What would happen on a 6 blade propeller if each blade opposite another was pitched in completely the opposite direction.


closed as unclear what you're asking by jwzumwalt, David Richerby, Ralph J, fooot, ymb1 Aug 29 '18 at 15:11

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    $\begingroup$ This seems entirely hypothetical, and we're focused on more practical matters. $\endgroup$ – David Richerby Aug 29 '18 at 11:58
  • $\begingroup$ Aren't they mechanically linked via some gearing in the propeller hub, thus that could never happen? $\endgroup$ – CrossRoads Aug 29 '18 at 12:43
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    $\begingroup$ This document shows how a McCauley 2-blade propeller has its pitch controlled, 6-blade would likely be similar, but just more of it. airtreknorth.com/uploads/4/7/2/4/4724302/… $\endgroup$ – CrossRoads Aug 29 '18 at 13:08
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    $\begingroup$ What do you mean by "completely opposite direction"? perpendicular? each blade 60° more pitched? $\endgroup$ – Manu H Aug 29 '18 at 14:23

For a start, whoever built the propeller would get investigated for possible drug/alcohol impairment on the job.

In terms of trying to run the propeller, it would generate a lot of noise (from turbulence of the blades running in "reverse pitch", possibly stalled relative to the airflow induced by the previous blade) and very little or no thrust. If it's on a piston engine (or electric motor, assuming a model aircraft or drone case), the engine/motor is likely to overheat after a short time due to lack of cooling airflow.

Finally, it's possible vibration induced by the noise-causing turbulence could lead to a structural failure of either the propeller itself, the engine/motor, or the engine/motor mounts.


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