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Sep 8, 2026/ 0 Comments / in IMS News / by
Improving Forestry Topdressing with Ground-Effect Spreading Buckets

Forestry topdressing is a demanding aerial application requiring accurate product placement over large areas, often in steep and inaccessible terrain. Because this operation typically occurs only once every 10 years, achieving an even spread is absolutely vital.

Designed for High-Rate Forestry Topdressing

For the helicopter operator, the spreading bucket needs to do more than carry and discharge fertiliser. It needs to carry the maximum practical payload, evacuate the product reliably, maintain the required application rate and produce a consistent swath throughout the load.

The IMS Ground-Effect Spreading Bucket has been developed specifically around these requirements, backed by more than 23 years of experience designing and manufacturing specialist aerial spreading equipment.

Complete Product Evacuation

Toploading Fertiliser Aerial

Working in remote forests requires highly efficient loading systems to keep contracts profitable. Helicopters provide a logistical edge by operating from temporary loading sites right next to the forest block. However, true efficiency relies on eliminating unusable payload.

The hopper geometry is designed to minimise product hang-up to ensure the load continues to feed into the product spinner throughout the discharge cycle.

Product remaining in the hopper at the end of a run is effectively unusable payload. The Ground-Effect hopper and discharge system are designed to get the product out of the bucket and onto the ground.

Where required, an internal Product Agitator can be fitted to assist product flow with difficult or variable spreading materials.

High-Rate Spreading

High Speed Spreading Ground Effect

Forestry applications can require very high product flow rates. The spreading system must therefore move large volumes of fertiliser while maintaining the required swath width and distribution pattern.

Ground-Effect buckets use a powered spinner to accelerate and distribute the product away from the bucket. The spinner is driven by a dedicated engine selected for the required application.

Depending on the product and bucket configuration, Ground-Effect systems can operate at very high discharge rates, up to 400kg/ha (357lbs/ac) in one pass.

Application Rate Control

The Ground-Effect discharge system uses a pneumatically operated slide valve powered by an onboard compressor. The rapid valve operation provides a fast, positive shut-off at the start and end of each spreading run. The system can be configured using interchangeable orifice plates for different products and flow rates.

Additionally, operators can opt for the Granular Variable Flow Control system. Designed specifically for the application of dry media (from 1 kg to 200 kg/ha), this option allows the pilot to manually adjust the flow rate using a remote speed control while in flight, without the need to land.

Multiple sizes

Custom sizes for forestry topdressing applications

IMS offers 14 standard bucket capacities from 200 litres (7ft³) to 2,700 litres (95ft³), allowing the bucket to be matched to the helicopter and application.

The correct configuration considers:

  • ⦾ Available aircraft payload
  • ⦾ Bucket tare weight
  • ⦾ Product capacity
  • ⦾ Engine power
  • ⦾ Required application spread rate
  • ⦾ Required swath width

The objective is to provide a spreading system properly matched to the aircraft rather than simply maximising bucket size.

Product Protection

A PVC zipped hopper lid can be fitted to protect dry fertiliser and other spreading products from air flow and environmental moisture during flight.

GPS Application Mapping

Ground-Effect buckets can be integrated with modern GPS-based aerial application systems.

GPS guidance allows pilots to follow predetermined flight paths and record application tracks, providing forestry operators with digital records of the areas covered.

Load, Lift, Spread, Repeat!

That is the purpose of the IMS Ground-Effect Spreading Bucket.


Need more details about the Ground Effect Bucket?

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Contact Us

Are you a helicopter operator ready to optimize your fleet? If you want to ensure you have the precision equipment required for your next mission, get in touch with our team.

IMS Sales | imssales@imsheli.com | +64 21 583 033

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FAQ

Why utilize helicopters for steep terrain fertilizer application?
Helicopters offer unmatched agility in steep terrain, allowing pilots to fly accurate patterns directly over the tree canopy. Loading from small staging areas adjacent to the forest block drastically reduces turnaround times.
How does the Ground-Effect bucket handle high fertilizer flow rates?
IMS Ground-Effect buckets use an engine-driven spinner design that actively throws the fertiliser outward. This maintains a wide, even swath width even when dropping very large volumes of product. Because required flow rates vary depending on the specific forestry application, aircraft, and product being spread, the system is engineered to maintain a consistent distribution pattern across a wide range of high-capacity operational demands.
What stops fertiliser from bridging inside the bucket during a flight?
Ground-Effect buckets use a Complete Product Evacuation hopper geometry designed to empty completely. An optional internal agitator keeps dry media moving smoothly, and a PVC zipped Hopper Lid protects the product from environmental moisture and air flow.
Can the pilot change the application rate without landing?
Yes. When equipped with the Variable Control option, pilots can use a remote speed control to adjust the flow rate precisely while flying.