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The Bi-Rotor Rides Again

Indiana-based Davaus had the fabled machine in the field with plans to continue innovation.

Less than a year after Indiana-based Davaus bought the XBR-2 model Bi-Rotor combine from inventor Mark Underwood’s estate auction in north-central Kansas, the new owners had the machine harvesting corn and soybeans in Indiana with big plans for its future.

“I’m proud to say it performed flawlessly,” says Dave Hockemeyer, president and co-owner of Davaus, LLC of Hoagland, Indiana.

On a Facebook video update of the machine’s progress (click here to see the 10-minute video), Hockemeyer and director Austin Ehle fired up the Bi-Rotor, which they said has a new Caterpillar engine and revamped electrical and hydraulic systems.

“We’re proud to get it back to life,” Hockemeyer says. 

Dave Hockemeyer, president of Davaus
Dave Hockemeyer

The XBR-2 has a completely different architecture than modern combines, Ehle says. The concave co-rotates with the rotor, but at a different speed, which allows for a significant increase in threshing and separation capacity. The Bi-Rotor has but three belts on the entire machine. There are fewer motors and chains and many fewer parts than today’s combines. The machine has full tracks across the bottom, giving it a dramatic increase in flotation and turning radius. It is equipped with a 400-bushel grain tank, and a 3.5-bushel-per-second unloading capacity via a conveyor system. 

Simply, the Bi-Rotor was ahead of its time. “It’s a 1994 machine with the capabilities and capacities of a lot of the machines we find on the market today,” Ehle says. The pair hint in the video that they plan to use the Bi-Rotor concept combine as base architecture for a new type of combine. 

The Bi-Rotor Dream

Underwood was in his teens when he first envisioned a combine threshing system that used dual rotating concaves, which was far more efficient, and gentler on crops than conventional threshing systems. He and Ralph Lagergren, his cousin, formed a company called Agri-Technology L.P. to test prototypes of the bi-rotor system. 

The XBR-2, a machine designed from the ground up to contain the unique Bi-Rotor system, was built by a small yet devoted team of engineers, welders, and craftsmen in the early 1990s. The prototype combine used a Caterpillar engine and had a Caterpillar track undercarriage. An anticipated marriage between Agri-Technology and Caterpillar to build the combine did not materialize, and the cousins sold 17 patents to Deere and Company in 1995 for an undisclosed sum. Underwood, who worked for Deere for a period, eventually moved back to his farm near Burr Oak, Kansas, where he farmed and invented until he died in 2017. 

Davaus bought the combine at the Underwood Estate auction October 29, 2018, for $22,000. At the time, he told Successful Farming that his team envisions a combine that helps farmers become more efficient. “We understand that medium to small farmers have to meet their bottom lines, and we’re going to try and help them out. We’re planning to continue what has been started here,” he said after the combine sold. 

Davaus Objectives

Prior to Mark Underwood’s estate auction last year, Lagergren said “…we won’t ever see the Bi-Rotor as we envisioned.”

Yet Davaus has a vision of its own: a combine that’s friendly to own, operate, and repair “…for the forgotten farmer,” Hockemeyer and Ehle say in the video. “We’re looking for a machine that’s built on efficiency. We want to get the most out of the asset that we can. We want a machine that has excellent return for the growers.”

“Take in the simplicity,” Ehle says during a walk-around of the combine. “That’s the core of the new harvesting architecture that we’re developing in the next generation of the combine.” 

It is a simple foundation, but doesn’t mean there will be fewer features on the new machine compared with current combines, he adds. 

“Our angle is that we’re evaluating and reinventing the architecture the harvesting machine is built on,” Hockemeyer says. “As we come at it with a fresh slate and new ideas, we’re going to be emphasizing efficiency.” 

Hockemeyer says interest in the Bi-Rotor combine remains high. 

“That was a pretty fun day. An emotional day,” he says of the date the company bought the XBR-2, and they met with the original design team. “We met them all, and they have been behind us 100%. We want to thank them all in their support to date.”

Within a day of the sale, Davaus received phone calls from supporters who wanted to be a part of the Bi-Rotor’s next chapter. “And we felt you deserved an update on where this machine stands,” Hockemeyer says. 

He encourages interested folks to follow the Davaus, LLC Facebook page and check in at the National Farm Machinery Show for further updates.

What Davaus Does

Davaus is a small engineering and fabrication company with close ties to the founders’ family farms in northeast Indiana. Its products and innovations are based on a combination of science, technology, nature, and practicality. The company makes the SeedRight plates for growers to plant small grains and cover crops with row-crop planters. It also makes the Ferret, a wireless monitor that helps farmers identify problem areas in tile drainage systems. 

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