Angling Of Air And Liquid, Rules Of Thumb; Water Sensitive Paper - Hardi COMMANDER TWIN FORCE Instruction Book

Angling of air and liquid, rules of thumb

To control wind drift the influence of wind speed and wind direction as well as the horizontal air current around the boom
due to forward speed must be minimised. Because it is a sum of two forces with variable direction and size that we have to
counteract for, the following can only be very rough guidelines.
Wind direction
• Head wind: Angle forward.
• Down wind: Angle back (if the forward speed is higher than the wind speed: angle forward).
• Side wind/no wind: Angle vertical or back. Only high forward speeds may require forward angling.
Crop condition
Bare ground/low vegetation: Low air speed and angling back will often be the best setting to avoid reflection of spray liquid.
Dense crop: The angling feature is ideal to help opening the canopy and improve penetration. If you follow the crop
movement as you are varying the angling you will find that at certain settings the crop will open more for penetration.
If wind speed, wind direction or for some reason forward speed changes during spraying the optimum angling is likely to
change too. Be aware that with certain combinations of air speed and angling you can "close" or flatten the crop and make
penetration impossible - follow the crop movement intensively especially when setting the air assistance and keep an eye
on the crop all through the application.
• It is most important that the sprayer operator is familiar with the above rules of thumb before using the TWIN sprayer.
• All volume rates, pressures and air adjustments stated in the following tables are, of course, guiding. Special conditions
regarding climate, crop quality, spraying time and applied chemical can change the procedure. The tables are showing
practice in northern Europe, and conditions may be very different in other countries. If you want some local advice you
are very welcome to contact the TWIN application expert at the HARDI importer or daughter company in your country.
• The volume rate can generally be reduced to half of what is applied with a conventional sprayer, but with a minimum
of 50-60 l/ha at 7-8 km/h (5.5-6.5 GPA at 4.5-5 mph. Exceptions are of course liquid fertiliser and herbicides whose
selectivity is based large droplets that will only stick to the weeds.
• Low drift nozzles can also be fitted on a TWIN sprayer and help reduce drift even further.
• If there is a detailed spraying instruction on the chemical label regarding drop size, spray pressure, spray volume rate
etc. this should be followed. Enclose 1 bag of water sensitive paper and instruction of how to use with all TWIN
sprayers.
ATTENTION! Often it will be necessary to drive with two different anglings, so the angling is changed when changing
driving direction after turning at the headland.

Water sensitive paper

USE WATER SENSITIVE PAPER TO HELP FIND THE BEST AIR SETTING.
Some time spent in different types of crops with clean water in the tank and some water sensitive paper will be valuable
experience for the future work with your TWIN sprayer. The paper can be cut into smaller pieces (to simulate the target) and
fixed with double sided tape at relevant places in the crop. Then spray with pure water and check the blue spots (droplets)
on the paper. This way you can test different spraying techniques. Water sensitive paper is available at your local HARDI
dealer, part No. 893211.
4 - Sprayer setup
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