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Aviation History
1947
1947 - 0282.PDF
186 FLIGHT MARCH 6TH, 1947 MISSION TO INDIA ing blip can be read accurately enough when flying over water or over level ground, but it is inclined to alter its shape disconcertingly when flying over surfaces of varying height. Useful though it may be to know one's exact height above ground, the applications of the radar altimeter are concerned more with the hour-by-hour checking of baro- metric pre^ure against the readings of a normal altimeter on transoceanic flights and in the consequent obtainment The latest typ? ofminiaturized Gee equipment (right),with its lattice-line counters, shown bycomparison along- side the presentversion. of navigational assistance from pressure-pattern position lines. Gee is now sufficiently well known to make a descrip- tion unnecessary. Briefly, however, "blips" on two horizontal time-bases are lined up, and their relative posi- tions measured after series magnification. The resultant figures provide, with the help of a lattice-line chart, an exact fix in any area covered by Gee transmitting stations. Loran is merely a long-range version of Gee. The third of the navigational radar items mentioned, Rebecca, i- used in conjunction with Eureka responder beacons which have, during the war, been installed at many points in the world. The cathode-ray screen indication consists of a vertical time-base on which the position of a "blip'' ^ relation to a vertical scale provides an indication of th< distance of the aircraft from the beacon, wMe its position on the left or right of the time-base shows approximately how far the beacon is to the left or the right of the air- craft's heading. For blind-approach use Rebecca can work, of course, on a Babs beacon when greater local accuracy is required. Present Gee equipment has a weight of approximately 800 lb, but the latest miniaturized civil version is expected to have its weight reduced to rather less than 100 lb. The scanner window in this will be quite small and the chart- position figures will be directly recorded on counters as the lining-up adjustments are made. Eventually it k& hoped that a hyperbolic computer will be developed, ' with the help of which actual ranges and bearings may be read off without the need for lattice-lined charts. This last .is being developed largely for the benefit of pilots of single-seater aircraft. For these-pilots, too, a light- weight navigation computer is being produced as a de- velopment of the Automatic Position Indicator. The A.P.I, can be considered to be a logical extension of the Air Mileage Unit. In the latter the air pressure from the pitot head is directly balanced against an arti- ficial pressure produced by a motor-driven fan, so that the average speed of the motor provides either the true air- speed at any height within reason, or, if required, the, true air mileage. The air mileage is fed into the Position In- dicator, which is also '' ruled'' by the varying compass headings, with the result that, by means quite beyond my powers of imagination, the latitude and longitude appear as definite figures on a pair of counters. The readings of these counters are periodically re-set manually when definite visual or other fixes are obtained, so that the result at any particular moment is accurate enough for normal navigational purposes. In due course, no doubt, drift effects w^ll also be fed into the A.P.I, and the navigator will then become merely a machine-minder so long as the equipment continues to function. (To be continued) DEATH OF C. P. ROBERTSON WITH the death, on February 15th, of C. P. Robertson,O.B.E., Deputy-Director of Public Relations at the Air Ministry, the Press has lost a good friend and a kindly adviser.We on Flight had very close contacts with him right from the time of his appointment to the post of head of the Air MinistryNews Section as an officer in 1918, and in the course of the years '' Robbie '' accumulated an intimateknowledge of the workings of the Air Ministry and R.A.F. which was ofgreat value. It was "Robbie" who, in 1938, pre-pared the plan for an extensive Service P.K.O. organization which was put intooperation on the outbreak of war and thus forged a link between the R.A.F.and the public, a link which, whatever may have been its shortcomings in in-dividual cases, was of considerable value in letting the public know,through its Press, as much about the air war as could safely be told. Charles Pennycook Robertson wasborn in Argyllshire in 1889. After a short period in the Civil Service heentered journalism, holding many responsible posts until he joined the Lovat Scouts in 1916. The following year he transferred tothe Royal Flying Corps aud became a pilot. In 1918 he was as already mentioned, appointed head of the Air Ministry NewsSection, and when the post became a civilian one in 1919 he was appointed Press Officer. On the creation, in 1940, of theDirectorate of Public Relations, he was made Deputy-Director, C. P. Robertson,O.B.E. a post which he held until his death. He received the M.B.E.in 1929 and the O.B.E. in 1939. In spite of poor health for many years, C. P. Robertson attended to business if it washumanly possible, and it was this devotion to duty which took him from his bed to the committee meeting at which hecollapsed. Robertson leaves a widow, three sons and a daughter, towhom we extend our sincere sympathy. VICKERS' ANSWER TO ICING A S we go to press, details become available of extensive flying•^ tests in icing conditions made by Vickers-Armstrongs, Ltd., in co-operation with B.E.A. As a result of modifica-tions to the elevators, an increase in the flow of de-icing fluid and an extension of de-icing elements on the Viking, the A.K.B.on March 3rd approved the aircraft for service in all conditions of icing. With B.E.A.'s Captain Jones in command, accom-panied by Captain Summers, Vickers' chief test pilot, Mr./|, Edwards, chief designer, Mr. Cox and an A.R.B. represent?*live, Viking G-AHPG made in all twelve flights in severe iciS? conditions. Results showed that the modified T.K.S. system iseffective as an anti-icing and de-icing system, and that from the handling point of view the Viking is now very satisfactory, t Keen observers will notice differences in the elevators whichnow have a thickened chord at the trailing edge and have a larger horn balance on the starboard side than on the port.B.E.A. find that normal flying characteristics have been im- proved by the modifications, the elevators being slightly heavierbut more positive to handle. For the time being, one nacelle fuel tank will be sacrificed to carry G2 gallons of fluid, thusreducing fuel capacity to 692 gallons, which is still, however, plenty for B.E.A.'s present services. It is estimated that theVikings will be back in service in fair numbers by April 20th. Full details of the tests will be published next week.
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