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Aviation History
1959
1959 - 0454.PDF
fLIGHT, 13 February 1959 227' THIS article is a condensed version of a paper presented byiVir. R- C. Amsden, head of the applications section of the Fison organization's Chesterford Park research station, at the eighth NationalPower Farming Conference at Harrogate on February 11. The author has been concerned for some considerable time in the application ofsprays and fertilizer by helicopter, and in the development of spray-gear for fixed-wing aircraft. The conference was jointly organized by the twojournals "Practical Power Farming" and "Farmer and Stock-Breeder" Aircraft in Agriculture IN this country aircraft were first used experimentally inagriculture in 1947 for crop-spraying duties, and today thisis still their major use. The growth in the use of sprayaircraft is illustrated in the table below, the reasons for this increase including (1) development during and since the war ofmany new effective pesticides and weedkillers, (2) development of the helicopter, (3) availability of suitable surplus aircraft andspares after the war, (4) ever-increasing awareness of the farmer of the damage done to his soil and his crops by the use of heavyfarm equipment, and (5) the general trend towards larger farming units and in some areas larger fields. During 1957 and 1958 we had perhaps the worst outbreaks ofpotato blight of this century, and they coincided with exception- ally wet soil conditions—in fact the two circumstances were notentirely disconnected. The potatoes had to be sprayed with copper fungicide without delay, but for two or three weeks at atime the fields were often far too wet to stand the weight of a tractor and sprayer. Fortunately, there were more spray air-craft available than ever before, and it is estimated that at least 100,000 acres of potatoes were sprayed from the air in 1958 alone. U.K. crop acreages sprayed by Fison Pest Control aircraft Year 1950 1951 1952 1953 1954 Acres 9,738 15,083 31.299 29,521 13,893 Year 1955 1956 1957 1958 Acres 13,642 14,165 50,000 57,239 Note: From 1956 to 1958 the number of operators increased from one to eight. Total U.K. acreages for these /ears will be much higher than the one-company totals shown The availability of suitable fungicides was very nearly a limitingfactor in this huge campaign, but the men behind the machines —the pilots, the engineers, field and supervisory staff—wereworked right to the limit in the worst-affected areas. As a result, the spraying was done and the loss of crop was less than wasexpected. It is usually true to say that it takes one season's work to makea good pilot into a good spray pilot. A man who is flying a light aeroplane some 5-12ft above a crop at 40-80 m.p.h. has a full-time job just flying. He is all the time sensing air movements through the controls, listening to his engine, checking the airspeed, keeping one eye on fixed objects such as trees and over- head wires and the other eye open for moving objects such asbirds and other aircraft. These things are vital to his survival, and he has several important gauges—indicating spray pressure,tank contents, oil pressure, fuel level, etc.—to check at intervals. On every run he makes he has to fly straight over his flagmen,checking that they have not managed to get out of line. At the end of the run he has to shut off the spray with nice timing.In all this he must make due allowance for temporary changes of both wind-speed and direction, adjusting his height and posi-tion accordingly. In pulling up out of the crop he has to accelerate, climb over the trees and turn into wind—not banking too steeplyor the part-filled spray tank may take control of the aircraft. Then he must align his aircraft up.for the next run, throttle backand turn on the spray-cock just as he lowers himself down over the trees. The trees may be 150ft high, the crop over 40ft tall,and the nearest open space a mile or two away. It is always dangerous to generalize about human beings, butit is often found that good spray pilots are very much indivi- dualists. Like all individualists they are not naturally good team-workers, and it can be a trying job organizing a team of pilots, engineers and ancillary staff on a new operation.There is no traditional or cut-and-dried method for planning aircraft operations. Each job brings up its own problems andeach terrain has its peculiar difficulties. Sometimes it is necessary to leave a pilot and engineer to carry on with routine sprayingin an isolated area a thousand miles from base. There they may be faced with unexpected changes in local conditions (political,agricultural or meteorological) requiring decisions of a most unusual nature and needing clear thinking. The men working on the ground have to be a good team.Whilst the aircraft is spraying, log sheets have to be filled in, refuelling requirements anticipated and spray chemical got ready.Filling has to be completed without mess or danger whilst the engine of the aircraft is running, and with helicopters it is usualto keep the time from touch-down to take-off below two minutes. Lubricants, fuel and refuelling equipment have to be keptscrupulously clean and accounted for, water supplies vetted and chemical stocks checked against acreage sprayed. Errors in appli-cation rates have to be checked and necessary adjustments made to the spray-gear from time to time. Blocked nozzles are lesscommon than on ground machines, but nevertheless do occur and have to be cleared. Any leaks, drips or serious accumula-tions of chemical on the aircraft fuselage or windscreen must be dealt with, and inquisitive children and stray cattle kept at a safedistance. Fire equipment and first aid must always be at the ready. Spraying times for ten-acre field (220 X 220 yd) Operation Average time per spray run Average time per turn Time flying to and fro landing site and field Time filling on ground Time for 11 spray runs Time for 11 turns Total time for 10 acres Percival E.P.9 sec 11.1 32.9 sec 360.0 350.0 122.1 361.9 21.7 min Tiger Moth sec 10.6 19.0 sec 350.0 200.0 116.6 209.0 14.6 min Hiller 12A sec 18.7 15.2 sec 125.0 120.0 205.7 167.2 10.3 min For each man licensed to fly it is necessary to have two menon the ground. If you also include markers and tanker drivers this figure is nearer four. In this country the work is highlyseasonal and requirements vary from year to year, but as a global operation the work carries on throughout the twelvemonth andmay also include fertilizer top-dressing, anti-mosquito and locust spraying, locust swarm spotting, survey work, carrying oil-drillingequipment and so on. In this country the work is mainly confined to crop spraying,but in time will undoubtedly include more and more fertilizer application, slug baiting, seed sowing, and possibly even straighthaulage jobs in inaccessible places, e.g., dropping fencing materials on mountain pastures. Freight and passenger work in isolateddistricts and fire spotting and fire fighting are other possibilities, and in very adverse winters, of course, aircraft are already usedfor dropping fodder to farm animals. The economics of agricultural spraying from the ground orby air are very difficult to assess. The cost of chemicals used by both methods is, of course, the same per acre, but the aerial con-tractor uses about ten times as much chemical per hour as would a ground applicator, so he may be able to purchase his chemicalat an advantageous price. It is sufficient to say here that usually contract prices for aircraft spraying are about 50 per cent higherthan for ground spraying. Usually a sliding scale of charges is made so that areas under ten acres may cost about 20 per centmore than areas over 200 acres, but reductions may be made in cases where two or three treatments are necessary. For the farmer to pay this extra price willingly aircraft sprayinghas to have a number of advantages over ground spraying. The
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