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Aviation History
1950
1950 - 0535.PDF
FLIGHT, 16 March 1950 353 FOUR UP ... destination in fewer miles. A headwind might offset this advantage on some occasions. It is not such a simple matter to compare running costs for a car and an aircraft, because standards of require- ments are very different. Insurance depends upon many variables, although drivers' records and insurable values are considerations applicable to both. Because of the higher potential exposure, third-party cover is very much greater in the case of aircraft. Strangely enough, although third-party insurance is compulsory for a road-user, there is no law to compel a pilot to have any insurance at all. In practice, however, all aircraft are fully covered. To give some sort of indication of the cost of comprehensive insurance cover in each of the cases under consideration, a figure of ^25 per annum may be mentioned as representa- tive for the sports car and /105 per annum for the air- craft, for average private utilization of 20,000 miles (200 hr) per year. Maintenance costs, assuming both vehicles to receive; correct routine attention by qualified engineers, is another item difficult to compare. A car might cost 50s every 1,000 miles, plus one engine and chassis overhaul—de-coke, brakes, and so on—in 20,000 miles at a cost of ^20. This gives an annual cost of £jo. At least one set of four tyres would be required in this mileage, and these would cost about £16. Incidental repairs and adjustments would probably bring the total figure up to ^90 p.a. For the private aircraft the main annual servicing costs are for the renewal of the Certificate of Airworthiness and three 50-hour inspections. In addition, an occasional minor inspection and adjustment is desirable. The C. of A. for the first few years should not cost more than £bo on the average, and the 50-hour airframe inspections about £5 each. This makes a total of £75. Other minor inspec- tions of the D.I. type (say, one per month) would cost about 17s 6d each, and the supply of an occasional spare part would bring this figure to £15 ; thus the overall total again amounts to. about £go. However, some allowance must be made for engine overhaul, which in the case of the Gipsy Major would occur only every 7^ years, for it is a type which is officially approved for 1,500 hours' running between overhauls. This is a figure which will set most car engine designers thinking. If £10 p.a. is allowed for a share of the ultimate engine maintenance cost, the esti- mated figure for the Auster Autocar reaches £ioo p.a. The car engine would netd a major overhaul about twice as often as would the aircraft, i.e., every 60,000 miles. The cost would be, as a conservative estimate, and depending upon the number and configuration of cylinders, £80 to ^100. Thus, some £50 should be budgeted each yeai for this purpose. The owner-pilot pays £1 is registration fee, but the car owner pays ^10 annual registration. Major overhaul and registration of the car therefore offset some ^29 of the excess accommodation fees of the aircraft, re- ferred to below. • It is not proposed to discuss depreciation, but a mention may be made of housing and parking, and here the air- craft is almost always at a disadvantage unless the owner happens to be a farmer—as is not infrequent in the case of Austers—with a good barn and meadow available. A light aircraft costs at least £1 per week for hangarage, and land- ing fees vary between free and 7s 6d for the weight of machine in mind. Season landing tickets are available for groups of home airfields at £5 p.a. each (two would cover most needs). Incidentally, Service or ex-Service pilots may land a private aircraft free of charge at R.A.F. air- fields so long as prior permission has been obtained. For the hangarage cost a pilot should receive considerably more free service and facilities than would be expected from a garage. Flying control, navigation and met. services are available free of charge. In addition, one's aircraft is pushed out, started up and the engine warmed and checked in answer to a preliminary telephone call. In large cities, and in particular in London, the garaging of a high-powered car may cost as much as £1 a week, while in the country it may be as little as 5s. There is a similar though not so pronounced difference in costs for aircraft housing, hangars at main airports generally being more expensive than those on small and remote airfields. It may be mentioned in passing that landing and housing fees abroad, particularly in France, tend to be considerably lower than in this country. The foregoing discussion is not intended to put a case for owning an aircraft instead of a car, for the two are complementary forms of transport. Rather is it intended to indicate the remarkable similarity in cost and, to some extent, performance of the two. For those fortunate enough to be in a position to consider the ownership of two cars, or for the quite large number of people who have the use of car in connection with their business, the possi- bility of owning a light aircraft rather than a second (sports) car is worth serious consideration. M. J. A CAS TURBINE on the ROAD Convincing Preliminary Demonstration of the Experimental Rover Car BRIEF references have appeared from time to time in Fliglitregarding progress being made with the adaptation of gas turbines for road vehicles, and in G. Geoffrey Smith's book, Gas Turbines and Jet Propulsion, an informative chapter is devoted to the subject. Readers will since have learned with special interest of the demonstration given last week at Silver- stone of the turbine-engined Rover car, the first in the world to reach practical realization. It is particularly appropriate that the Rover Company should have had this honour, for during the war they Were responsible for the development of the early Whittle units, and in conjunction with Joseph Lucas, Ltd., designed the " straight-through " combustion system to replace the original "reverse-flow" layout. On Wednesday of last week, under R.A.C. observation, the car exceeded 85 m.p.h. on Lindley Airfield, near Nuneaton. Next day at Silverstone, it gave another impressive perform- ance. A Flight observer who was present can testify that the characteristic turbine whine was not nearly so marked as in aircraft and was, in fact, noticeable only when the power unit was sharply accelerated. Neither heat nor smell—the efflux is directed upways from vents behind the "cockpit"—were objectionably marked, and starting from cold was quick and certain. The car was ready to move off about T5 sec after the starter was switched on. In an article in The Autocar last week it was stated that the power unit is of the two-shaft type. The first-stage turbine drives the air compressor alone, whilst the second-stage turbine—mechanically independent—transmits power through reduction gearing to a conventional rear axle. This arrange-ment gives, in effect, a pneumatic torque-conversion system and therefore no clutch or gear box is necessary or is fitted ;the only two driving controls are the accelerator and brake. Designed to run at a speed of 40,000 r.p.m., the unit has sofar been run at 35-36,000 r.p.m. on test; it idles at approxi- mately 7,000 r.p.m. Fuel-consumption figures at the momentappear inordinately high by road-vehicle standards, but it must be remembered that the production unit, when it eventuallyappears, will be considerably smaller and will be equipped with a heat-exchanger, which will improve the thermal efficiencyand effect a considerable economy. Impressions of driving the Rover turbocar, by G. GeoffreySmith, together with an account of the two tests, will appear in to-morrow's issue of The Autocar. CONSULTANT'S APPOINTMENT A SPECIALIST in steam and gas-turbine design, Mr.E. P. Peregrine, B.Sc., Mem.A.S.M.E., A.M.I.C.E., A.M.I.Mech.E., A.M.I.E.E., has joined W. A. Turner, Jeffreyand Co., consulting engineers, as a third partner.. During the war he was engaged in gas-turbine research with Rolls-Royce,Ltd., and the Rover Co. In consequence of the appointment, the firm will be restyled Peregrine and Partners (incorporatingW. A. Turner, Jeffrey and Co.); their offices are at the Manoi House, Royston, Hefts. (Roysori 3213.)
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