3,693
edits
Difference between revisions of "Horsepower"
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→Drawbar horsepower (dbhp)
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This is equal to the displacement in cubic inches divided by 10π then divided again by the stroke in inches. [http://www.designchambers.com/wolfhound/wolfhoundRACHP.htm] | This is equal to the displacement in cubic inches divided by 10π then divided again by the stroke in inches. [http://www.designchambers.com/wolfhound/wolfhoundRACHP.htm] | ||
Since taxable horsepower was computed based on bore and number of cylinders, not based on actual displacement, it gave rise to engines with 'undersquare' dimensions, i.e. relatively narrow bore, but long stroke; this tended to impose an artificially low limit on rotational speed ([[Revolutions per minute|rpm]]), hampering the true power output and efficiency of the engine. | Since taxable horsepower was computed based on bore and number of cylinders, not based on actual displacement, it gave rise to engines with '[[undersquare]]' dimensions, i.e. relatively narrow bore, but long stroke; this tended to impose an artificially low limit on rotational speed ([[Revolutions per minute|rpm]]), hampering the true power output and efficiency of the engine. | ||
The situation persisted for several generations of four- and six-cylinder British engines: for example, Jaguar's 3.8-litre XK engine had six cylinders with a bore of 87 mm (3.43 inches) and a stroke of 106 mm (4.17 inches), where most American automakers had long since moved to oversquare (wide bore, short stroke) V-8s. | The situation persisted for several generations of four- and six-cylinder British engines: for example, Jaguar's 3.8-litre XK engine had six cylinders with a bore of 87 mm (3.43 inches) and a stroke of 106 mm (4.17 inches), where most American automakers had long since moved to oversquare (wide bore, short stroke) V-8s. | ||