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A comment on Early electric fans. Parent comment

Re:Early electric fans by lqet on Thursday June 11, 2020 @12:45PM (#23490679)
Yup, I posted the original comment to quickly, the airflow indeed also pushes the brass disk forward, thus rotating the fan! An extremely clever solution that seems to be very easy and cheap to manufacture.
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Re:Early electric fans by perilunar on Thursday June 11, 2020 @09:29PM (#23495066)
> the airflow indeed also pushes the brass disk forward

The force on the disk is caused by an opposite force on the fan blades, cancelling them out (since they are connected by the frame and the bearings), so it cannot cause the fan to rotate.

The rotation is due simply to unbalanced thrust from the fan. The unimpeded side produces more thrust than the impeded side, so the fan turns to that side.

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