xerj wrote:
Thrust from a propeller drops as speed increases to a theoretical zero. When
this happens, what is providing the thrust to overcome drag? The forward
momentum of the aircraft?

If so, is it a case of the speed very slightly and imperceptibly dipping
below the zero thrust speed, getting a little thrust to bring it back to the
zero-thrust condition and doing this over and over again?

Thanks in advance.



The operative word above is theoretical. The prop can only get to this
speed if it is being pushed by another force. It can't pull itself to
this speed. The other option would be to place the prop in a wind
tunnel and blow air at it at a rate faster than what it can pull the
air. You could them reach a zero thrust point. However, you might
overrev and blow the engine shortly thereafter. :-)

Matt