Equipment

To achieve a wider application width, the flight altitude is usually 20–30 m. The application width (working width) ranges from 15 to 30 m depending on the dosage. Granulated fertilisers are also spread using centrifugal spreaders. The dosage is set on the dispenser on the ground before flight, and the pilot can only open and close the chemical outlet at the beginning and end of the field. Liquid chemicals must be atomised into droplets of the appropriate diameter. Ultra-low-volume (ULV) spraying with droplets of 50–150 microns in diameter is achieved using rotary atomisers driven by windmills or electric motors (on helicopters). These are usually highly concentrated agents – insecticides. This type of spraying creates a mist that settles slowly and penetrates the plants.

To reduce losses through evaporation and drift of chemicals, the working flight is conducted at an altitude of 1–3 m above the crop. This requires low wind speed (up to 5 m/s) and temperatures not exceeding 40 degrees Celsius. Medium and coarse spraying involves droplets of 100–500 microns in diameter, produced using several dozen spray nozzles distributed on pipes mounted on the trailing edge of the wing. These are usually aqueous fungicide solutions or herbicides for weed control. The main component of the liquid equipment is the pump assembly, suspended from the tank throat, equipped with a windmill-driven pump providing liquid pressure, a filter and a valve assembly for opening and closing the spray and mixing the suspension in the tank. The dosage is set by fitting nozzles of the appropriate diameter onto the pipes.