FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Atlas
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1920
1920 - 0475.PDF
APRIL 29, 1920 j\ that at the present stage of development of the airship this is a most difficult subject, as although many notable flights have been carried out by our own and German rigid airships under War conditions, yet these flights have only proved that there are great possibilities in the airship for commercial purposes, and have not produced sufficient data to enable actual running costs under commercial conditions to be stated. Considerable experience, however, has been gained during the past three years which is sufficient to warrant certain conclusions, and on the assumption that these conclusions are correct, it will be possible to form some idea of the cost of this form of transport. I propose to consider an airship of 2,750,000 cub. ft., similar in size to airship R. 38 now building at Bedford in the Government airship dockyard. As I have previously pointed out, an airship of this size would be capable of carry- ing 15 tons for a journey of about 50 hours' duration at a continuous air speed of 60 m.p.h. I propose to assume that this airship would fly about 2,500 hours in the year, and on an average would make good a ground speed of only 45 m.p.h. (although I am personally confident that a ground speed of nearer 60 would be made good). This would make the yearly ground mileage covered about 112,500 miles, This amount of flying allows the airship to be laid up for three months in the year. From past experience it is considered that this amount of flying will be considerably exceeded by t airships operating on long-distance routes. The Cost of Airship Transport may be divided into :— (1) The cost of the airship. (2) The cost of the base. (3) Cost of operating the airship. (4) Cost of running the base. (1) The Cost of the Airship.—The War cost of an airship of 2,750,000 cub. ft. (R 38) is approximately £400,000, but this cost must not, I feel, be taken as a guide to the future cost of construction. To justify this statement I must point out, in the first place, that the airship industry is a compara- tively new industry. Progress in design was rapid and con- struction was slow, so that airships were obsolete long before they were completed. Standardisation of production was, therefore, impossible. Progress in design also led to altera- tions and improvements during construction, which, of course, meant delay and consequent increased cost. For these reasons, amongst others, airships in this country took any- thing between fifteen to twenty months to build, whereas in Germany, where development permitted a degree of stan- dardisation, airships of about 2,000,000 cub. ft. (R. 34 size) took onlv three to four months to build. I, therefore, feel, and I am not alone in the matter, that as soon as something approaching a regular airship construction trade is established the cost of a commercial airship similar in size to R. 38 will be under £200,000. 1 must also add that future airships will be of more rugged and simple construction than those built in the past, with the object of attaining low first cost, cheapness of maintenance and a longer life. I, therefore, propose to take the cost of such an airship at £200,000. (2) The Cost of the Base.—A commercial airship base will consist of housing sheds, gas plant, workshops (situated in the annexes to the sheds) for fabric workers, carpenters, en- gineers and allied trades. Landing rights over surrounding ground will be required, the extent of which will depend on local conditions. (I should mention here that any ground reasonably flat, the quality of the surface not being important, is suitable for landing.) The cost of establishing such a base with a shed to house two 2,750,000 cub. ft. airships, with all necessary equipment and plant, including a fair margin for such services as drainage, water supply, roads, but excluding cost of land, accommodation for station personnel or hotel for passengers, would be about £550,000 on present-day prices. I may point out in passing that housing sheds can easily be lengthened to meet develop- ment provided they can be built sufficiently high and wide in the first instance. A similar base, but with shed to house one ship, would cost £400,000. An~additional £25,000 would be required to erect and equip one mooring-mast at a base. A mooring station would consist 01 a moormg-mast com-' plete, gas plant, and small office and store accommodation. The size of the gas plant would depend on the amount the base is used, but a base with gas plant to produce sufficient gas for, say, two airships calling once a week would cost about £45,000 on present prices. The cost of the bases may appear high. It must be re- membered, however, that only about five bases will be sufficient to allow services to be run to all parts of the Empire. k • • • , \ • • Bases will gradually be increased in size, and extra sheds will become necessary ior repair purposes as traffic increases. An argument invariably produced against airships is the prohibitive cost of their bases. It is interesting, therefore, to take a wide glimpse into the future. Let us make, for example, a liberal estimate of the possible future airship requirements of the Empire, and assume that this is com- pletely met by a fleet Of, say. 120 airships. This enormous fleet, with the aid of mooring-masts, could be efficiently operated from five bases mentioned above, allowing for six sheds at each base. The capital outlay involved for these bases and attendant mooring-stations would be something in the neighbourhood of ten millions. To get the right perspective, one must compare this capital outlay to the hundreds of millions laid out in permanent ways for railways, and to the enormous sums expended in docks and harbours for shipping. (3) Cost of Operating the Airship.—-This may be divided into : 1, maintenance ; 2, depreciation ; 3, crew ; 4, gas ; 5, fuel. Before any idea of cost of maintenance and depreciation can be obtained, it is necessary to state the probable life of an airship and its parts. For this purpose the airship may be divided into : (i) fabric ; (ii) engines ; (iii) hull. With regard to fabric, this may be subdivided into : (a) outer cover ; (b) gasbags. Present experience enables the life of the outer cover to be placed at one year (2,500 hours flying), and that of the gasbags at 2J years. With regard to engines, owing to the fact that airship engines are not run at their full power except in emergencies, the life can be placed at 2,500 hours, or one year. With regard to the hull, the opinion of those best qualified to judge places the life at net less than five years. Tests of the duralumin of No. 9 rigid after three years' use showed no weakening whatever. The life of the hull I. therefore, propose to take as five years. (1) Maintenance.—Under this heading is included the necessary repairs and overhauls to the fabric, engines and hull, and replacement of fabric and engines during the life of the airship. The sum required under this heading is estimated at £40,000 per annum, or 20 per cent, of the first cost (£200,000), and this sum will be included in the operating costs. (2) depreciation.—Assuming a five years' life for the whole airship, a sum of £40,000 per annum will be required, which will enable the airship to be replaced at the end of its esti- mated life (five years), and this sum will be included in operating costs. (3) Crew.—Allowing salaries slightly in excess of those now paid for equivalent work on Service airships, the yearly cost of the crew would be £9,000. (4) Gas.—From experience during the War wi^h present- day methods of producing gas, assuming that the plant would be kept reasonably fully employed, the cost should not exceed 15s. per 1,000 cub. ft., which would be a net cost including maintenance and depreciation charges on the plant. The consumption of gas, assuming 2,500 hours (112,500 miles) flying per year, may be taken as 16,000,000 cub. ft., which would cost £12,000, or 2s. 2d. per mile made good over the ground. (5) Fuel.—Based on present-day contract prices for petrol and oil, the cost under this heading throughout a year may- be taken as 5s. bd. per mile made good over the ground. I may mention here that R. 34 in her Transatlantic flights averaged i-J gallons of petrol per mile made good. The above charges may be summarised as follows :•— (1) Airship maintenance (2) Airship depreciation (3) Flying crew (4) Gas . . , 5) Petrol and oil £ 40,000 40,000 9,000 . I2.OO0 3°,937 ' ~ • ^131,937 Or, on the yearly flying basis assumed, this would amount to 23s. 5d. per mile. (4) Cost of Running the Base.-—A description of a base has already been given, but the cost of running such a base must now be considered. 120 skilled men would be sufficient to run the gas plant and do all repairs to visiting airships; a further 50 unskilled workmen would be required for rough work. Allowing £5 per skilled and £3 per unskilled man per week, this would amount to a yearly charge of £39,000. I propose to allow a round sum of £12,000 for overhead charges (for such items as salaries, office expenses, etc.). 475
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
