Browsing by Author "Brown HA"

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    FEASIBILITY STUDY, EXTENDING THE SWATH WIDTH OF TOPDRESSING AIRCRAFT TO REDUCE STRIPING OF FERTILISER MIXES
    (Massey University, ) Brown HA; Grafton MCE; Davies CE; Currie, LD; Christensen, CL
    Fertiliser mixes of magnesium oxide coated urea and super phosphate require high application rates 250kg/ha - 500kg/ha. These rates are inclined to clog spreaders reducing their efficiency and compromising operational safety. As a result, the current spreader design is, not fitted for these rates. The swath width from a Cresco 08-600 without a spreader is only 12m wide, meaning many passes are required to cover a field. The mixture also tends to segregate which leads to striping. A new method of spreading fertilizer, which provides a wider swath width and an even distribution, is required. This method must be able to meet the CAA requirements for topdressing safety, minimise segregation in fertiliser mixtures and preferably should be applicable to most bulk fertilizers in common use; the method must not add any significant weight to the aircraft that would decrease its operating capacity. The feasibility of developing a means of initiating spreading of bulk fertilisers from topdressing aircraft hoppers from regions outside of the influence of the prop wash are investigated. If feasible, the system should be able to apply fertiliser across a 40m swath width at the target application rate, in a single pass. This would reduce flight time and improve the distribution pattern leading to reduced operating costs and higher crop yield. This preliminary report suggests that it is mathematically possible to widen the swath width of the Cresco 08-600 to 40m at an application rate of 350kg/ha by means of a screw conveyor transporting and evenly releasing fertiliser along the length of the wing up until the dihedral is reached. The next stage in this project will be to design the screw conveyor system and test it on the ground to see its limitations and potential safety concerns.