to start customer Swissair on September 12, which had operated earlier DC-9-15, -30,
and -50 series, it was inaugurated into scheduled assistance on October your five from Zurich in
order to Frankfurt, becoming the particular quietest commercial pure-jet. Co-launch customer Austrian
Airlines, which had every bit as operated a fleet of DC-9-30s and -50s, inaugurated its first revenue
service a three week period later, on oct 26, from Vienna to Zurich.
In order to adopt the actual McDonnell-Douglas designation plan, the DC-9-80, or even DC-9 Super
50, was rebranded the "MD-80" in 1983, its initial version dubbed "MD-81."
II
Development of the baseline Pratt and Whitney JT8D-209 engine, resulting in the uprated, 20,000
thrust-pound -217, augmented extra versions, the origin of which had been the 1979 requirement for
a short lose and landing (STOL) aircraft to operate from the Japanese domestic market place. A then-
projected technology, designated DC-9 ultra 80SF, would have mated the DC-9-40's fuselage with
the DC-9-80's mentorship and engines, though the higher-thrust JT8D-217, applied to existing
fuselage dimensions, would have provided almost all of the desired performance. Resultantly, a
second variant, chosen MD-82 and very first announced on april 16, 1979, featured the uprated,
twenty,000 thrust-pound turbofans with 850 lbs of automatic energy reserve, a 46,024-pound
payload, plus a 2,050-mile array with 155 passengers. First flying upon January 8, 1981, it received
their FAA type accreditation six months later, in July 31, at an initial 147,000-pound maximum take off
bodyweight, although the 1982 choice of JT8D-217A search engines further increased this specific to
149,five hundred pounds, resulting in still-higher payload and range capabilities.
Republic airways, the July a single, 1978 amalgamation involving North Central and Southern
Airways, have been the version's launch customer, having been the world's largest DC-9 agent with
series -10s, -30s, and -50s, to which its ten MD-82s were sooner or later added.
The variant had been involved in 2 unique programs. The first of these, occurring throughout October
of 1982, entailed the revolutionary lease of 20 MD-82s to united states Airlines, for which McDonnell-
Douglas agreed to bear the constant maintenance and training costs. This let on the February 1984
buying 67 aircraft, in attractive prices and with low cancellation penalties, to be delivered within blocks
of 15 to 25 airframes, each block that had been confirmable couple of years before the targeted
shipping date. Becoming the actual mainstay of American's short- to medium-range fleet to help hub
connections inside Chicago and texas, the aircraft, designed for 142 initial and economy class
passengers, ultimately numbered 234, the world's largest, single-type total outside of the former
USSR.
The second innovative financial transaction occurred on the spring 12, 1985, in the event the
Shanghai Aviation commercial Corporation agreed to license-build 25 MD-82s within the People's
Republic associated with China.
An extended-range successor, designated MD-83 and first announced on January 31, 1982,
introduced even now higher-rated engines. The particular JT8D-219, rated at twenty one,000 pounds
of thrust, featured a new redesigned low-pressure turbine, a new high-pressure turbine,
aerodynamically improved airfoils, a five-percent rise in thrust, and a two-percent reduction in fuel
burn off.
First flying about December 17, 84, the twin-jet, which has a 160,000-pound optimum take off weight,
provided a 2,502-nautical distance range, attained by means of 1,160 all of us gallons of additional,
decrease deck hold-installed second fuel tanks. Finnair, which had operated the particular DC-9-
14/15, -40, and -50, served because the version's launch customer, operating the top, nonstop MD-80
trip on November 18, 1985, when this covered the 3,406-mile distance between Montreal and
Helsinki throughout seven hours, 26 minutes. Transwede, regarding Sweden, inaugurated the 1st
revenue-earning trans-Atlantic airline flight from Stockholm to Ft. Lauderdale using intermediate stops
throughout Oslo and gander.
In order to offer a lower-capacity counterpart more desirable to reduced-demand industries, and to
more effectively contend with the 737-300 Boeing designed for this market, McDonnell-Douglas
offered the first, and only, dimensionally-divergent variant, the actual MD-87, which had started out its
earlier, DC-9 Super XX research for a 100- in order to 120-passenger aircraft driven either by Pratt
and Whitney JT8D-200 series or CFM International CFM56-3 turbofans and offering a new 110,000-
to be able to 120,000-pound uncouth weight. The alternative, with a 16.5-foot shorter fuselage,
presented a new, 130.5-foot overall length together a 38,726-pound maximum payload, or perhaps
the same as the DC-9-50's.
Because of the lowered moment-arm of the quicker fuselage, vertical axis control required the larger-
area, ten-inch higher fin, visible through the extension above their traditional t-tail mating point and
producing a new, 31.2-foot overall height. In addition, it introduced low-drag flap hinges and fairings,
a fillet fairing between the fuselage and also the engine pylon, and a reduced-drag, blade-shaped
tailcone.
Initially powered by the 20,000 thrust-pound JT8D-217B, but after retrofitted with the lower fuel
consumption -217C version, the MD-87 had a 2,372-nautical mile range together with 130
passengers and also domestic reserves, even though additional, MD-83 sort fuel tankage in the lower
holds increased this to 2,833 miles.
First using to the skies upon December 4, 1986, it received its FAA type qualification on October 21
years old of the following calendar year, and was inaugurated into service about December 17 with
Austrian Airlines coming from Vienna to Zagreb.
The last, and quite a few advanced, of the five versions, the MD-88, reintroduced the original fuselage
dimensions and has been announced on jan 23, 1986 after launch customer Delta Air Lines placed
an initial order to be able to 80 of the variety. Offered with 21 years old,000 thrust-pound JT8D-219
turbofans, the variation, most closely good MD-82, featured elevated composite material to relieve
structure weight, a whole new passenger cabin with a wider aisle as well as modernized overhead
hard drive compartments, and a professional, glass cockpit, the latter comprised of an electronic
airline flight instrument system (EFIS), a flight management program (FMS), and an inertial reference
program (IRS). It stored the MD-87's blade-shaped tailcone.
First hurtling on August 16, 1987 and FAA-certified four months afterwards December 9, the actual
MD-88 entered timetabled service with Delta on January a few, or just over twenty-two years after the
idea had operated earth's first passenger-carrying assistance with the -14 string on December 8,
1965. It experienced also operated the particular stretched DC-9-30 along with the MD-82.
III
The 1,000th MD-80 had been delivered on March 29, 92, and by December regarding 1997, 1,one
hundred fifty of the type ended up in service with 58 worldwide airlines. The style, partially succeeded
simply by its advanced, re-engined MD-90 counterpart as well as Boeing's own next Generation 737
household after that manufacturer's purchase of McDonnell-Douglas, nevertheless grew to become
its best-selling pure-jet commercial airliner, going above sales of the DC-8, the Super DC-8, the DC-9
by itself, the DC-10, the MD-11, the MD-90, and the MD-95/717, the past delivery of which got
occurred on december 21, 1999, any time an MD-83 had been handed over to TWA, ending two
decades involving production. Combined with the 976 sales of the unique, short-fuselage DC-9, it
became the third best-selling twin-jet after Boeing's 737 and Airbus Industrie's A-320 family, with a
collective two,167 airframes previously being built.
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