Sprayers put to the test

Kondinin Group researcher Chris Warrick weighs the rear axle of one of the nine self-propelled sprayers.

By any measure the purchase of a self-propelled sprayer is a significant investment and with some units costing as much as a new harvester, it is not a buying decision that should made lightly.

Kondinin Group put nine self-propelled sprayers through their paces, testing boom stability, pressure distribution, axle loadings, operation and features.

The Group's research and development manager and engineer Ben White said machines were run over a portable test track to assess different aspects of the boom's stability.

"Boom stability directly influences spraying accuracy. While nozzle choice and spray pressure also affect drift, a boom that can be run safely and consistently at half a metre above the ground is an excellent starting point," Mr White said.

"With specially-designed ultrasonic height-logging equipment, testing results are a clear indication of boom performance.

"Height was logged electronically 50 times per second using custom-made ultrasonic height sensors."

Boom stability results varied between each machine, according to the fitted boom width and obstacles on the test track. The toughest of all obstacles, the simulated tree test, put booms through a series of tough 20m radius turns.

On this particular test, some machines encountered boom strike, hitting the ground and causing the breakaway section of the boom to fold back. Others, including Australian built models, navigated the test with relatively stable boom dynamics.

Sprayers are heavy machines when fully loaded, weighing up to 20 tonnes and have comparatively narrow tyres.

"In an ideal world this weight would be spread evenly across both the front and rear axles to reduce individual axle loadings as much as possible," Mr White said.

"But all machines were rear-heavy to a degree, with some shifting more weight than others when carrying a load.."

Mr White said that overall, results showed a significant level of design and consideration has gone into all machines since self-propelled sprayers first appeared on the farming scene.

"The Australian-made sprayers, with limited research and development budgets, performed well with those of the larger overseas machinery manufacturers," Mr White said.

The research report gives the lowdown on nine different machines including the Case IH Patriot 4420; Goldacres Crop Cruiser; Hardi Saritor; John Deere 4830 and 4930; Miller Condor A75 and Nitro 4275; and the RoGator 1084 and 1286C models.

Machines were tested for spray pressure uniformity, axle weight splits when loaded, driving characteristics, cab comfort and visibility, plumbing and general operation.

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