Furthering my education via reading and attempting to understand new things
.......
In the foiling AC72 America's cup catamarans, the boats sail through the water at up to double the environmental wind strength. The effect of this is to radically change the apparent wind direction when sailing "downwind". In these boats the forward speed is so great that the apparent wind is always forward—at an angle that varies between 2 and 4 degrees to the wing sail. This means that AC72's are effectively tacking downwind, although at a greater angle than the normal 45-degree upwind angle, usually between 50 and 70 degrees.
Me too. But in the end, the salient point is that there's nothing "new" under the sun, and physics.
Fast boats have been running across the wind forever and from watching a modern cup even the angles haven't changed all that much.
zig
zag
zig
zag
If ways had been found which allow one to hew closer to the wind, it seems we'd see them. All this talk about pressure differentials and multiplication and apparent VS actual and reminds me of other discussions where because the descriptors include these phrases it's then assumed they're new or relevant when in fact they're included only because there's no better way to describe the action...... In simple fact, when a leaf tumbles downwind it's because it has "positive pressure" on one side and "negative pressure" on the other but the talk of MULTIPLYING or somehow using the wind twice is where the physics falls apart, where the physics professor took the bet.
Which he DID by the way..... and I'm sure even that rube of a professor had heard of boats going "faster than the wind"......
To "multiply" the wind one must present a mechanism which does so. Re-direction does not multiply, re-direction of the wind is just a way to modify direction, like moving money through different accts or transactions to clean it. This action changes the direction and character of the money but it doesn't
make money. Only a banana republic government can actually "make" money which of course then acts to drag down the system, just like in a boat.
The prop machine I linked in the op actually throws a new motive action into the mix which makes it DDFTTW. It could not be made to work on water or on ice. It cannot be made "more efficient" nor "faster" through tacking......And the salient point is that the dangling windflags actually reverse direction! the machine actually IS going Directly Downwind Faster Than The Wind! It uses the wind to generate enough velocity to experience a headwind!
And it shows a
mechanism which produces that velocity. Not magic, not reuse nor multiplying of force, a mechanism which uses a previously unused motive mechanism and puts it to good use.
The only "new" mechanisms presented in a Cup race are lowered drag due to foiling, lighter components due to availability of slightly higher strength composites, mainly cf and to a small extent computer modeling to test theoretical gains in a controlled environment. Actually SAILING and winning is still guts and seat-of-the-pants
