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Aviation History
1955
1955 - 1653.PDF
. 774 FLIGHT, 18 November 1955 NO / BUILDINGS / Hypothetical helicopter landing ground illustrated by the lecturer, showing building-height restrictions to permit a climb-away gradient of 1 in 10. In the shaded areas, buildings higher than those in the four take-off zones would be permitted, though there would still be restrictions; in the unshaded areas between the zones there would be no restrictions. The landing area would be approximately 400ft square, and each of the gradient "steps" would measure 100ft along the approach or take-off path. DESIGN OF HELICOPTER STATIONS . . . gradient were reduced to 1 in 6 the restricted building area wouldbe reduced to just under 20 acres. This made an appreciable difference to the cost of construction (Tables I and II) and it wasdoubtful whether many large cities in Great Britain could afford to reserve sufficient space in their central areas to accommodatesuch a ground level station if, indeed, any could. It would appear, therefore, that surface stations would be suitable only forsmaller towns except where there was a park near the business area of a large city which could be utilized for the purpose. One alternative for a large city, Mr. Hough continued, was theuse of a roof-top station which, in fact, had certain obvious advantages; the height reduced difficulty in siting, in relation toexisting high buildings, and drastically reduced the area of land affected by building height restrictions; the area of the site itselfcould be reduced, since terminal buildings and car-parking facili- ties could be incorporated under the landing strips; noise anddown-draught were further removed from the streets, and, finally, parts of the building could be used for other purposes so thatonly a portion of the site value would be attributable to the helicopter station. The only apparent disadvantage of the roof station was thatthe extra cost of providing and supporting a sufficiently strong roof slab might be so much more than the cost of the ground-level station as to outweigh its advantages. However, it was felt that the extra cost would probably be no more, and in somecases possibly less, than the cost of sterilizing, either wholly or partly, much valuable land in the climb planes of the ground-level station. The lecturer made no estimate of the actual con- struction cost, but the site value would be in the region of Table I: Cost of ground-level station away from the centre of a town where an average building height of 30ft may be expected. Site area No-buiidinqs area Buildings 20ft-30ft TOTALS Climb Plane 1 in 10 Sqyd 40,000 at 10s 18,000 at 10s 21 400 at 2s £ 20,000 9,000 2,140 £31,140 Climb Plane 1 in 6 Sqyd 40.000 at 105 6,100 at 10s 12,000 at 2s £ 20.000 3,050 1,200 £24,250 Table II: Cost of ground-level station in city centre where an average building height of 80ft would be allowed. Site area No-buildings area Buildings 30ft-80ft TOTALS Climb Plane 1 in 10 Sq yd 40,000 at if, 40.000 at £6 155.000 at £2 £ 240,000 240,000 310,000 £790,000 Climb Plane 1 in 6 Sqyd 40.000 at £6 1&.000 at £6 78.000 at 11 £ 240.000 108,000 156,000 £504,000 £72,000, assuming that only 50 per cent of the value wasattributable to the helicopter station. One important point had to be borne in mind in this respect; the large area of the roofwould reduce natural lighting and the building would, to some extent, be limited to such uses as warehousing and car parking.The use of a roof over a railway station or sidings might not be so economical, since the structure to support the landing areawould have little or no secondary use, but the possibility was worthy of consideration where the location and size of the railwaystation was suitable. Design requirements for a roof station would be similar tothose for the surface station, with the following main differences : passenger embarkation could be simplified by the use of shortstairways to embarkation points from the floor below; lifting arrangements from the street would be required for engine start-ing, refuelling and fire-fighting appliances (these could be either internal "goods" lifts or external hoists and they would also beused for lowering engines or fuselages of unserviceable heli- copters to road vehicles); special fuel pumping arrangementswould be needed; and a device to prevent helicopters over-running the strips also would have to be provided. The last-mentioneditem might take the form of short slopes, at the edges of the landing area, surmounted by kerbs. The structural design of a roof suitable for helicopter landingspresented a number of problems related to point loading and the isolation of the general structure from vibration or shock. Thedistributed load, of the order 10 lb/sq ft, did not offer any design difficulty and was well within the strength capabilities of modernsteel-framed buildings. Point load was another matter and, in the case of a 50,000 lb helicopter for example, the design of theroof beams and slab assumed a problem of magnitude. A project for small helicopters, involving the use of a tank and floating raftfor landing had been reported from the United States [illustrated in Flight of October 7th and it would be interesting to knowwhether it would be feasible and economic if applied to the case of heavy machines. Another interesting possibility was that, per-haps, modern methods of wing construction, as practised by aircraft constructors, might be applied to the roof superstructureto provide the necessary strength in a light metal design. There were several examples of roof-top landing sites in theUnited States and an outline scheme for such a station had been prepared for Liverpool. It was on a site in the centre of the cityreserved for a coach station and multi-storey car park. Its dimen- sions were 600ft in length with a maximum width of 290ft. Onelanding strip 400ft x 300ft could be provided, with waiting space for two large helicopters. A second alternative to the ground-level station was the use ofa floating platform for cities which had large stretches of water near their central districts. Design requirements would again besimilar to those for a surface station but the terminal buildings, etc., would probably best be situated on land. Floating stationswere well worth consideration by local authorities with suitable stretches of water.The lecturer concluded by suggesting that it would be most helpful if the Interdepartmental Helicopter Committee could pro-duce a second report in the near future with more specific guid- ance for local authorities as to when the helicopter might beexpected to have been developed into a safe, reliable and economic vehicle for inter-city passenger services. The committee mightalso determine suitable passenger capacities and flying require- ments for transport helicopters to be followed by aircraftconstructors and to be used by local authorities for the purpose of reserving sites and designing stations from which thesemachines could be operated. R.Ae.S. ASSOCIATE EXAMINATIONS TPHE Royal Aeronautical Society has issued the pass list for its••• Associate Fellowship examinations held last June, under both the old and the revised syllabus. Names of the successful candi-dates are as follows : — Part I.—F/Cdt. J. Armstrong, K. G. Balija (India), Sgt. A. Beedle,F/Cdt. T. J. Burns, R. Malet de Carteret (Canada), D. S. Carton, Tulsi Dass (India), R. F. M. Drake, F/Cdt. P. R. Evans, F/Cdt. M. Farmer,E. T. Harris, K. G. Hodson, G. A. Hopkoper (Holland), K. Kumar ("India), J. R. Lyon, G. G. Mahajani (India), A. A. Munday, F/Cdt.S. T. Newington, D. T. F. Ozanne, E. Roadnight, K. Sanjeevan (India), M. Shamarao (India), G. M. Turner. Part I (new syllabus).—V. Shirdher Hedge (India). Part II.—M. G. Cherry, F/Cdt. P. R. Evans, T. E. Fitzsimmons,D. Gill, M. J. Harris, S. M. Humphry, Capt. Milos Jelinek (Israel), M. V. Karve (India), K. R. Liversage, M. H. Lock, P. L. Manley,H. F. C. Newby, F/Cdt. S. T. Newington, R. A. Nicol, G. T. O'Brien, T. O'Brien, T. Opatowski, D. T. F. Ozanne, K. G. Page, T. S.Nagesha Rao (India), B. N. Vaman Rao (India), M. Shamarao (India), Sucha Singh (India), K. M. Smith, K. S. Subrahmanyam, D. H.Tipper, B. S. Ward. Part II (new syllabus).—L. A. Hall, N. W. Jones. .
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