Category Archives: agriculture

Of horses, trucks, and horsepower

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Horsepower is a unit of work production rate, about 3/4 of a kW, for those who like standard international units. It is also the pulling force of a work horse of the 1700s times its speed when pulling, perhaps 5 mph. A standard truck will develop 200 hp but only while accelerating at about 60 mph; to develop those same 200 horsepower at 1 mph it would have to pull with 200 times more force. That is impossible for a truck, both because of traction limitations and because of the nature of a gasoline engine when attached to typical gearing. At low speed, 1 mph, a truck will barely develop as much force as 4-5 horses, suggesting a work output about 1 hp. This is especially true for a truck pulling in the snow, as shown in the video below.

Here, a semi-truck (of milk) is being pulled out of the snow by a team of horses going perhaps 1 mph. The majority of work is done by the horse on the left — the others seem to be slipping. Assuming that the four horses manage to develop 1 hp each (4 hp total), the pull force is four times a truck at 1 mph, or as great as a 200 hp truck accelerating at 50 mph. That’s why the horse succeed where the truck does not.

You will find other videos on the internet showing that horses produce more force or hp than trucks or tractors. They always do so at low speeds. A horse will also beat a truck or car in acceleration to about the 1/4 mile mark. That’s because acceleration =force /mass: a = F/m.

I should mention that DC electric motors also, like horses, produce their highest force at very low speeds, but unlike horses, their efficiency is very low there. Electric engine efficiency is high only at speeds quite near the maximum and their horse-power output (force times speed) is at a maximum at about 1/2 the maximum speed.

Steam engines (I like steam engines) produce about the same force at all speeds, and more-or-less the same efficiency at all speeds. That efficiency is typically only about 20%, about that of a horse, but the feed cost and maintenance cost is far lower. A steam engine will eat coal, while a horse must eat oats.

March 4, 2016. Robert Buxbaum, an engineer, runs REB Research, and is running for water commissioner.

State bird suggestion: the turkey

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state bird stamps; robin cardinal

three US states use the (american) robin as their state bird, and 7 more use the (northern) cardinal. None use the turkey

As things now stand, three states of the union, including Michigan have the robin as their state bird. Another seven have the cardinal. Not that they have different species of robin or cardinal, they use the same species: the American robin, and the Northern cardinal respectively.

A thought I’ve had is that Michigan should change to have a unique bird symbol, and I propose the turkey, in particular the eastern wild turkey shown below. The robin is found in every state of the union except for Hawaii, and is found in several countries, it’s associated with Robin Hood, and with Batman’s side-kick. By contrast, the eastern wild turkey could be a unique state symbol. It’s basically found in no other country besides the US, and found in only a few US states including Michigan.

Eastern Wild Turkey. A majestic bird, and brave Maximum height: 4 foot.

Eastern Wild Turkey. A majestic bird, and brave. Maximum height: 4 foot.

The eastern wild turkey is a far more impressive bird than the cardinal or robin. Full grown, it stands 4 foot tall. Benjamin Franklin claimed to have preferred the turkey (likely the eastern wild turkey) to the eagle as the national bird of the US. In this wonderful letter to his daughter, Sarah, he says that it is a noble bird, useful and the source of sustenance. He also claims it is unafraid to attack a British regimen, claims that also appears in this song, “the egg” in the play/movie 1776. The turkey most definitely provided food for the Indians, for the early European settlers, and still provides for Michigan hunters to this day. Further, turkey feathers are the preferred choice for quill pens. They are used for scribes writing holy works, like copies of the Torah, and it is likely they were used for the declaration of Independence. The same history and associations can not be claimed for the robins or the cardinal. Those birds are basically attractive, and nothing else.

Not that attractive is bad, nor is it bd to have a state bird associated with Batman’s side-kick, or with a Saint Louis baseball team, but I don’t think either is particularly appropriate for Michigan. Not that there are no disadvantages to the name turkey: (1) it might suggest a slow individual or project, and (2) Wild Turkey is the name of a Tennessee bourbon whiskey. Neither of these are quite a bad as being a sidekick to the bat, or to the batman, and I think both are addressed by specifying that the state bird is the eastern wild turkey, and not just some random variety. What say ye, citizens of Michigan? Let’s do it before someone else takes the turkey.

Robert Buxbaum, December 16, 2015.