2015-08-21
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You can describe the size of a combine by the width of swath it can cut. Smaller sizes cut a 5-foot swath and larger sizes as much as a 20-foot swath; some special models, used in other areas, are even wider.
You can classify combines according to the way power is applied:
1. Tractor-drawn - with a combine driven by PTO.
2. Tractor-drawn - with a combine driven by its own engine.
3. Self-propelled - with a combine self-propelled and driven by its own engine.
And you can distinguish two major types:
1. Level-land or prairie type.
2. Hillside type, designed for work on steep slopes: this combine is used in the great wheat fields. Both tractor-drawn and self-propelled hillside models are available. Provision is made for adjusting the cutter bar to the steep slopes and for leveling the thresher and separator units. Recent progress in hydraulic devices has made hillside models more efficient and easier to operate; in fact, some hillside models are leveled automatically both longitudinally and laterally by a pendulum-actuated hydraulic system.
Weight of the different sizes of combines varies greatly - less than 3000 pounds for the smallest, about 9000 pounds for a typical 12-foot, self-propelled model, and more for the largest sizes.
The power needed for a typical 12-foot, self-propelled combine is about 60 engine horsepower; you can draw and operate a 5-foot combine with a two-plow tractor; and an engine of about 30 horsepower is used to operate the mechanism of the 6-foot size when it is not PTO-driven.
The rate of work (capacity) of a certain size depends on many factors – the kind and condition of the crop being combined, topography, moisture conditions, and other factors. But under favorable conditions, one man with a 14-foot, self-propelled machine can "combine" 20 to 30 acres of wheat in a day.
