Meter Settings

TM 5-3740-218-13&P (a) Calculate Swath Width (SW). Effective swath width can vary with altitude, speed, type of application, and wind speed. Determine swath width with a few test runs. LV system applications have an approximate SW of 150-350 ft at 100-ft altitude; ULV system applications are approximately 100-200 ft at 100-ft altitude. (b) Formulate Desired Flow Rate. Once the swath width is known, calculate the desired gallons per minute as follows: GPM = GPA x MPH x SW 495 where GPA is in gallons, MPH is miles per hour, and SW is in feet. Example: 1 gallon per acre, air speed of 55 mph, and a swath width of 200 feet: (1 x 55 x 200)/495 = 22.2 gallons per minute. This figure is now compared with actual gpm, which was computed in operational test. Adjust hydraulic pressure to bring actual gpm up or down to match desired gpm. For LV systems, this figure must be divided by number of nozzles (34). Different nozzles can then be selected to match desired gpm. GPM/NOZ = GPA x MPH x SW # NOZ x 495 Example: (1 x 55 x 200) = 0.65gpmpernozzle (34 x 495) (2) SD System Adjustment. To determine the desired meter setting, you must know the flight speed, the swath width, the flow rate of the material being used at each meter setting, and the desired application rate in pounds per acre. Once you know these variables, you can use the following formula to choose a meter setting: NOTE Excessive wind or an increase in flight altitude will have significant effect on swath width as well as accuracy of application positioning. Flow Rate (lb/min) = (App Rate (lb/acre) x SW x MPH 495 (a) Meter Settings. After determining required flow rate, select proper meter setting to provide flow rate. If pesticide being used is Agrisect, refer to table 2-6. For Agrisect, swath width will normally be 55 ft, assuming flight altitude of approximately 50 ft and minimal wind factor. If pesticide other than Agrisect is being used, a new flow rate table is necessary. Perform the following: 1 Install left and right hopper assemblies on PDU. Place large container under each hopper assembly. 2 Remove slinger assembly from PDU. 2-35