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Lockheed had established a strong position in commercial
airliner production with its piston-engine Constellation series. Further development
brought turboprop engines to the Constellation airframe with
the Lockheed L-1249 Super Constellation.
In 1951, Lockheed was approached by Capital Airlines to
develop a new turboprop airliner which was designated the YC-130, however there
was no interest from any other carriers, so the design was dropped.
Subsequently, Capital Airlines went on to order 60 British Vickers
Viscounts. In 1954, as a result of American
Airlines' interest in developing a twin engine aircraft, the idea
resurfaced and the company offered a twin-engine design now designated the
CL-303. This newer design was a high-wing type and would allow for 60 to 70
passengers. This design was also shelved for lack of interest from other
carriers.
The following year, American Airlines revised its requirement
to a four-engine design for 75 passengers with 2,000 miles (3,200 km)
range. Lockheed proposed a new design, the CL-310 with a low wing and
four Rolls-Royce Darts or Napier Elands.
The CL-310 design met the American Airlines requirements, but failed to meet
those of another interested carrier, Eastern Air
Lines. Its requirements were for a longer range; a minimum cruising
speed of 350 miles per hour (560 km/h); and increased seating capacity to
the 85-to-90-passenger level. Lockheed redesigned the CL-310 to use
the Allison
501-D13, a civilian version of the T56 developed for the Lockheed C-130 Hercules military
transport. The airframe was stretched to allow for more seats and handle the
increased performance. This design was launched as the Model 188 with an order
for 35 by American Airlines on June 8, 1955. This was followed by Eastern Air
Lines with an order for 40 on September 27, 1955. The first aircraft took 26
months to complete and by that time Lockheed had orders for 129. The prototype,
a Model 188A, first flew on December 6, 1957, two months ahead of schedule. Lockheed
was awarded a type certificate by the Civil
Aeronautics Administration (CAA) on 22 August 1958. The first
delivery – to Eastern Air Lines – was on October 8, 1958, but it did not enter
service until January 12, 1959.
In 1957 the United States Navy issued a requirement
for an advanced maritime patrol aircraft. Lockheed
proposed a development of the Electra that was later placed into production as
the P-3 Orion, which saw much greater success — the Orion has been in continual
front-line service for more than 50 years.
The Model 188 Electra is a low-wing cantilever monoplane powered
by four wing-mounted Allison 501-D13 turboprops. It has a retractable tricycle landing gear and a conventional
tail. It has a cockpit crew of three and can carry 66 to 80
passengers in a mixed-class arrangement, although 98 could be carried in a
high-density layout. The first variant was the Model 188A, followed by the
longer-range 188C with room for 1,000 US gallons (3,800 L) more fuel
and maximum take-off weight 3,000 pounds
(1,400 kg) higher.
American Airlines was the launch
customer. Eastern Air Lines, Braniff
Airways and Northwest Airlines followed. The Electra
suffered a troubled start. Passengers of early aircraft complained of noise in
the cabin forward of the wings, caused by propeller resonance. Lockheed
redesigned the engine nacelles, tilting the engines upwards
three degrees. The changes were incorporated on the production line by
mid-1959 or as modification kits for the aircraft already built, and resulted
in improved performance and a better ride for passengers.
Three aircraft were lost in fatal accidents between February
1959 and March 1960. After the third crash, the FAA limited the Electra's speed
until the cause could be determined.
After an extensive investigation, two of the crashes (in
September 1959 and March 1960) were found to be caused by an engine mount
problem. The mounts were not strong enough to damp a phenomenon called
"whirl mode flutter" (analogous to the precession of a child's top as
it slows down) that affected the outboard engine nacelles. When the oscillation
was transmitted to the wings and the flutter frequency decreased to a point
where it was resonant with the outer wing panels
(at the same frequency, or harmonically related ones), violent up-and-down
oscillation increased until the wings would tear off.
The company implemented an expensive modification program (the
Lockheed Electra Achievement Program or LEAP) in which the engine mounts and
the wing structures supporting the mounts were strengthened, and some of the
wing skins were replaced with thicker material. All Electras were modified at
Lockheed's expense at the factory, the modifications taking 20 days for each
aircraft. The changes were incorporated in later aircraft as they were built. However,
the damage had been done, and the public lost confidence in the type. This and
the smaller jets that were being introduced eventually relegated Electras to
the smallest airlines. Production ended in 1961 after 170 had been built.
Losses to Lockheed have been estimated as high as $57 million, not counting an
additional $55 million in lawsuits. Electras continued to carry passengers
into the 1980s, but most now in use are freighters.
Several airlines in the US flew Electras, but the only European
airline to order the type from Lockheed was KLM which used twelve
between September 1959 and January 1969 in Europe and east to Saigon and Kuala
Lumpur.
In the South Pacific, Tasman Empire Airways Limited (TEAL)
and its successor Air New Zealand flew the Electra on
trans-Tasman flights. In Australia Trans Australia Airlines (TAA)
and Ansett each operated three Electras on
trunk routes between the Australian mainland state capital cities, and later
to Port Moresby, from 1959 until 1971. Ansett had
its three Electras converted to freighters in 1970–71 and continued to fly them
until 1984. Qantas also
operated four Electras on its routes to Hong Kong and Japan; to New Caledonia;
and to New Guinea (until the New Guinea route was
handed to Ansett and TAA); then later across the Indian Ocean to South Africa,
and across the Tasman in competition with TEAL after that airline became 100%
New Zealand-owned. The divestiture of TEAL's 50%-Australian shareholding was
itself prompted by the Electra order, as TEAL wanted jet aircraft, but was
forced by the Australian government to order Electras in order to standardise
with Qantas. Three Qantas Electras were retired in the mid-1960s and the fourth
in 1971.
Some Electras were sold to South American airlines, where the
Electra had highly successful operations, such as those of Lloyd Aéreo Boliviano and Líneas Aéreas Paraguayas; in both cases,
the Electra ensured the airlines' international operations before they started
using jets. Most notably, Brazilian flagship airline Varig operated
flawlessly a fleet of 14 Electras on the extremely busy Rio de Janeiro-São Paulo shuttle service (the
so-called Ponte Aérea - or "Air Bridge," in Portuguese) for
30 years, completing over half a million flights on the route before the type
was replaced by Boeing 737-300 and Fokker 100 jets
in 1992. The Electra became so iconic on that route that its retirement
caused a commotion in Brazil, with extensive press coverage and many special
tributes.
During the mid-1970s, several secondhand Electras were bought
by travel clubs, including Adventurers and Shillelaghs. Others were retired
from passenger service into air cargo use, 40 being modified by a subsidiary of
Lockheed from 1968 with one or two large doors in the left side of the fuselage
and a reinforced cabin floor. Air
California and Pacific Southwest Airlines were still
operating Electras for passenger service during the late 1970s into smaller
airports in the western United States.
In 1973, the Argentine Navy bought
three Electras equipped with cargo doors. These were used during the "Dirty War"
to toss political prisoners into the Rio de La Plata in
the infamous death flights. The Electras were also used for
transport duties during the Falklands War in
1982.
In 1983, after the retirement of its last SP-2H Neptune, the Argentine Navy bought further
civilian Electra airframes, modified several for maritime
patrol, and widely used them until their replacement by P-3s in
1994. One of the Argentine Navy's Electras, known locally as L-188E
Electron, is preserved at the Argentine Naval Aviation Museum (Museo de la
Aviación Naval) at Bahía Blanca.
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