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Aviation History
1949
1949 - 1831.PDF
FLIGHT, 3 November 1949 595 Progress of the Princesses : . : trouble with reduction gears and no trouble was anticipated with the common gear boxes of the paired units. One reason for this, he pointed out, was the free-turbine design in which the gas-generator section was mechanically separate from the power turbine and airscrew drive. Secondary problems of development which still needed to be cleared up concerned labyrinth seals, combustion-chamber life and oil scavenging. Certain details of the air intakes had also to be settled. One of the results of faulty oil-sealing was the fouling by oil (and dust) of the compressor blades. As all compressors were extremely sensitive in the matter of blade profile and finish, the outcome was a reduction in efficiency. Proteus turboprops will fly first in a Lincoln test-bed ; the gas-producer section—a development turbojet known as the Phoebus—has already undergone extensive air test- ing inside the bomb bay of a Lancaster. Coupled units will not have been flight-tested before installation in the Princess boats. The Proteus was described in detail in Flight of August 18th. It first ran in January, 1947, and was specifically designed for commercial operation at 30,000-40,000^ and in aircraft capable of cruising between 300 and 400 m.p.h. Preliminary basic performance data are given in the table below. • Airscrew shaft h.p Jet thrust Spec, fuel consumption Compressor r.p.m Power turbine r.p.m. Sea level Static 3,200 800 0.688 lb/s.h,p,,'hr 10,000 10,700 350 m.p.h. at 35,000ft 1,260 560 0,510 lb/e.h,p./hr 10,000 10,700 INDIAN EXPRESS Latest Version of the Constellation for Air-India International N OTWITHSTANDING comparatively bad visibility overalmost the entire route, many of the larger cities ofNorthern England were afforded a glimpse of the first Lockheed Constellation, L-749A, to be flown in Britain whenAir-India International gave a two-hour demonstration flight last Friday, October 28th. Maratha Princess, as the aircrafthas been named, is equipped with 40 sleeperette-type seats and was commanded on Friday's flight by Capt. K. Bhore, thegeneral manager of Air-India and Air-India International. The flight was made at 2,000ft and at a low cruising speed of T75knots, so that spectators on the ground might easily view the aircraft. Conditions at London Airport at the end of the flightnecessitated a landing under G.C.A. control. The passengers —among whom was a member, of the staff of Flight—were im-pressed by the extremely efficient soundproofing of the main compartment and with the almost complete absence of vibrationthroughout the aircraft. The most noteworthy differences between the L-749A andprevious marks of Constellation are seen in the new design of the airscrew blades and the 5,000-lb increase in maximum take-off weight, of which 4,800 1b represents an increase in payload. The Curtiss Electric 830 airscrew blades permit the use oflower cruising r.p.m. and a greater range of engine-operating conditions. Although no definite improved performance figureshave as yet been announced, A.I.I, pilots state that the new airscrews have conferred better climb characteristics and animproved cruising speed at low altitudes, though they are of the opinion that the airscrews are slightly less efficient athigher altitudes. Greater fuel economy is also expected to be shown when operational data have been accumulated. Externally, the aircraft presents an even cleaner aspect than The fitting of Curtiss Electric 830 airscrew blades has led to increased performance at lower altitudes. u 13 The sleeperette-type seats in the Maratha Princess are designedto give a comfortable reclining position for long journeys. The leg-rest attachment can be seen. before, as the carburettor air intakes have now been fittedinside the N.A.C.A. cowlings, with a resultant decrease in para- sitic drag. The autopilot has been modified so that a steadycourse is now held by use of ailerons instead of rudder, and changes have also been made in the pressurization system topermit manual control of the aftercooler scoop, the auxiliary vent exit and the refrigerator by-pass valve. The refrigeratingequipment is now operable even when the aircraft is on the ground. Additionally, the radio officer's seat is now facing aftin order to give him a more advantageous position when operating his key. Safety Measure An increased degree of safety is provided by the installationof hold-inspection covers in the floors of the galley and main passenger compartment respectively; on removal of the coversa specially designed optical system presents an illuminated image of the complete baggage area of the aircraft, and anyoutbreak of fire or movement of the baggage stowed in the hold can thus be easily detected. Maratha Princess is being used to operate a weekly express service—the first flight of which took place last Sunday, Octo-ber 30th—between London and Bombay, with an intermediate stop at Cairo. The flights are being completed in 21 hr 35 minelapsed time, of which a total of 20 hr 5 min is spent in the air; the improved Constellation now permitting a full load tobe carried over the whole distance. Although it is the first of its kind to be flown in GreatBritain, the Maratha Princess is not the only L-749A operating on this side of the Atlantic, K.L.M. having recently put intoservice an aircraft of similar specification. Air-India Inter- national expect to take delivery of another L-749A early in1950.
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