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Propeller wash effects on spray driftAuthor(s): Steven J. Thompson; Alvin R. Womac; Joseph Mulrooney; Sidney Deck
Source: In: The Society for engineering in agricultural, food, and biological systems, paper Number, AA05-007: 1-16
Publication Series: Miscellaneous Publication
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Descriptionfor aerial spray application, there is some question if off-target drift (both near and far) is influenced by which boom is spraying and the direction of propeller wash rotation. This information may be useful when switching off one boom close to a field boundary. The effect of alternate boom switching and propeller wash direction on aerial spray drift from a turbine-powered aircraft was investigated. Both high volume and alpha cellulose spray sampling sheets were placed at three sample lines to collect drift fallout 104, 134, 195, and 317 meters downwind, perpendicular to the flight path. An aqueous mixture of malathion was applied from the aircraft through fifty D6-46 hollow cone tips. Five total replications were conducted over two days. Each replication had four treatment combinations of boom switch (left or right, on or off) and airplane direction. Propeller was effects were surmised from boom selection and aircraft direction. Data from preliminary study served as a basis for refinement of analysis procedures. The present analysis introduced weather variables besides wind and adjusted downwind distances to account for wind direction. Results showed that neither active boom nor boom location (upwind or downwind) was statistically significant for either sampling method at 0.05 level. There was significant influence of horizontal sampler location for the Hi-Vol samplers (p=0.0347), and solar radiation was significant at the 0.01 level for both sampling methods (p=0.0043; p=0.0021, respectively). When analysis was limited to the second day of testing, propeller was direction was significant at the 0.10 level for the fallout sheets (p=0.0773), and at the 0.05 level for Hi-Vol samplers (P.0.0200). Graphical representation indicated that higher concentrations occurred when propeller was spiraled downwind. Differences between PW= downwind and PW= upwind increased with downwind distance and sample variability was higher when propeller was spiraled downwind.
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CitationThompson, Steven J.; Womac, Alvin R.; Mulrooney, Joseph; Deck, Sidney. 2005. Propeller wash effects on spray drift. In: The Society for engineering in agricultural, food, and biological systems, paper Number, AA05-007: 1-16
KeywordsAerial, application, drift control, agricultural aircraft, pesticide application, buffer zones
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