Il Lockheed C-5 Galaxy è un quadrimotore turboventola da trasporto strategico ad ala alta prodotto dall'azienda statunitense Lockheed Corporation.
In service since the late sixties until today, the C-5 Galaxy is one of the world's largest military aircraft and in military field, is used exclusively by the United States Air Force.
The C-5, won a competition for a high-capacity transport aircraft and jet engines. Capable of over 100 tons of payload, was produced in two series, for a total of 131 specimens and had a similar nell'Antonov only An-124 Ruslan overcoming the An-22 Doors "Cock" who had just preceded . The load capacity was exceeded only finally by An-225 Mriya, the version of the Ruslan esareattore.
is currently being evaluated in a deeply updated version, the C-5M Super Galaxy that by converting the latest version of the Galaxy could complement the C-17 Globemaster III in operational service for the coming years.
Development
In 1961, several U.S. aerospace companies began to study the opportunity to realize a project of heavy jet transport aircraft to replace the Douglas C-133 CargoMaster service and integrate into the Lockheed C-141 Starlifter. In addition to higher overall performance the United States Army expressed the need to take advantage of a tactical transport aircraft that could have a larger cargo compartment of the interior of the C-141, now it is too small to carry many items of equipment. Various studies led to the project "CX-4, but in 1962 a proposed esamotore was rejected because it was thought to have evolved significantly in the C-141.
Since the end of 1963, the new draft rule was redesignated CX-X, and equipped with four engines instead of six in the original design. The CX-X had a weight load of 550,000 pounds (249,000 kg), the ability to carry a maximum load of 180 000 lb (81,600 kg) and can reach a speed of Mach 0.75 (500 mph, 805 km / h). The cargo was brought to 17.2 ft (5.24 m) wide by 13.5 ft (4.11 m) tall and 100 ft (30.5 m) long and features both access doors front and rear. In order to achieve the thrust and the autonomy necessary for the use of four engines was necessary to start designing a new engine that foase with considerable efficiency.
Heavy Logistics System
Eventually specifications were definitively established by determining, in April 1964, the issuance of request for the provision of a "Heavy Logistics System" (heavy logistics system) (symbol CX-HLS, previously CX-X). In May 1964 the proposals received were designed for the aircraft from Boeing, Douglas, General Dynamics, Lockheed and Martin Marietta, and the engine by General Electric, Curtiss-Wright Corporation and Pratt & Whitney. After an initial screening were entered into contracts with Boeing, Douglas and Lockheed to run an extra year to study the structure of the aircraft, and with General Electric and Pratt & Whitney for the engines.
All three projects had similar characteristics. In particular, all had chosen to place the well deck above the cargo area to prevent, in the event of an accident, the same could slip toward the front by pressing the crew. Proposals Boeing and Douglas employed a "pod", located at the top of the fuselage, which contained the cabin, while Lockheed extended the space reserved for the crew in an area along the upper section, giving a characteristic egg shape. All projects included the adoption of a wing and arrow to load the front and rear doors to be able to run simultaneously loading and unloading. To configure the dell'impennaggio Lockheed chose a pattern T and Boeing and Douglas maintained a more traditional.
The Air Force considered the draft better than Boeing and Lockheed, but the latter had the lowest offer price. Lockheed was chosen as the winner in September 1965 and was awarded the contract in December 1965. The engine design was selected by General Electric in August 1965.
series production
The first C-5A Galaxy (number 66-8303) rolled off the Lockheed-Georgia Company (Gelacio) of Marietta, Georgia, March 2, 1968 and June 20 after he was flown for the first time, with the call-sign "eight-three-oh-three heavy" (8303H), beginning the series of preliminary tests to verify the overall reliability in flight conditions. The increased costs and technical problems of the C-5A was the subject of a congressional investigation in 1968 and 1969 The Lockheed C-5 program is remembered for the characteristic of being the first program to generate an extra cost of a billion dollars.
Upon completion of the test series the first C-5A was transferred to the Transitional Training Unit at Altus Air Force Base, in Oklahoma in December 1969. Galaxy Lockheed then delivered the first operational capacity to 437th Airlift Wing, based at Charleston Air Force Base, South Carolina, in June 1970. Because of the development costs higher than expected in June of 1970 there were contacts between the government and the military structure to divide the losses that Lockheed was making. The production was almost zero in 1971, Lockheed was going because of financial difficulties, partly due to the C-5 Galaxy, but also the civilian liner, the Lockheed L-1011.
In the early seventies, the C-5 was proposed to NASA as a suitable aircraft to fill the Shuttle Carrier Aircraft role to transport the Space Shuttle at Kennedy Space Center, but was also preferred the Boeing 747 due to its low-wing configuration. On the contrary, the Soviet Union decided to use the same role the Antonov An-225 high-wing, derived from An-124, which was the correspondent of the Soviet-American C-5.
During the static tests and fatigue cracks occurred in the wings before the completion of test cycles. Therefore all C-5A was imposed a reduction to 80% of the maximum load required by the design specifications and to limit the value of wing loading were introduced for additional technical measures. Since 1980, the ability to charged during normal missions in non-war were confined to the 50 000 lb (23 000 kg). To restore the full payload capacity and operational life in 1976 was initiated a program to replace the wings in 76 specimens of C-5A. After the project, and tests on the new wing of the C-5A were updated to the new standard between 1980 and 1987.
the first C-5B was delivered to Altus Air Force Base in January 1986. In April 1989, the last of 50 C-5B was added to the 77 C-5A cargo already in the structure of the USAF tactical transport. The C-5B included all the improvements introduced in the C-5A as well as numerous changes to improve reliability and ease maintenance.
in 1998, was launched a program to recover the full operational capabilities of the C-5 and equipping of major updating, adding that the C-17 Globemaster III without having to burden the U.S. defense budget for the purchase of new aircraft. Although August 2009 was still under discussion in Congress about its real effectiveness, the program has generated a new variant of which was given the official designation C-5M Super Galaxy .
The program is divided into two stages, is made with the initial Avionics Modernization Program (AMP), with the aim to upgrade the avionics on C-5 by introducing a glass cockpit, a new navigation equipment and a new autopilot. A second program, called the Reliability Enhancement and Re-engining Program (RERP), is aimed at updating the propulsion system and increase the efficiency and reliability re-equipped airplanes with new engines that give increased thrust.
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