James Watt

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Kansas Bad Man

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In the last 500 years man has really got into measuring this and that, one day James w. working on the measurement of force, he first he concluded that to measure it, it had to be a push pull thing, and something had to move so first it was "work" measured in distance and pounds. In his day, most work in his part of the woods was being accomplished by the horse. James observed that one horse could move 550 lbs one foot in one second, for an 8 hour shift. So James was the inventor of the term used today "H.P."

Now to apply James W. s formula to a rotating force "running engine crankshaft" to H.P. a machine had to be devised that could measure foot lbs of rotating force which we will refer to as "torque"

My dyno is of the water brake design, it consists of a torque convertor, a driven impeller driving an impeller in a controlled way by regulating the friction component between the two impellers which is water. The driven impeller is connected to a exactly one foot long torque or moment arm. This moment arm is connected to a highly accurate and one that is capable to calibrate for accuracies gage that reads in lbs. The formula for converting foot lbs of torque to H.P. is "torque x rpm divided by 5252" . The dyno has on the control panel a throttle that controls RPM and a valve that controls torque readings in foot pounds. Its easy to control and easy to read with precision H.P. after converting, can be calculated with in one H.P., when testing a 500 hp pull , it can be done time after time, the dyno can give you accurate numbers, the idea that it cant is just simply not true.

Of course if an Elephant was Watt's OBSERVATION instead of the horse-------o_O
 

Jim Richardson

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I seem to think that I have read that, James Watt under rated the work done by a horse, to over emphasise the power of his new machines.

A bit like advertising bhp at the crank as against bhp at the rear wheel.
 

timetraveller

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My memory is that a horse cannot produce a Brake Horse Power for very long and I also seem to remember that the value was obtained from horses towing barges along the canals. Over to Google for those who wish to check.
 

Howard

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Strange how we sort of remember things these days. I was told that Watt did all the experiments and calcs to work out a horse power, then decided the horses he used were a bit old and tired, so he added "a bit" to his original figure.
It may be splitting hairs, but a steam engine fan told me a 4 hp traction engine doesn't produce 4 (b)hp at the crank, wheels or anywhere, but it can do the same amount of work as 4 horses in a day - 19th century farmers knew what a horse could do, but had no conception of bhp, ft.lbs etc.
H
 

Kansas Bad Man

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The point of this thread was that small horse power readings were said not to be obtainable on a dyno on another thread. I disagree hence the thread.

Cheers ------ Max
 
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