On Oct 1, 6:38*am, Ronald Raygun wrote:

I apologise for my earlier misunderstanding, which came from being
fixated on the boat example being driven by a water propeller using
power harvested from an air turbine. *I see that in the case of the
land based car you're discussing it is not using the air screw as a
source of power with which to drive the wheels, but the wheels as a
source of power with which to power the air propeller.

I don't doubt that this is possible, but I believe your analysis below
is wrong. *I offer a corrected version below.

Well, you're making progress. I suspect if you'll continue a rational
discussion with JB he'll be able to convince you that your "corrected"
analysis is in fact wrong.