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Checking the Crops

Frequently Asked Questions

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How much does the drone carry?

Our DJI T20 can carry up to 20L or 20kg. However, a more relevant question is, 'what area can the drone cover at what water rate?' We use a rapid refill system from a tank on a Polaris™ ATV.  From landing with a depleted spray tank, we can be back in the air, all loaded up again, in just over a minute.  We plan our spraying so that the drone’s spray tank needs refilling when it is near us in its flight course. We fill it from a 200L agitating tank mounted on a Polaris™, which itself is refilled from a 1000L tank mounted on our support vehicle.  So whilst the spraying drone itself carries 20L, the drone spraying system we deploy can carry 1200L

What tasks are the drones best suited to?

Our on-farm and on-task experience has shown that in comparison to other equipment, a drone is a great option for:

  • Precision herbicide/fertiliser application to a broad range of cultivations.  No driving on the crop is required (thus, no tram-tracks required) and the downdraft from the drone pushes the product through the crop canopy and mixes it through the plants.  We have demonstrated this effect on a variety of different types of summer and winter crops.

  • Damp surfaces: the irony of agricultural spraying is that the chemical effect is greatest when the target plants are growing the most vigorously – normally after rain or irrigation. However, ground-based equipment causes crop and surface damage and compaction layers when driven on damp surfaces.  The drone can gain all the benefits without causing the same damage to the ground, maximising the desired effect on target plants while preserving the crop.

  • Smaller cultivations:  We have personally experienced the difficulty pf trying to get large spray equipment in when you want single-digit hectare properties treated.  Rigs and air tractors are great for big areas, but lose efficiency on smaller jobs.  Our drones are perfect for treating smaller cultivations. 

  • Waterways: one of an agricultural drone's most unique abilities. Waterways are effectively treated by drone, which is easily able to deploy the desired chemical or product on the surface of affected waterways.  Water Hyacinth, Sesbania Pea and other targets have been successfully cleared by our drones.

  • Trees:  The drone can hover above a target tree and effectively mist or deluge it. The downdraft helps penetrate the target, which is very effective for insect pest targets, such as processionary caterpillars. 

  • Difficult-to-access terrain:  The drone can safely spray where using other spray equipment is risky or unworkable.  We have proven time and again our ability to clear infestations of plants like Lantana and Prickly Pear.

  • Night spraying operations: The drone can perform night spraying operations without the substantial risk of spraying at night with a manned aircraft.

How long do the drone batteries last?

Each drone battery lasts about 15 – 20 minutes.  Our trailer setup carries a large generator that is continuously recharging drone batteries during drone operations.  We ensure we always have a charged battery ready to go when the drone needs a battery change.  Additionally, the drone constantly reports battery state to the operator, including a number of warning phases as the battery gets low.

Do you fly it manually or does it fly itself?

Our DJI T20 drones may be considered semi-autonomous.  The operator defines the work area on an electronic map, determines the height to spray from, speed to spray at, type of nozzle being used (with resultant swath width) and required water rate per Ha.  Obstacles are marked off as avoid areas. The radar system is set to passively or aggressively maintain height and the drone is set either to use D-RTK or just its two on-board GPS units.
The drone then makes its computations and requests permission to launch and conduct the task.  By law, the operator must be immediately ready to take manual control of the drone from the flight computer should it be required.

Spot-spraying and similar tasks are primarily conducted by the operator.

How accurate is it?

In GPS only mode, our drones spray and spread with extreme accuracy in comparison to out of GPS-only mode. By this, we mean its spray runs will be parallel and accurately spaced.  However, to make the drone accurate in comparison to a fixed point on the ground, it needs to use D-RTK.  This brings accuracy from approximately a metre to about a centimetre or so.  This high level of accuracy reduces the buffer zones required from things like fences and other obstacles.

What height does the drone spray from?

We like to conduct spraying operations from 1.5m above the target.  While this sounds high in comparison to a spray boom at 0.75 to 0.5m, the drone utilises the downdraft produced by its rotor system to accelerate the spray toward the ground.  From 1.5m with 95⁰ even flat fans, we achieve seamless coverage underneath the drone and a tidy 4m swath width overall.

What if it runs out of spray?

We plan not to run out of spray, but refill the drone at a planned ‘pit stop’, where it may also get a battery change.  If drone systems do run out of spray, the drone automatically ceases operations, creates a ‘waypoint’ of where it was when it ran out of spray, returns to us for a refill, then heads back to where it left off, and recommences spraying.

What chemicals can it use?

As a professional and approved aerial application system, the DJI T20 drones can deploy all APVMA approved chemicals that include approval for aerial distribution.  This includes compliance with all label instructions and restrictions. 

How much area can it cover?

Our operations demonstrate that at 20L/Ha water rates, about 3 Ha can be covered an hour.  At 40L/Ha water rate, it is around 2 Ha an hour.  As the water rate increases, the area covered per hour decreases.  This is reflected in our pricing.  
A limiting factor may well be the Delta T of the day and/or other spraying environment conditions.  As a result, for planning, we suggest we can cover 10 Ha a day assuming a chemical that needs appropriate environmental conditions being applied at a water rate of 40L/Ha.

What if there are trees, power poles, fences or other obstacles in the field?

While our drones are programmed with technology to avoid obstacles such as trees, power poles and fences, our remote pilots always cross-program to ensure all obstacles are programmed to be avoided.  Our pilots mark off known obstacles during field planning, while the drone uses its radars to avoid unexpected obstacles.

Can the drone spray in the rain?

Our DJI T20 drones are dust-proof and water-proof (IP43 protection rating, IEC standard 60529).  This means they can fly in light rain without risk, which is useful for fertilising operations.  Of course, for pesticide applications, we must apply label restrictions on application in or before expected rain.

Can the drone spray at night?

Drone Commander has approval to conduct night flight and spraying operations where the product being sprayed and environmental conditions are suitable.
A daytime field survey is preferred where night operations are to be conducted, and D-RTK are used for these field surveys.

How is the risk of spray drift managed?

Drone Commander Australia have a best practice spraying system to continue producing consistent and predictable spray quality.  Outside of specific target situations requiring finer spray quality (such as orchards), we use only TeeJet™ Air Induction nozzles producing Very Course, Extremely Course and Ultra Course droplets.
We also deploy an integrated Kestrel™ Ag Meter that registers environmental conditions every two seconds, linked to an operator alarm system that activates if any limit is approached.  The Kestrel™  emails these warnings to Drone Commander, along with a detailed report of spraying conditions (readings every 2 sec) at the end of the task.

What nozzles do the drones use?

We use a range of TeeJet™ nozzles, using stream-jets for getting fertiliser into the soil. We prefer Air Induction nozzles for drift resistance, particularly the even flat fans.  We can also use misting type nozzles for specific tasks and products used in horticulture and orchard-type settings.

Is there a chemical exposure risk to people?

Ag chemicals are safe if used according to the label and safety data sheet directions.  Our operators are all required to have their ChemCert certifications and are equipped and approved to handle ag chemicals, including using them from the drone. As a relatively small piece of equipment, flushing and cleaning is also simplified.

Can you use the drone near airports?

Our pilots are licensed and equipped to comply with all air traffic requirements.  We carry ground to air radios, monitor the local air traffic frequency, and when required, make broadcasts to inform other air users of our operations.  If the operation is near an aerodrome with an active air traffic control tower, our operators will liaise with the airspace authority to coordinate operations.

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