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Aviation History
1954
1954 - 0695.PDF
EFFECTIVE SPEED OF TRANSPORTATION (kt) 400 STACE-LENCTH i.ooo 317 FLIGHT, 12 March 1954 Fig. 5 (left). Comparative costs in airline operation. Helicop ter types indicated in the num bered curves are (1) low so'idity, (2) high solidity, (3) low-solidity compound, (4) high-solidity compound. Fig. 6 (right). Comparative journey-time. Helicopter types indicated by the numbered curves are as in Fig. 5. 200 400 600 STAGE LENGTH fji.nO 800 \pOO DOMAIN OF THE HELICOPTER . . . situated in the centres of towns. The transit of passengers and luggage through these rotor-stations was assumed to be similar to that at railway stations with no advance booking, tickets being bought at the start of the journey. It was justifiable, he urged, to assume that helicopters would carry less fuel reserves than those for fixed-wing types: viz, supersonic aeroplanes, 0 miles for diversion plus J hr holding; subsonic aeroplane, 300 miles for diversion plus hr holding; helicopter, 20 miles for diversion plus J hr holding. Methods of computing direct costs corresponded closely to those proposed by B.E.A. and the S.B.A.C., both of which the author included as appendices to the paper. Typical airline costs had been computed from information supplied by B.E.A. The contracted and simplified operation possible from rotor-stations produced annual, hourly and landing costs for a typical 50,000 lb helicopter of respectively £40,000, £6.7 and £4.6 compared with costs of £45,000, £6.7 and £68 for a 50,000 lb aeroplane. Discussing the results of the comparison, the author said it was evident that for short-haul journeys the slow helicopters were much faster than the fast aeroplanes. A turboprop and subsonic aeroplane were in their element for journeys from 1,000 miles upwards. The convertible helicopter appeared to be capable of combining the advantages of the helicopter with those of the aeroplane. In terms of comparative journey cost the supersonic aeroplane was not competitive at any stage-length. The subsonic jet aeroplane could not compete with the turboprop aeroplane and the combined helicopter was notably better than the pure helicooter. The convertible helicopter had no rival between 200-530 mile stage-lengths. The factors of convenience and comfort, although economically imponderable, had significant economic factors. One of the most irritating experience in conventional air journeys was the change from coach to aircraft and then back to another coach. There was no doubt, the paper went on, that avoiding changing on a journey greatly enhances the comfort, apart from reducing the risk of lost luggage or similar mishaps. It was difficult to assess the value of comfort, but he personally would be prepared to pay the bus fare for the privilege of not having to use the bus. The lecturer went on to establish some of the many highly specialized duties for which helicopters were proving particularly suitable—such as cable-laying, pipeline surveying, fire fighting and flood rescue—and described what were the special reasons under lying the use of a helicopter in such roles. For example, the helicopter might make possible the saving of a few minutes in time which, in certain circumstances, might be of such value as to justify the operating costs incurred; or it might be that ground facilities were such that no other means of transport could be found to undertake a particular job. Summing-up, it might be recalled that, although the rotary- wing aircraft had originally appeared to offer more promise than had the fixed wing; the relative simplicity of the latter type of aircraft had caused it to be the first to reach fruition, at the expense of other lines of development. Now, the rotary wing was once more of general aeronautical interest, and it appeared likely that various forms of helicopter would eventually handle the vast volume of traffic on journeys of up to 500 miles. On short-haul work the helicopter was supreme, and the con vertible helicopter could successfully challenge the fixed-wing airliner on stages up to about 530 miles. On a city-centre to city-centre basis, the convertible aircraft was effectively faster than an aircraft cruising at Mach 2; in fact, there did not appear to be economic justification for the supersonic transport at any stage length. High speed transport would probably be achieved only outside the earth's atmosphere; until such developments material ized, the author concluded, we might expect a reasonable span of time during which we might apply some of our thoughts and energies to the helicopter; the rotating wing was revolutionary in the fullest sense of the word, and it demanded an imaginative and uninhibited approach. Fig. 7. Typical twin-rotor layout for short-haul journeys. WEIGHT BREAKDOWN (lb):— Equipped airframe Blades Hubs and transmission ... Power plant Crew Disposable load ... All-up weight SPECIFIC COST (Cllb):— Equipped Airframe ... Blades Hubs and transmission Power plant Complete aircraft FIRST COST (£):— Equipped airframe Blades Hubs and transmission Power plant Total cost NOTI Pure Helicopter (Low Solidity)(High Solidity) 12,916 1,560 5,025 6,523 554 23,422 50,000 10.0 15.0 5.0 10.0 9.33 129,160 23,400 25.125 65.230 242,915 •S: Assumed pro 12,899 2,520 5,200 6,523 554 22,304 50,000 10.0 15.0 5.0 10.0 9.50 128,990 37,800 26,000 65.230 258,020 duction: 100 off. Compound Helicopter (Low Solidity)(High Solidity) 14,912 1,260 4,250 6,523 554 22,501 50,000 10.0 15.0 5.0 10.0 9.45 149.120 18.900 21,250 65,230 254,500 Prototype and 14,601 1,735 4,490 6,523 554 22,097 50,000 10.0 15.0 5.0 10.0 9.50 146,010 26,000 22,450 65.230 259.690 levelopment cost Convertible Helicopter 15,178 1,210 2,282 16.533 554 14,143 50,000 10.0 15.0 5.0 10.0 9.87 151,780 18,150 11,410 165,330 346.670 s not included. Turboprop 19,290 640 740 7,613 554 21,163 50,000 10.0 15.0 5.0 10.0 10.0 192,900 9,600 3.700 76.130 282.330 •Machined skin. Subsonic Jet 18,170 0 0 7,870 554 23,406 50,000 10.0 10.0 10.0 181,700 0 0 78,700 260,400 Supersonic Jet 20,600 0 0 12,400 380 16,620 50.000 16.3* 1O0 14.37 336.000 0 0 124.000 460.000
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