I flew a motorglider with an MT-7-A electric CS prop which takes 90 seconds to fully feather. Contrast that to a hydraulic governed prop, which takes just a few seconds to go from one extreme to the other. Quite the shocking difference!

Compared to other electric constant speed props, is 90 seconds to feather slow, fast, or par for the course? What models would be considered fast and what models would be considered slow?

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    $\begingroup$ 90 seconds - wow! That must seem interminable. I'll be interested to see what the range of values is. Of course, my reference point is the Hamilton Standard 4-blade props on C-130's... you put the Condition Lever in "feather" and the prop stopped right now! $\endgroup$
    – Ralph J
    Feb 27 at 4:04
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    $\begingroup$ @RalphJ it does feel interminable! I actually measured it with a timer, because I just couldn't bring myself to believe the POH: sure enough, it's right on 90 seconds. $\endgroup$ Feb 27 at 19:34
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    $\begingroup$ 90 seconds!? That might as well be classified as a fixed-pitch prop! 😂 $\endgroup$ Mar 3 at 15:37
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    $\begingroup$ @JuanJimenez it kind of is! I notice it really gums up the pattern on busy days: aviation.stackexchange.com/questions/99153/… $\endgroup$ May 19 at 13:25
  • $\begingroup$ The slowness of feathering may be a safety feature (for pilot error). With electric motors, a bit more research might be put into a more robust system, perhaps replacing spoilers with a reverse pitch function. I'm seeing an electric pitch control system much like flaps, except one (or more) angles is negative! $\endgroup$ May 20 at 13:47


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