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Aviation History
1953
1953 - 0129.PDF
FLIGHT, 23 January 1953 COMMERCIAL-HELICOPTER ECONOMICS . . . 200mpih. 150m.p.h. »250mp.h. 175mp.h. OOmpA '^*200m.p.h. •OOmph. ^.-'j-SOOmph. IOO 200 300 . 400 500 INTERCITY MILES 600 700 Fig. 3. Travel time between city centres, for aeroplane (dotted) and helicopter (solid line), at various cruising speeds. From calculations by Piasecki and Wigdortchik (Ref. 10). medium and long distance airline services, but the rotorplanes would not normally be used for city centre/airport journeys. Over very short distances they would prove extremely uneconomic, although time-saving, compared with surface transport. Economic Prospects.—A guide to the probable expenditure involved in a transport helicopter development programme is given in Masefield's recent paper (Ref. n), and refers to the £50,000 "Bealine Bus". The cost of manufacture of two prototypes and one pre-production machine, engine and transmission development, ground and flight testing, comes to £4,500,000. Assuming £1,500,000 jigging and tooling costs, and £3 per lb of gross weight for direct labour and material costs, and overheads on production aircraft, the resultant cost (necessary to cover all development costs) would be £210,000 per aircraft for a production order of IOO machines, or £180,000 each for an order of 200. These prime costs are comparable on a weight basis to those for fixed-wing aircraft, but the minimum total capital outlay of £21,000,000— spread, incidentally, over some ten years—emphasizes the need for strong Governmental support if such a project is to succeed. This support, as mentioned, might well include development contracts for military versions of such a transport. Of even greater importance than prime cost to prospective helicopter operators is the question of operating costs. By 1955, it is estimated that the Bristol 173 Mk 3 could be operated at a total cost of 9£d per seat-mile over its most suitable stage length of 100 miles, compared with 6d per seat-mile for the Pionair over the same stage length today. The operating cost per seat-mile of the "Bealine Bus" remains fairly constant at about 6d for stage lengths of from 50 to 200 miles—a considerable improvement, and a figure that is unlikely to be bettered during the coming decade. Except for the very short stage lengths, the helicopter will be unable to equal or better the aeroplane's seat-mile costs (which approach 4d over the longer distances), but the increased speed and con venience of the rotorplane over distances up to 300 miles will counterbalance this. For example, on a 250-mile inter-city journey, the helicopter will save one hour over the fixed-wing aircraft and, more especially on the international routes of 200-300 miles, its fares will be no higher than those of first-class surface transport. Although standard methods of estimating the operating costs of Cost Item Direct coses:— Flying operations Direct Maintenance Fleet Depreciation ... Direct costs total Indirect costs:— Ground Operations ... Ground Installation ... Traffic, Passenger and Sales... Advertising General Administration Indirect costs total ———^— • Percentage of Total Operating Costs Aeroplane 26.2 14.5 9.2 49.9 14.3 9.1 16.5 2.5 7.7 50.1 Helicopter 33.0 18.2 9.5 60.7 14.8 4.7 8.9 2.8 8.1 39.3 127 fixed-wing aircraft cannot legitimately be automatically applied to helicopter figures, it appears that direct operating costs of the helicopter will be proportionately higher, and indirect costs lower, than those of fixed-wing aircraft. A recent analysis by Piasecki and Wigdortchik is shown in the table at the foot of column 1. Although the operational factors involved cannot be discussed at length here, the ones most directly affecting the economics of commercial helicopter use may be briefly mentioned. The cruising speed, payload capacity and ease of maintenance obviously depend on the basic design of the machine and should be as high as possible to reduce costs. Apart from the direct saving in time, a high cruising speed ensures high regularity and punctuality against head-winds, while on the maintenance side, planned replacement of parts after specified "lives" will reduce the time and expense of overhaul. For the very short routes, simpler standards of passenger accommodation would be acceptable, resulting in higher density seating and increased revenue. In the hands of the operator is the question of utilization : for economic operation this must be high, and indeed the helicopter itself is inherently capable of good performance in this respect. The B.E.A. scheduled services, both mail and passenger, were operated at an average annual utilization of less than 600 hours, with the obvious and uneconomic result; with increasing experi ence, a figure of 2,000 hours is to be aimed at. Turn-round times must be minimized to ensure the high frequency services necessary for short-haul traffic. Overall costs associated with rotorstations 4hr 3hr 2hr 1hr Estimated distribution of total operating costs for aeroplane and helicopter, assuming equal unit costs and productivity, over wu-zw mile stage-lengths. Source : Ref. 10. Fig. 4. Comparison of times taken and fares charged between helicopter, aeroplane and train over three important domestic routes. Fares assumed are : train, first-class return (1952); helicopter and aeroplane, estimated break-even return. Source : Ref. 11. will be lower than those of airports, and from the cost viewpoint (as well as from other important operational considerations) the use of roof sites on top of large buildings, which could house airline and other offices, is to be recommended. Such rotorstation sites will need to be developed at an early date. Immediately reflected in the operating costs will be the general and detailed operational techniques employed, which will define the design requirements, and as these techniques cannot be accurately selected without further operating experience, here lies the gseatest margin of doubt in any attempt to estimate future costs. Information is lacking on the actual problems experienced in regular multi-engine rotorplane services to and from city centre sites; and questions of fuel reserves, all-weather flight, air traffic control, navigation aids and rotorstation construction have yet to be answered with finality. In particular, a new conception of the diversion and stand-off fuel allowances needed is urgently required: the helicopter's ability to hover and to land in restricted places should enable lower allowances to be carried than for fixed-wing aircraft, with consequent increase in payload and improvement in economy. One further factor which could greatly assist operators in their attempts to operate helicopters economically would be the granting of mail contracts. For the job of transporting mail with speed and efficiency, the small or medium-sized helicopter has proved to be well suited, although operational problems connected with night- flying regularity remain to be solved, in view of the G.P.O. requirement for the transport of all helicopter mail by night. A more enlightened Government policy concerning helicopter mail, such as that of Belgium (see Ref. 9) could be of the greatest
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