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item Hoffmann, Wesley

Submitted to: American Society of Agricultural Engineers
Publication Type: Proceedings
Publication Acceptance Date: 12/13/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Aerial applicators must consider meteorological conditions, equipment selection and operation, and physical properties of spray solutions to increase effectiveness of the applied material and to decrease any effects on non-target locations. Drift or off-target movement of the applied material is influenced by turbulent air currents generated by the aircraft. .Turbulent air currents, which develop near the wingtips, can carry small spray droplets away from the intended target area. Vertical winglets located at the outer edge of the wing have been added to some agricultural aircraft in order to reduce the strength of turbulent air currents near the wingtips. Studies revealed that the winglets increased the swath width by 12.4 percent. The winglets also reduced the amount of sprayed material that drifted crosswind beyond the swath width by 38 percent. The results from this preliminary study show that further testing of the winglets under ra varying set of application and meteorological conditions is warranted. This information will allow aerial applicators to make informed choices when selecting application equipment.

Technical Abstract: Numerous researchers have reported that various modifications to the wingtips of agricultural aircraft reduce the vortex strength and the amount of spray material that drifts. Vertical winglets placed at the end of each wing are currently available to aerial applicators. Studies were initiated to determine how the winglets affect swath width and drift of spray applications by an Air Tractor 402B aircraft. The swath width and resulting deposition characteristics were determined by operating the aircraft with and without the winglets over a swath analysis system. While there were no statistical differences between the two treatments, the winglets numerically increased the effective swath width by 12.4 percent. The winglets also reduced the percent of small droplets deposited at the edges of the swath. The drift characteristics were quantified by measuring the movement of the applied material from 10 to 310 m downwind of the application site. There were no significant differences in drift for treatments with or without the winglets; however, the winglets reduced the deposition at the edge of the crosswind swath by 38 percent. There was also no significant difference between treatments if the left or right wing was upwind during the applications.