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There is question at Space.SE If I drop a feather from orbit, would it burn up or “hit” the ground? there is an attempt to answer the question, but the mass of pigeon tail feather and possibly the drag coefficient is required to complete the answer.

I have looked around on the web and if there is an answer it is not jumping out at me.

What is the mass & drag coefficient of a pigeon tail feather?

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    $\begingroup$ An African or European pigeon? $\endgroup$ – terdon Jun 15 '15 at 18:28
  • $\begingroup$ @terdon - oddly enough, the same question was asked in a comment in the question that gave rise to this one. $\endgroup$ – Pete Becker Jun 15 '15 at 19:20
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I just weighed a pigeon tail feather (~10 cm) long. The mass was 0.05 g. Although all tail feathers are not equal in length (and all pigeons are not equal in size), this is probably a good approximation.

Measuring the drag coefficient is going to be very challenging, because it will vary with the orientation of the oncoming airflow. A feather falling with its broad surface (in this feather ~1.2 cm in chord width) perpendicular to the flow will have a much high drag coefficient than a feather falling with the broad surface parallel to flow.

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  • $\begingroup$ Heh, nothing like the old fashioned empirical approach. I would expect the feather to orient itself with the pointy bit downwards though, it should be relatively standard. $\endgroup$ – terdon Jun 15 '15 at 18:30
  • $\begingroup$ @terdon such alignment, however, will only happen after the feather hits the atmosphere and survives the initial onslaught of unsuspecting air molecules. The orientation is uniformly arbitrary before the feather touches the atmosphere. $\endgroup$ – John Dvorak Jun 15 '15 at 19:25
  • $\begingroup$ @JanDvorak yes, but we only care about the orientation after it hits the atmosphere. Obviously, there will be no drag coefficient in vacuum. I am guessing that as soon as it hits the atmosphere, the drag will orient it thusly. $\endgroup$ – terdon Jun 15 '15 at 19:34
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    $\begingroup$ Dropping most feathers (certainly primaries and body coverts, anything else should be in between) actually leads to them falling in a fluttering motion, rather than pointy-end first. Pointy-end first is unstable (c.f. rocketry etc., or ask at physics.se) Try it and see, it's also great for entertaining a cat. A sheet of paper will often do the same. $\endgroup$ – Chris H Jun 15 '15 at 20:06
  • $\begingroup$ @ChrisH I think (no idea really) that pigeon feathers, being relatively large (I'm thinking of entire plumes here, not tiny fluffy ones) would orient themselves pointy end down because of the extra weight of the plume. I may well be wrong though. $\endgroup$ – terdon Jun 16 '15 at 11:50

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