Originally Posted by
Derfred
Brercrow,
...
2. You must also agree that any other inertial frame of reference is defined as one that is moving at a constant velocity with respect to the first one (i.e. it is not being acted upon by an external force, so is not accelerating). True or False? ...
From his page on his "windward turn" theory (which is agreed by all to the simply the obverse of the downwind turn myth) :
When the wind is changing from one state of equilibrium to another, the air is accelerated and the air-velocity will change by a small amount (as in turbulence) causing changes to the aerodynamic forces.
In a uniform, constant velocity wind, the air *is* in equilibrium, it doesn't change to another state of equilibrium, and it is not accelerated, so the author fails in understanding the basic premise of his "theory". Alternately, the theory depends on flying within an accelerated air mass, which is a completely different scenario, and it was never disputed by anyone that energy gains can be achieved by crossing wind gradients. In either case, anything which follows is necessarily nonsense.