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Aviation History
1953
1953 - 0104.PDF
102 FLIGHT, 23 January 1953 U.S. CIVIL HELICOPTER OPERATION... sacrificing load, speed or range. (In this connection, Piasecki have announced that they are, at the request of the U.S. Army, design ing a cheaper and simplified version of their H-21, and have managed to save some 1,300 lb on an aircraft of 8,400 lb.) Table I gives some specifications of the helicopters that the consultants think may be available during the above period:— To this list is added a note of optimism, besides a note of warning:— ". . . Direct aircraft operating costs per passenger mile will depend on average passenger loads which are expected to range between 60 and 70 per cent after the initial years of traffic development. A 70 per cent load factor will result in direct aircraft operating costs per passenger mile of 5 cents, while a 60 per cent load factor will yield costs of 5.8 cents per passenger mile. At a 65 per cent load factor, which is a reasonable traffic expectancy, direct aircraft operating costs of 5.4 cents per passenger mile will be realized. "In addition to design simplification leading toward cost reduction, the problem of noise reduction will, in all probability, confront both manufacturer and operator. Public dislike of 'aviation noise' now asso ciated with fixed-wing operations is not likely to diminish in the near future, but rather may be a controlling consideration from the outset. Because of its relatively slow air speed and with the need to operate much of the time at low altitudes, planning must take account of growing public antipathy to aircraft noise. Unless adequate research achieves a reduction of helicopter noise, operations may be seriously restricted into and out of the congested business centres of large cities. This would modify the pattern of helicopter service contemplated in this report. . . .'> Then follows a further warning that, because of the lower speed of the helicopter and because it will probably always pay a weight penalty as well (as a result of its ability to take off from, and land on, small areas) its direct operating costs can never be comparable with those of fixed-wing aircraft. In this connection, the report places the speed limit of helicopters (but not convertiplanes) at some 150 m.p.h. The estimated fares in cents per passenger mile, are forecast as follows:— Type of Service 1953-55 *955-56 1960-65 19^5-75 Aerocab* 40-50 30-40 25-30 20-25 Intercity — 12-13 9"10 6-5-7-5 Suburban — 11-13 8-10 * Airport shuttle service. The section of the report which deals with future regulations for helicopter operations makes the usual plea that the type should be judged on its own performance and capabilities—and limitations— rather than that attempts should be made to tie its regulatory pro cedures to those needed for fixed-wing aircraft. That the helicop ter will suffer from "fixed-wing thinking" is a constant source of worry to the rotating-wind protagonists here, though so far it does seem that the Civil Aeronautics Board and Civil Aeronautics Administration have both been quite open-minded on the question. The real troubles will come, of course, as a result of overcrowding, as helicopters will add yet another airborne vehicle to the already saturated atmosphere which exists around the larger American cities. The report adds:— "The development of helicopters capable of tapping the short-haul potential could conceivably be delayed many years if performance requirements and operating standards based on experience with fixed- wing aircraft are applied to the helicopter without due regard for its unique capabilities which cannot be duplicated by fixed-wing aircraft. The revisions of the three sections of the Civil Air Regulations covering rotorcraft air worthiness, aircarrier operations, and air navigation are of special importance since they will determine whether the helicopter will be able to use centrally located landing areas, and thus fulfil its mission as a short-haul carrier. Well-considered regulations, arrived at by the federal government with the utmost wisdom and foresight, will be essential to ensure both the position of the helicopter in short-haul common carrier transportation and a high order of dependability and safety for such a service. . . ." The necessity of fully dependable instrument operation is also stressed, and there is a plea for understanding, and imagination, in the field of airworthiness requirements. It is pointed out that the former requirement is essential, as it would not be feasible to have any system of alternate airports in short-haul operations around a city. The section of the report dealing with traffic statistics is chiefly of domestic interest, being based on the geographic and particular situation which arises around New York, with its three main terminal airports and its highly congested streets and exits from Manhattan Island, and big "dormitory" areas to the north and east. But there is no mention of the exceptional situations that may arise in flying into New York in very windy weather. Anyone who works in the city knows of the remarkable conditions of turbulence that exist around the higher buildings, and it seems quite likely that these gusts might, on certain days, be so bad as to preclude helicopter operation within certain areas (and chiefly those of greatest importance from a traffic point of view). There is also a chapter dealing with the routes and airways around the Greater New York region, and this again is largely of domestic interest, but it is followed by some data on airstop design , —a section which again impresses the importance of avoiding noise complaints. In discussing the actual areas to be used, the report stresses that adequate utilization can be achieved only if the : loading and unloading operation is highly efficient, and says that rotor blades must be automatically folded and movement of the aircraft about the airstop will probably have to be done by some form of floor-level tow-cables. It will be very difficult, if not : impossible, to supply servicing or parking areas at mid-town points ; owing to the high utilization and expense of the available space. Some of the suggested airstop design-criteria are as follows:— Space and Weight.—(a) Landing/take-off area, 20oftX 200ft; one 1 landing and one take-off platform, (b) Wheel loading, 19,000 lb. (c) Loading/unloading area, 30ft x 90ft; 8-17 loading positions. Id) Weight to be carried by each loading/unloading unit, 25,000 lb; 30-place helicopters are anticipated, but the weight would have to be increased by 50 per cent when 40-place equipment became available. Obstruction (Major and Secondary Airstops).—(a) Desired maximum elevation of operational area above street level, 100ft. (b) Minimum lateral-obstruction clearance, 100ft. (c) Minimum approach-obstruction clearance (from end of landing platform, plus 100ft), 35 deg. (d) Desired minimum width of approach and departure path, 500ft. As to the aircraft now in production or in advanced stages of design, a dozen are listed:— TABLE II. TYPES IN OR NEAR PRODUCTION Model Designation Commercial K-5 47D-1 360 S-52 S-51 48 S-55 PD-22 H-40 Military K-225 /H-13D \ HTL-4 JH-23A \ HTE-1 H-18 H-5 H-12 H-19 XHJD-1 H-21 No. of Seats 2 2 2 3 3 10 10 14 15 40 40 40 Payload (lb)* 341 495 516 522 1,179 1,728 1,784 2,600 3,623 8,000 9,801 17,664 Manufacturer Kaman Bell Hiller Sikorsky Sikorsky Bell Sikorsky McDonnell Piasecki Hiller * Computed for flight distances ranging between 51 and 100 miles. Note: Designation—s of last two types restricted by Department of Defence. Another table in the report gives, for the foregoing types, cost per available seat-mile (stages of 50-100 miles): K-5, $0,455; 47D-1, $0,344; 360, $0,091; S.52, $0,164; S.51, $0,203; 48, $0,350; S.55, $0,089; PD-22, $0,065; H-40 (preliminary design- study), $0,037. It is very difficult to condense such a mass of data as is contained in this report—and to British eyes it may indeed appear somewhat over-stuffed. But even if there is a good deal of it which could have been edited out, or reduced to more readable lengths it has, when boiled down, a great deal of meat in it. Maybe Ariel House is producing a similar survey for the United Kingdom, although Mr. Masefield's paper may, in effect, have done it for them. But in any case there appear to be several areas in which the New York picture overlaps Mr. Masefield's ideas, and between the two of them these two documents could form a blueprint for helicopter development for the next ten years or so. If the curtain of security which clouds development here were only to be lifted the print might be clearer, still. METROPOLITAN ROTORPLANES NOW that there is so much discussion of roof-top rotor-stations in London it is interesting to recall some experimental flights which took place as long ago as 1948. They were made at the instigation of Mr. L. F. Dyer, managing director of Metropolis Garages, Ltd., one of whose buildings, near Olympia, London, W.14, has a low, flat roof. On July 15th, 1948, an S-51, piloted by Alan Bristow of West- lands, made an accurate landing there on a small, marked area. The demonstration was arranged, in connection with the Mech anical Handling Exhibition, by the late Mr. G. Geoffrey Smith, editorial director of Flight. On April 27th, 1949, a similar landing was made at the Olympia garage by the same pilot. After a further demonstration flight, Col. Preston, of the Royal Aero Club, and Charles Gardner, of the B.B.C., were taken aboard and flown—with a re-fuelling stop en route—to Paris, thus com pleting the first flight from the centre of London to the centre of Paris. Other flights have been made into the heart of London, quite apart from B.E.A.'s recent proving trips. For instance, Mr. Lind- gren, at the time Parliamentary Secretary to the M.C.A., landed in St. James's Park from an S-51 in 1947, and another flight was made from a clearing near St. Paul's. At least one building has already been erected with a roof designed from the start for helicopter operations.
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