Al wrote:

There is indeed. In my experience, cycling the prop on a windmilling engine
has no effect. I'm talking about a constant speed prop on a single engine
aircraft, in this case a Mooney 201. Windmill RPM was about 800, and no
amount of pulling on the prop control would change that RPM. Obviously, if
the RPM doesn't change, the prop pitch didn't change, and the glide is not
affected.

Jim and I have 'round on this one before, but I stand by my observations.

Well, here's another data point on the same make and model, M20J. I don't have
the numbers to go with my observation, but subjectively when I pull the prop
control back at engine idle and ~best-glide, it feels like I just disengaged the
brakes.