Lawn Mower Power - What is the HP?

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wrote:

Congress passed 6 years ago a law that will require the use of metric horses in measurements of horsepower. A metric horse is 0.84 the size of an American horse. This will increase the horsepower of all American engines by 16 percent.
There is a bill before Congress now to also change to metric power. Metric power is 90% of English power. If that law is passed, one horsepower will be 0.84 x 0.90 times what it was. This will also increase horsepower and will save gasoline.

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Whoops!
Americans don't speak English; they use 'Amurrican' with all kinds of letters left out; e.g. color instead of colour, humor instead of humour! Tire instead of tyre. And weird abbreviations such as 'sox' (instead of socks, which is itself a shortening of stockings). And how do Americans spell if it is a single sock? Also 'foto' from 'photo', itself a total shortening of the original (French) 'Photogravure' ; which is the way my grandfather, with his glass plate camera would have pronounced and spelt it! . The US gallon (rarely used elsewhere by the way) is approximately 80% the size of the Imperial gallon. Consequently it contains fewer litres! One of the few cases where anything 'In America', including Texas, is smaller than elsewhere?
Although somebody referred to George W. as "Shrub"!
Also some oddities of calculation?
While agreeing that adoption of the metric system has led to some very odd numbers, especially to someone brought up the other way; sheets of plywood still arrive 4 by 8 feet (48 by 96 inches), lumber as two by fours, although they never are, the numbers referring to the rough lumber dimension before planing and now called something along lines of 100 millimetres by 50 mm. or something? Carpet rolls still seem be in 12 foot widths?
Oh and while we are on the subject; it is more correct to spell it as "metres" not "meters".
'Meters' are things that measure other things; as in 'Voltmeter', 'Ammeter', "Electricity meter', 'Test-meter' or 'Watt-meter'; OK?
But have sympathy for those of us please, who were brought up learning and using 'Pounds, shillings and pence' along with 'Rods, poles, chains and perches, for land, measurements! (Encountered one world location where land is still measured, advertised and sold in Perches btw!)
Then there are/were metric tonnes, nautical miles, knots per hour, guineas, half crowns, florins, ha'pennies (half pennies), and now Euros (a sort of European dollar if you get the drift?). And one could go on to bushels, bales of cotton, pounds of coffee and housing and building products measured in square metres. There are roughly ten square feet in a metre squared, as it is expressed.
Oh and by the way in Canada we measure vehicle fuel consumption in litres per 100 kilometres. Although some hold outs still, think in miles per gallon; same miles but Canadian Imperial gallons. So we get more miles per gallon (Oops, sorry; that's fewer litres per 100 kilometres!) in Canada. Got that, eh?
You say tomato? We say tomato? (Gee I alwys thought there was an 'e' in that word somewhere; guess I was wrong)?
Any way cousins; have fun with our 'common' language, we do. Although some of us even use French first; and because a significant proportion of our population has that background and culture, it enriches us. Maybe Spanish will do so also?
Although these days maybe smarter to learn Mandarin Chinese or Indian Hindi?
With our warm regards.
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mm wrote:

In the 18th Century, James Watt invented the HP. He defined it in terms of feet, pounds, and minutes. Before the Metric System, nobody knew exactly what feet, pounds, and minutes were; but the HP was a good marketing device.
Late in the 19th Century, the Germans defined the PS, which was a horsepower slightly adjusted to be easier to calculate with meters and kilograms. One PS was .986 HP.
That's what was meant by the Metric Horsepower. Countries all over the continent adopted it under different names. Nobody cared if a 5 PS engine was only 4.93 HP. They loved the easier calculations. It was never part of the Metric System and Europe outlawed it in 1992.
The difference in how HP is measured can matter a lot more than the difference between HP and PS. I bought a 1970 BMW motorcycle rated at 57 SAE HP and 50 brake HP. The former was measured at the crankshaft. The latter was measured at the rear wheel.
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wrote:

Hey, I just made it up. I had no idea there was such a thing as metric horsepower. Unless you tell a better yarn than I do.

Is that running at the same speed in both cases?
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mm wrote:

You inspired me to look it up. Thanks. I think the Japanese still use metric horsepower. The modern unit is kilowatts.

I believe so, given in RPMs. Brake HP was reduced by what was lost in the transmission and ring-and-pinion. Maybe it was also reduced by the friction of distorting the back tire. It's possible that the SAE standard allowed more liberty with the exhaust system and the alternator.
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