Tandem Deere Tracked Tractors Provide Awesome Power
Bill and Judy Zell, together with their sons Gavin and Wayne, farm 47,000 acres of wheat, barley, and chickpeas near Collarenebri, New South Wales, Australia.
Like all farmers, the Zells work hard to get their crops sown as quickly as possible once conditions are right. They run the biggest equipment they can 24 hrs. a day to get their crops into the ground.
However, the Zells farm in a remote area where they face a shortage of skilled operators. Adding more tractors and seeders into their operation would require more drivers. To solve the problem, Gavin developed a system to join a pair of Deere 9400T tractors so they work as a single unit. They tested the tandem tractor hookup during seeding in July, 2010. Satisfied with the results, the Zells then built a 212-ft. wide air seeder to match the capacity of the tandem tractors.
Joining the tractors involved developing a heavy-duty hitch that mounts on the drawbar of the front tractor. It’s designed to move up and down to accommodate movement between the coupled tractors. The hitch incorporates a pair of hydraulic cylinders and accumulators that provide dampening of movement. The hitch can be locked hydraulically when the front tractor is used for other tasks as a single unit.
A steel frame mounts permanently under the rear tractor, running back to the drawbar hitch and bolted to the underside of the tractor frame with plate steel brackets. A large ball joint on front of the rear tractor connects the two tractors, with the frame providing a direct link between the hitches of both tractors.
A series of hydraulic lines run back along the side of the rear tractor. These lines plug into the hydraulic outlets of the front tractor, allowing the hydraulic systems on both tractors to be used to power the giant air-seeder. Each tractor powers one of the two seed carts attached to the seeder.
A second set of CommandARM controls are installed in the cab of the front tractor and these controls are linked by electric cables to the corresponding controls on the rear tractor. A push-pull cable connects to the transmission of the rear tractor to provide gear changes.
The driver sits in the front tractor and is able to perform all operations of both tractors – except switching the rear tractor’s lights on or off. Only the front tractor is steered – the rear tractor follows its lead. A GPS and auto-steering system on the front tractor is linked to the air-seeder steering system and this ensures that the air-seeder accurately follows the tractor, including turning between passes, and increases the maneuverability of the rig.
The Deere tractors are run at 1,900 rpm’s and burn 13 gal. of diesel each hour – a total of 26 gal. per hour for the combined unit. The tandem tractors and air-seeder work at 5.6 mph per hour, with the rig covering 2.5 acres each minute. Over a typical 18-hr. day of seeding the big rig is able to seed about 2,500 acres.
The tandem tractors and air seeder worked flawlessly during the 2011 planting season, seeding about half of the Zell’s crops. The rest of their crops were planted with two 80-ft. air seeders and a 60-ft. unit, all working around the clock.