Thread: Discussion Efficiency of a ducted fan
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Old Feb 01, 2008, 09:03 AM
hokonghing is offline
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TB, let me give it a shot, first, efficiency has no units, like JRB said same unit above and below and if you divide the same unit, result is non-dimensional, no unit, so it is represented by %.
ok, you try to compare two different fans with same motor and try to find out which one has better efficiency, say first motor with a input (watt), give you "A" ozs of thrust and on the second fan with same motor and SAME input watt give our "B" ozs of thrust, and if "A" is higher than "B", usually we say fan "A" has higher efficiency than fan "B", does this make sense?
You note I use the word usually, because there are lot other factor come in, like amp draw, rpm voltage drop, so higher effeciceny sometimes is not necessary the best setup. confusing, right?
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