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Aviation History
1953
1953 - 0462.PDF
45« FLIGHT THE DOUBLE-DECK PROVENC IN 1944 Societe d'Aviation Louis Breguet began studies for the design and construction of a large passenger-and/or freight-carrying aircraft. M. Breguet considered that the double-deck layout was the only practicable way of getting a large enough floor-area for the load envisaged, and that in the design of this type ease of loading and unloading was of the utmost importance. These studies produced the Breguet 761 No. 01, F-WFAM, which first flew on February 15th, 1949, was powered by four 1,580 h.p. S.N.E.C.M.A., 14R engines and which obtained its Certificate of Airworthiness at an all-up weight of 4.0 tonnes (88,185 !&)• During the early development of the 761, which was given the constructor's name Deux Ponts, Air France was not particularly interested in the type. The airline was in the difficult position of having to reorganize and rebuild following the war, and among its other problems was the costly introduction of a large fleet of new aircraft made up of Languedocs, DC-3S, DC-4S and Constellations. With its war-surplus engines, the original Breguet 761 did not appear sufficiently attractive. Three Breguet 761 "pre- series" aircraft were built, powered by surplus Pratt and Whitney R-2800-B31 engines developing 2,020 h.p. each for take-off and fitted with Hamilton Standard non-re versing airscrews. The first machine, F-WASK, success fully completed C. of A. trials at a weight of 45 metric tons (99,208 lb); No. 2 aircraft (F-WASL, later F-BASL) appeared in March, 1952, and it has completed 700 hr as a freighter with Air Algerie. As the design developed, the French Government subsidized the procurement of new engines, the aircraft became a worthwhile proposition and Air France began to show interest. Finally, in 1951, the airline placed an order for 12 type 763s, now known by the Air France designation Provence in keeping with the company's policy of naming French aircraft after French provinces. This latest version is powered by four Pratt and Whitney R-2800-CA18 engines, driving Hamilton Standard reversible- pitch airscrews of 13ft io.8in diameter, and delivering 2,100 h.p. for take-off (2,400 h.p. with water injection). The first Provence passed its C. of A. tests at a loaded weight of 48 metric tons (105,8221b) and it is planned to increase this to 50 metric tons (110,231 lb), at which all the I.C.A.O. requirements are met when using a runway of 5,247ft (1,600 m). Later the weight will probably be increased to 52 metric tons (114,640 lb). It has been found that a variation in camber throughout the span will obviate structural alterations to the wing as the weight is increased. This modification to the camber has been achieved, on the Provence now in service, by setting the inner sections of the flaps at 3 deg down, the outer sections neutral and the ailerons at 3* deg up. A total of 107 passengers can be carried in the Air France Provence : 59 tourist-class passengers on the upper deck and 48 second-class passengers on the lower deck. The second-class seating can be quickly removed and 6 to 10 metric tons (13,228-22,046 lb) of freight carried instead. Provences for Air France are registered F-BASN-V and F-BASX-Z, and numbered 1 to 12. F-BASN is being used for tests at Marignane in connection with raising the take-off weight to 52 metric tons. No. 2 aircraft, F-BASO, was flown to Le Bourget in August, 1952, beginning another series of tests, with Air France, on August 20th. These trials covered general handling in the air and included very thorough checks of engines and equipment under varying weather conditions and at various latitudes. Maintenance cycles were evolved and the schedules for each check prepared. As a start, first checks were made at 50 hr, (Left) While many of the 70 passengers explore the Provence, the captain keeps the big aircraft in trim. Below are glimpses of the upper and lower decks on the left, hostess Leys attending to the needs of passengers "upstairs"; stowed seats can be seen against the wall of the lower cabin (right).
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