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Aviation History
1942
1942 - 1861.PDF
SEPTEMBER 3RD, 1942 FLIGHT • 263 DEVELOPMENT OF THE VS-300 HELICOPTER stantially constant number of revolutions per minute without the need ot manually adjusting the throttle; and (2) progressively throughout the cycle of rotation so that each blade will follow a varying path in relation to normal; this is controlled by the conventional control stick which not only determines tl\e direction ot inclination of the main rotor disc but also the degree of this inclination. Thus it is possible in a given condition of flight to have, for example, 9 deg. of incidence on the main rotor blades through action of the main pitch control and then to add or subtract a few degrees at any point in the cycle through action of the sectional control. The sectional control, of course, always works so that the lowest point of the blades in their cycle of rotation is at 180 deg. to the highest point. In conjunction with the investigation of the three fun damental controls outlined herein, the effect of fuselage covering in various degrees was also studied. Vertical fin area toward the tail of the fuselage was first applied as in Fi^/i; thereafter, the entire side of the fuselage was OTreYed as in Fig. 2 ; and, finally, a nose covering was mated to give a pay load of seventeen tons at 3,000 miles, twelve and a half tons at 4,000 miles, eight and a half tons at 5,000 miles. On a 3,000-mile haul one hundred of them could do the work of 280 of the present C-54S and 880 of the C-47S. In going to bigger, more efficient aircraft, we shall gain in many directions: in the output of ton-miles with respect to the weight of materials invested in the air craft; in the ratio of flight crew to tonnage moved ; and, finally, in the ratio of ground installations to work done in the air. Two other potentials of the current cargo programme should be kept in mind: gliders and aircraft built of non- critical material. Curtiss-Wright, sub-contracting into the woodworking industry, is building a 30,000-pound plastic- • wood aircraft. This craft is expected to have a 600-mile range with six tons at 175 miles per hour. Budd has large orders for a stainless-steel job of about the same weight and range, but reduced pay load. As both are experimen tal, airmen regard them with caution. Substitution pays no dividends where neavier materials cut into pay load. As for gliders, a good deal of nonsense has been written about them. The Army has hundreds on order, ranging ~>from two-place trainers to two ton cargo haulers. Their peculiar importance in cargo operations derives from the fact that an aircraft is theoretically able to tow approxi mately half its gross weight in a glider. Thus a 25.000- pound DC-3, with four tons in its own cabin, should he capable of pulling six and a quarter tons more in tow. although at greatly reduced speed. The enormous boost to the ton-mile output that the addition of a glider fleet would give to the prime carriers is obvious, but many problems relating to pick-up, crew relief on long flights, and glider behaviour in ice and storm conditions, remain to be solved. A two-ton glider is the heaviest now being built for the Army's cargo programme. Using Existing Aircraft The following operation, while based upon data pre pared by Pan-American engineers, is entirely hypothetical and has no relation to military movements, current or projected. It is simply a conservative estimate of what could be done with aircraft in existence, assuming reason- , able production quantities. if The bottleneck is the 2,000 mile ocean hop from Natal, on the Brazilian bulge, to certain landing areas on the West Coast of Africa. Suppose five Pan-American Boeing Clippers and eight Stratoliners were concentrated on that run. installed which provided an open cockpit for the pilot (Fig. 3). As a general rule it was found that £ certain amount of fin area made the controls considerably more effective and pleasant but that an excess tended to give too much damping to the action of the controls. The nose covering did not appear to change materially the flying characteristics, and the aircraft is being flown at present with this covering constantly installed. On the basis of the results achieved with the VS-300 helicopter during the year 1941 in which fundamental problems of control and stability appear to have been solved, the writer looks forward with confidence to the future of direct-lift aircraft. The future work that remains to be done will include the refinement of controls already investigated, as well as research along many other lines of thought. This will doubtless produce further improvement iu the handling qualities of the aircraft, but it is certain that 1941 has seen the VS-300 grow from an experimental laboratory model to an aircraft that embodies practical flying qualities. STAGE I All weights in pounds 5 Clippers 'at 4 round trips each per week =21,450 per day =150,000 per week 8 Stratoliners at 5 round trips each per week = 19,300 per day = i35,oooper week Total 40,750 per day= 285,000 per week Feeder aircraft required to move this weight from Miami to Natal: 2T DC-3S at 2.75 round , trips each per week =42,500 per day = 297,000 per week From west coast of Africa to Calcutta (via Cairo): 50 DC-3S at 1 round trip each per week , =40,750 per day = 285,000 per week STAGE II Three DC-4S, on through service from Miami to Calcutta, should be able to deliver 20.000 pounds a week = 950 pounds per aircraft pet day. Assume this type can he ndded to the service at the rate ot two a week, from August 1st, I942. By January 1st, 1943, 44 DC-4S would be available. 4< DC-4S would, therefore, land 42,000 pounds a day at Calcutta Stage I would meanwhile land 40,000 pounds a day at Calcutta Total 82,ooopoundsadayatCalcutt If to Khartoum instead: 44 DC-4S would land 83.600 pounds a day - Stage I would land 40.000 pounds a day Total .. .. 123,600 pounds a day STAGE III 1942-43 Assume DC-4S added at the date of one a day after January 1st, 1943. By July ist, 1943, 181 additional air craft would be available. As ot that date, they would be delivering caigo at the rate of: To Calcutta: 181 DC-4S =254,000 pounds per day Plus Stage I and 11= 82,000 pounds per day Total .. .. . .336,000 pounds per day By January 1st, 1944 : 365 DC-43 =429,000 pounds per day Plus Stage I and 11= 82,000 pounds per day Total .. .. 511,000 pounds per day Or to Khartoum: On July ist. 1943, Stage I, II and III = 467,600 pounds per day On June ist, 1944, Stage 1, II and III = 817,600 pounds per day WE MUST SHIP BY AIR (Continued from page 260)
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