In 1790 John Curr of Sheffield, England, made an atmospheric steam engine with a 61.0-inch diameter piston and an 9.50 ft stroke. The engine operated with a mean effective piston pressure of 7.00 lbf/in2 and ran at 12.0 strokes per minute. It produced a duty of 9.38 million.
Determine (a) the thermal efficiency,
(b) the horsepower output, and
(c) the boiler heat input rate of this engine.
Ignore the boiler feed pump power requirement.