June 17, 2008 16:20:49
Posted By Peter Bentley
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An eagle-eyed ex-engineer has spotted a dodgy explanation in The Undercover
Scientist. I trust this reader, for it's my Dad:
On pages 57 and 58 of the Undercover Scientist you refer to pistons connected to a camshaft. I think you meant crankshaft. The cams are the lozenge shaped bumps on the camshaft which operate the engine valves. Yes, we somehow all managed to miss this one. The book should read: "Each push on the rim is a linear motion, and that is converted into a rotary motion by the hoop. Connect a piston to a crankpin (often connected to a crankshaft) and the piston rotates the crankpin, pushing it round and round." and later "Nevertheless, the principles of the engine remain exactly the same: fuel and air is injected into the cylinders and is ignited by sparks (produced by the spark plugs), the resulting pressure from the explosion moves the pistons, which pushes the crankshaft around, and through a series of gears, makes the wheels turn." Future editions (and foreign versions) will have this amendment... Thanks Dad. |