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Aviation History
1921
1921 - 0243.PDF
APRIL 7, 1921 vxmJ CAMBRIDGE UNIVERSITY AERONAUTICAL SOCIETY (OFFICIAL ORGAN "FLIGHT") ON March 9, 1921, a very interesting and instructive paperwas read by Sir Napier Shaw, Sc.D., F.R.S., F.R.Ae.S, entitled— The Artificial Control of Weather The lecturer referred to the extraordinary grip which thesubject of weather control had on the imagination of the ancients, and how it is constantly referred to in the Greekmythology, where Zeus controlled the thunder and his deputy, iEolus, the wind. Right down the times the subject hasoccupied the minds of men, and among the more common modern applications attempted are the precipitation of rainby gun fire, and the avoidance of hail by the dissipation of thunder clouds. The lecturer mentioned examples of thedesired effect having, apparently, been attained, but called attention to natural changes in the -weather which were dueabout the same time, and he left it to his audience to judge which was the more likely cause of the two. For the benefit of those who still adhere to the belief thatweather control is possible today, it may be stated that the distinguished weather expert admitted that many of theforms of control suggested are not impossible, any more than it is impossible to build a jetty 200 miles long for the purposeof diverting the Labrador Current, as was proposed some years ago. As the lecturer said, " There is nothing whichcan be called impossible in building a jetty 1 mile long, and a 200-mile jetty is only 200 times as long. It can only be aquestion of money, material and perseverance. But for prac- tical purposes impossibility is reached when the money andmaterial required exceed the limit of what is available, and it is from that point of view that all proposals for the humancontrol of the weather have to be viewed." One of the problems in weather control that would be ofthe greatest importance to aviation is the dispersal of fog. On this question the lecturer made the following statement,which we publish in full, as it may save those who are tackling the problem a great deal of valuable grey matter :— " It would appear from experience that the easiest way ofdisposing of the comparatively calm fogs of an aerodrome is to get up a slight wind and blow them away. CaptainCarpenter in his report on London fogs in 1902, found that valley fogs could not survive a second of wind at Kew beyond13 m.p.h. (Factor 3) ; the same process would not work for hill tops. Such a wind corresponds with a difference of pres-sure of a millibar in 75 nautical miles. A bank of air three metres high along one side of a quarter mile aerodrome wouldbe sufficient and it seems rather absurd to call the main- tenance of such a bank impossible. But it is so. " A more reasonable suggestion was made to me somemonths ago in a letter from a Flying-Officer. He had noticed that the players in a football match which he was watchingkept themselves clearly visible while the rest of the ground was befogged up to a thickness of about 30 yards. He supposedthat the air was dead calm, and spaces might therefore be permanently cleared by local heating. It is, however, anessential pecularity of fog that the air in which it floats is never really still, it always has a slow drift, as anyone can seewho watches a fog from the inside. In fact, if there were no drift there would be no fog problem. The drops would sink to the ground. Gravity would do the work of removing themin the simplest possible manner. It is only the eddy motion accompanying the drift that keeps the drops persistently inthe air by preventing them settling. Taking the drift at two miles an hour, I made a rough computation of the coalrequired to clear an aerodrome 400 yards wide. It worked out at about 12 tons an hour for coal consumption, for a50-feet fog, and ran up to 400 or 500 tons an hour as an outside figure to meet ordinary contingencies using electrical distribu-tion. Again it is simply a question of magnitude. 1 have myself no practical conception of the amount of combustionwhich is implied by 12 tons or 100 tons an hour. My sheet anchor about coal is that a fire in my college-room used abouttwo hundredweight in a week of about 100 hours, or about one thousandth of a ton per hour. So 12 tons per hour is theequivalent of 12,000 college-rooms. Shall we say five times the consumption of the University and Colleges of Cambridge ?Such an amount of combustion is hardly to be called impossible, but no other adjective is so nearly an expression of the facts. " If we approach the same problem by mechanical meansand endeavour to drive away the foggy air of an aerodrome by propellers capable of giving a speed of 100 kilometres perhour to the propelled stream we find ourselves in the same difficulty. We arrive at figures for which ' impossible 'is only too strong a word if you disregard all questions of cost and effort. " What it comes to then is that all the suggestions for thehuman control of weather oppress one, not always by mis- taken conception of physical processes, but by the ' scaleeffect.' Within our knowledge we are lords of every single specimen of the atmosphere which we can bottle up and im-prison in our laboratories, our furnace flues or our green- houses ; but in the open air the ordinary inexorable lawswhich control the behaviour of the atmosphere, when we are awake and when we are asleep, have such enormous quantitiesof energy in the form of warmth and water-vapour in reserve that our own little reserves are not equal to making anyserious impression on the course of nature. " Yet the course of the weather may be affected by whatmay be regarded as violent artificial means, such as the explosions of a great volcano. In a recent work by ProfessorW. J. Humphreys the suggestion has been put forward that cold summers and even glacial periods have been caused inthat way, and I see a prize is offered for an essay on the connection between vulcanism and storms, among otherthings. " So perhaps we might give a new turn to our thoughtsby exploring how far our reserves of available energy compare with the destruction of Pompeii, the disappearance of theisland of Krakatoa or the eruptions of Mt. Pelee and La Souffriere. In any case it is the law of conservation of energywhich we have to bear in mind, and it is the vastness of the volume and mass of the air affected which has hitherto offeredinsuperable obstacles to the application of known physical processes for the control of weather. Any new physicalprocess to be successful will have to arrange for a great economy in the energy required, or give us access to supplies of energywhich are not now available." Launch of " R. 36 "ON Friday, April 1, the " R. 36 " was launched at the Inchinnan works of Messrs. William Beardmore and Co., Ltd.Leaving Inchinnan at 3.15 p.m., the airship cruised about, paying a visit to Glasgow, and returned to her shed atInchinnan at 6.20 p.m., after a very successful maiden flight of close on three hours' duration. The " R. 36," or G.-F.A.A.F.to give her her civil registration mark, was designed in 1918 by the Admiralty, and is the first British airship to be adaptedfor commercial work. She has cabin accommodation for 50 passengers in a special cabin built on to the main structure. And Her Night Trip to PulharnAFTER her successful trial flight on Friday, the " R. 36 " left her shed at Inchinnan on the evening of Saturday, April2, for her station at Pulham, Norfolk. She -was brought out of her shed and cast off without a hitch, leaving Inchinnan at7-4° p.m. with a distinguished party on board, among whom were Lord Weir of Eastwood, General Weir, General Maitland,and General Brooke-Popham. After leaving Inchinnan, R- 36 " proceeded leisurely on her way to Pulham, her logfor the trip being as follows :—Dunbar, 9 p.m. ; Fame Island, 10 p.m. ; mouth of River Tyne, n p.m.; Flamborough Head, 1 a.m. (Sunday morning) ; Howden, 2 a.m. ; Skegness, 3 a.m. ; Hunstanton, 4 a.m. ; Mundesley, 6 a.m. ; Pulham, 12.52 p.m. It should be pointed out that no attempt was made at making a fast passage, the journey being completed in a leisurely fashion so as to make observations and get the ship " run in." On April 5 she left Pulham at 7.40 a.m. for a cruise, arriving over London about 9.30. After leaving London "R.36" was to proceed to the South Coast, and thence along the coast to Land's End. From there it was intended that she should turn north, going as far as Liver- pool, whence she was to cross eastwards to her base at Pulham. Owing to some minor adjustments being required the trip was not carried out, " R.36 " returning to Pulham at 9.10 p.m. Another Giant Aeroplane FROM Turin it is reported that another Italian constructor —this time Signor Ricci—is completing a huge machine. The Ricci, unlike the ill-fated Caproni, is stated to be a quadruplane, with a total horse-power of 5,000 and a wing area of 8,600 sq. ft. The machine is designed to carry 130 passengers, and the estimated speed is about 90 m.p.h. The useful load is given as 20 tons. 243
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