Step 4: Mast and Rigging for the Portable Wind Generator:
Designed to fully take advantage of gusting wind conditions, the wind generator has an unusually large tail fin, as well as a ball bearing fitting on top of the mast. This enables the unorthodox device to quickly seek out and turn into the next wind gust, with the flywheeling blades always ready to harvest the often erratic and meager winds. The large tail fin also stabilizes the device during furling, holding the wooden body straight-and-true, into the wind.
A lightweight, but strong, 24" long stainless steel mast-pivot tube was cannibalized from an extendable shower curtin rod, from a local hardware store. The tube is a sturdy thin-wall construction, internally butted with plastic sleeves on the ends, providing a low-friction pivot that slips perfectly over the 1" diameter fiberglass mast.
The generator, Aix-X blades, wooden mount, tail fin, stainless steel mast-pivot tube, and power cord all weigh in at 9-1/2 pounds, total, and mounts lightly on top of an extendable 10 foot tall fiberglass mast pole (actually a modified tree pruning pole), in perfect balance. 4 guy-lines and hardware mount complete the rig.
I have recently replaced the original 10 foot tall mast, with a 15 foot tall extendable fiberglass mast (also a tree pruning pole), providing much better wind exposure, but the rigging needed to be refined to handle the increased stresses on the mast:
- Four additional guy lines were attached to the mid-section of the mast and tied to the four original ground stakes.
- A ball&socket plastic water shut-off valve was modified into an articulated ball&socket base for the mast.
The setup of the portable generator and mast is now greatly simplified by the ball&socket base:
- A plastic stake is fully driven into the ground, for the mast. The stake is then carefully pulled out and the special, custom made ball-topped mast stake is pressed in its place.
- The looped end of a white nylon rope, with a red mark @ 13 feet, is slipped around the round shaft of the ball-topped mast stake, and the four anchor stakes are driven in, exactly 13 feet from the ball-topped mast stake.
- The non-looped end of the 13 foot white nylon rope is drawn taught and tied to the ground stake that is downwind (leeward) of the mast. This holds the ball-topped mast stake firmly in place for the set-up and take-down side stresses that will follow.
- The 15 foot mast is fully extended, with its internal wire connected to the wiring of the wind generator. The wind generator is then slipped onto the top of the mast.
- The socket base of the mast is snugged onto the ball of the ball-topped mast stake.
- The upper rigging (4 guy lines) is attached to the mast, and 3 of the guy lines are attached to the ground stakes EXCEPT the 4th guy line that is upwind (windward) is NOT attached to its ground stake.
- Firmly grasping the 4th guy line, standing above the upper mast anchor, gracefully pull up the wind generator and mast, while walking back into the wind, and attach the 4th guy line to its ground stake.
- The entire rig will now be in its vertical, perpendicular, position and requiring only minor adjustments.
- Attach the lower 4 guy lines to both the lower mast fixture and ground stakes. Carefully tension all 8 guy lines until the slender, flexible mast is straight and true.
- Take-down of the wind generator / mast is simply the reverse of the above.
The generator, from shaft arbor tip to tail, measures 45 inches. The power cord is routed through the ring-shaped ball bearing fitting, and inside the hollow, fiberglass mast. A standard RCA audio jack, used as an electrical connector, slips easily through the 5/8" diameter hole in the ball bearing fitting of the mast and down through the hollow mast. A slip ring (rotating electrical connection) is not needed, as a portable wind generator only pans a total of about 270 degrees, on a typical day.
The rigging attaches to a square piece 5" x 5" plywood, 11/16" thick, and glue mounted (PVC glue bonds well on both surfaces) to a PVC pipe which slips over the 1" diameter fiberglass mast. A thumbscrew tightened ring was fitted over the radial-cut end. 4 angled, thin plywood braces will later be added to the underside of the 5" x 5" plywood, for reinforcement.
The 4 guy-lines are firmly anchored into the ground with 17" long, heavy, steel "cork-screw" stakes.
The entire rig is easily set up and taken down by one person.
A side note:
I was recently invited by a local ham radio club to set up my portable wind generator, for their international ham radio day. I was quite impressed with their portable 24 foot antenna masts, made from interlocking U.S. military surplus antenna mast poles. These sturdy (2 lbs each), inexpensive, 4 foot long composite (resin impregnated glass fiber) mast sections can be purchased on ebay. The mast sections have an outside diameter of 1-13/16", an 1/8" (.125") wall thickness, with a 3.5" long male/female coupling end.
Also, standard military surplus composite 4-point guy line attachment rings can be purchased, which slip on easily between any of the 4 foot section joints. The guy ring is 5-11/16" diameter, drilled with four 3/8" guy line holes, with a 1.531" diameter center hole.
These pole sections not only allow for taller and stronger portable wind generator masts, it also makes the reality of truly portable 500 watt (500 watts rated = 75 watts typical) wind generators not only possible, but much simpler and affordable.