Skip to main content
ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Aerial Application Technology Research » Research » Publications at this Location » Publication #339727

Title: Updating the USDA ARS rotary wing nozzle models

item Fritz, Bradley - Brad
item Hoffmann, Wesley

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2017
Publication Date: 10/5/2017
Citation: Fritz, B.K., Hoffmann, W.C. 2017. Updating the USDA ARS rotary wing nozzle models. Applied Engineering in Agriculture. 33(5):631-640.

Interpretive Summary: Setting up a spray application to obtain a specific droplet size is one of the primary duties of aerial applicators prior to any application. The droplet size generated is a function of the nozzle type, size and orientation, the spray pressure used, and the application airspeed. A set of computational models for 14 commonly used aerial application spray nozzles were developed and shown to provide accurate droplet size data as determined through comparisons with independently measured data sets. The models provide applicators a decision management tool for determining the droplet size associated with a given application treatment ensuring that their application conform to agro-chemical label and product efficacy requirements.

Technical Abstract: Optimizing aerial spray applications requires proper setup of the sprayer system, particularly with respect to nozzle selection and operation, which significantly affects spray deposition, product efficacy, and spray drift. Droplet size from an aerial application is a function of the combination of nozzle type, nozzle orifice size, spray pressure, orientation angle, and airspeed of the aircraft. A set of computational models for 14 commonly-used aerial application nozzles were developed and released for use by applicators. These models allow applicators to determine the droplet size characteristics associated with their specific nozzle and operational setup, determining the proper combination of orifice, pressure, orientation and airspeeds from 22 to 54 m/s (50 to 120 mph), which are commonly-associated with applications made from rotary wing aircraft (i.e. helicopters). Applicators can use the model from a computer with the spreadsheet version or from a smartphone app so ensure that their application conforms to the legal droplet size requirements specified on an agrochemical product label.