AERIAL TOPDRESSING

Te Awamutu Courier, Volume 80, Issue 7152, 16 January 1950, Page 4

AERIAL TOPDRESSING

LARGE-SCALE TRIALS MADE COSTS OF OPERATING AIRCRAFT Large-scale trials have recently been carried out by the Ne.w Zealand Government to explore the possibilities of distributing superphosphate fertiliser from the air, says “The Pastoral Review and Graziers’ Record.” Results have been encouraging, but practical application of the scheme depends upon finding an aircraft capable of meeting exacting and varied lequirements. These requirements and the suitability of the Bristol Type 170 freighter aircraft for the task are examined in a brochure issued by the Bristol Aeroplane Company, Ltd. Assuming the radius of action to be 50 miles, the Bristol aircraft could, if fitted with internal hoppers of 309 cubic feet capacity, carry six tons of fertiliser (sufficient for 60 acres) and 150 gallons of fuel—enough for 50 per cent, reserve of range at cruising speed. It is thought that an allowance of a flying time of one hour a sortie is a reasonable basis for calculation. This would give a total of one and a half hours for each complete operation, allowing time for refuelling and reloading, delays and pilot briefing. At this frequency of operation the Freighter should be able to complete seven sorties a day, and cover 420 acres. As New Zealand authorities estimate that there are 120 flying days a year in the hill country, one Type 170 aircraft could treat 50,400 acres in a year. The immediate, target of 750,000 acres a year would therefore call for a fleet of 15 Freighters. Operating costs, calculated on the basis of 120 flying days a year, are estimated at £4l 14s 8d pe.r hour for the fleet of 15. Assuming a coverage cl 0 ) acres a sortie, the cost an acre would be 14s. If, however, the capital cost of the aircraft were borne by the Defence Budget—the aircraft ■would be operated by the R.N.Z.A.F. —the cost would be reduced to 8s 6d an acre. If maintenance costs were also borne by the Defence Budget, the cost would be further reduced to 4s lOd an acre.