HORSE POWER IN REVIEW

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Beach Hill Road, New Ashford, Massachusetts 01237

Horses have been with us for about 4,000 years. In the draft horse class, 2- and 4-horse teams were quite common, 6- and 8-horse teams were used on the large freight wagons. We still have the 8-horse Budweiser team. Twenty to 30-horse teams were used to haul the early western combines; a few 40-horse teams, other than 40-horse circus show teams were actually worked. All this is is the pulling power of horses directly applied to moving various size loads.

About 300 years ago horses were used to develop rotary power, first the sweep power, (1 to 16 horses hitched to levers attached to a vertical axle.) Then about 1800 circular and treadmill type horse powers appeared so we had pulley or belt power of from 1 to 16 horsepower. Everyone lived with live horsepower and had a good idea of the power of the horse, then the mechanical horse appeared. Early steam engines replaced horse powers. Steam and gas tractors started to replace horse teams and confusion started.

James Watt developed the horsepower formula so that he could rate the power of his steam engine as compared to the power of a pulling horse or combination of horses. He actually experimented with a draft horse and found, over an average day, a moderately pulling horse could raise 100 lbs. of coal ore out of a mine shaft 220 feet deep and the horse walked the 220 feet needed to raise the load to the surface in one minute. This amounts to 100 x 200 or 22,000 foot pounds of work in one minute. To compensate for friction loss in his engines, Watt added 50% thus 150 x 220 equals 33,000 lbs. of work in one minute and this became the standard 1 HP. This can be broken down in a number of ways lifting 3,300 lbs. 10 feet in one minute; lifting 1,000 lbs. 33 feet in one minute; lifting 550 lbs. 1 foot in one second; lifting 1,980 lbs. or 99 tons 1 foot in one hour. Simplified one horsepower amounts to hauling 150 lbs. of coal out of a hole 220 feet deep in one minute.

In the beginning mechanical horsepower and live horsepower appeared to be distant relatives and to this day many people still think they are not closely related. Watt and other steam engine manufacturers, and later the early steam traction engine and gas tractor manufacturers, knew mechanical horse power and did a good job of promoting this type of horse power. At the same time generations of horse owners and users knew all about live horsepower. Now note the differences using the treadmill type horsepower and the early Fordson as simple examples. A cordwood saw belted to a 1 horsepower would saw wood; a 2 horsepower belted to a small threshing machine would thresh grain so when early small farm type steam engines came on the market the farmer purchased a 1 HP engine to saw wood or a 2 HP engine to pull a threshing machine and they could not handle the job. They found they needed a 3 HP or a 6 HP steam engine to do the previously mentioned same work. The same applied to early gas engines except they needed a 4 HP and an 8 HP gas engine to do the same work as the 1 or 2 horsepowers. Note the differences between live horsepower and mechanical horsepower also between steam horsepower and gas horsepower.