Pulling on a wire spool

Demonstration of a concept that comes into play in one of the DDWFTTW (directly down wind faster than the wind) designs. The spool is propelled by the tension in the wire, yet it moves faster than the wire is moving. If the spool had vanes on the lower surface of its core that could be feathered during the trip around the top, it would be able to move DDWFTTW. The key is that the lower surface of the core is moving forward more slowly than the hub, so it can feel a tailwind even when the hub (and thus the spool as a whole) is outrunning the wind and feeling a net headwind.

• Category

  Education

[K.H. Weiss]

So, this wokrs only as long as there is a good amount of friction between the spool and the ground. This would not work on ice I assume? This would work less well on a not smooth surface? Even with a floating paddle wheel spool This would not work in water?

[jjcote]

Same answers as to whether a bicycle would "work" in various situations. Not well if it's slippery, and a rough surface would depend on the tires. With a floating spool, if the wheel was light enough to float high in the water (styrofoam construction?), then it will depend on whether the core diameter is small enough.

[brkfstclub35]

Thank you for this demonstration! When pulling heavy gauge wire off spools, some electricians choose to pull the wire off from the bottom of the spools. Your demonstration proves there is less resistance when pulling wire from the "top" of the spool. Thanks!