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Old 02-10-2012, 06:30 PM   #146
SUB-FT86
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Quote:
Originally Posted by Exage View Post
This was already answered with the bike question I believe.

Power = Force X Distance / Time

HP is roughly calculated with: Torque x Rpm / 5252

5252 is some conversion factor I don't have the heart to research right now.

Speed of the engine torque is applied at gives you the amount of power the engine is producing at RPM.

Something like 10m (~33ft) cable with a 10kg (~22lbs) weight attached, and you have a spool/drum to do a vertical lift. I'm in metric sorry for those who use the imperial.

The force is 10kg x 9.81m/s2 (gravity), distance 10m. Two electric motors lift the weight up vertically. One motor takes 20 seconds the other 30 seconds. They didn't do the same work despite delivering the same force:

(98.1N X 10m / 20s) = 49.1W : In 1 minute this motor can lift 10kg 3 times.
(98.1N X 10m / 30s) = 32.7W: In 1 minute this motor can lift 10kg twice.

Also the RPM of the spool will be different: I'm sure you can figure out which is faster. It's hard to explain, I hoped going liner (strait line) helped.

____________

People try to keep RPM low. Fuel economy, engine wear, noise etc... The way to counter lack of power at daily driving speeds is an increase in torque. This is achieved through drive-train design. Hence when SUB says his RSX is gutless because it has little torque, what he means is it develops insufficient power for his liking at low rpm (or the whole range).
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