ASABE Technical Library - Abstract

Abstract. A single particle ballistics model was used to predict the landing position of granular fertilizer when ejected from a fixed-wing agricultural aircraft. It considered the particle’s physical characteristics, aircraft properties, release point and velocity with respect to the aircraft, wind profile and propeller wash. Factors, such as the fertilizers’ particle size distributions and spreader design were also included in the Visual Basic model.

This paper attempts to validate this model on a Pacific Aerospace Cresco 600 aircraft for three products commonly spread in New Zealand: urea, di-ammonium phosphate (DAP) and single superphosphate (SSP).

Validation data of the lateral distribution was collected in two trials, where collector cones were placed in rows. A Cresco fitted with differential rate application technology capability flew over rows of collectors in order to record the distribution. Wind measurements were logged during the trials. Comparison of the model and trial results were dissimilar. The model’s initial output showed the distribution was skewed towards the left side of the plane. Some model inputs, such as discharge velocity, could not be measured but were found to have a significant impact on the model results. Several components, including discharge angle and wind, were adjusted to produce the desired result.