Hybrid Utility Pole / Pipe Wind Turbine Tower John Dailey c.1992 John Dailey Having purchased a Windseeker II wind electric turbine, we faced the daunting prospect of erecting a tower. The tower has to be at least 15 feet above surrounding obstacles. In our case this worked out to be 50 feet above the ground. Here are plans for a tower that is inexpensive, easy to build, and can be raised and lowered by a single person. Our Homestead Our homestead is located on the north side of the Alaska Range where the gusty and powerful Chinook winds are common. Any tower we built had to be rugged enough to withstand these high winds. The Tower and Tools and Safety This tower will support small to medium sized wind turbines. The tower consists of a 20 foot guyed utility pole with a three inch sleeve pipe U-bolted to the top. A smaller diameter pipe, with the wind turbine mounted on top, is winched up through this sleeve. The tower "telescopes" from full operating height to the partially-lowered maintenance position. You will need some common shop tools, including a good 1/2 inch drill, and a stout 24 foot extension ladder. Please wear a hard-hat and keep your wits about you while you work on the tower. Keep curious kids and loyal pets away. Always have an escape route planned, just as if you were felling trees, the forces and dangers are similar. Utility Pole Installation First, stake out the position of your tower and its three guy anchors. The anchors must be carefully placed at 120¡ intervals. The anchor locations must be at least 20 horizontal feet from the tower's base. If your site is not level, then make sure to place the guy anchor's ground position farther from the tower's base (if downhill) or closer (if uphill) to keep the guy wire at the same angle to the tower. In our case, earth augers are used to secure the guy wires to the ground. These earth augers have been used for decades by the phone companies to guy their poles. Screw the three augers securing the guys to the ground first, before you locate the utility pole. This allows for change in case you hit a big rock with one or more of the earth augers. Make sure you screw all the augers in deeply and securely. You don't want them pulling out; the success or failure of a tower is a digital event! If your soil is loose, or hardened bedrock, then earth augers are not appropriate and you must use concrete pads for the guy anchors. Be sure to use enough concrete, each pad will take at least 1/4 of a cubic yard of concrete. Excavate 16 inches deep for a concrete pad to support the utility pole. Don't skip the pad unless you have very firm substrata; vibration from the wind turbine will eventually break down even hard-packed soil. If the tower's base sinks, then the guy wires will become slack and ineffective. Dig a deeper next to the utility pole's base to set in a three foot section of three inch diameter ABS pipe. This ABS pipe will socket the tower's metal pipe when it lowered. Locate the ABS pipe next to the utility pole and radially midway between two of the guys. Bury the ABS pipe so its top is a few inches above grade. Pour a concrete pad at least 4 inches thick and throw in plenty of steel rebar. The downward force is considerable when the wind is blowing hard. Lay the utility pole out with its bottom near the concrete pad holding the ABS pipe. Drill holes and temporarily U-bolt the 3 foot long by 2 1/2 inch diameter sleeve pipe to the top of the utility pole. Mount the pulley block next to the sleeve and about two feet from the top of the utility pole. The pulley block should be bolted through the utility pole. Use heavy bolts and washers, don't use lag screws. Install the special eye-bolts, used to attach the guy wires to the utility pole, about four inches from the top of the utility pole. Tilt the pole up, and rotate it so that the sleeve pipe is directly above the ABS receiving tube. Tamp dirt around the utility pole's base to hold the pole approximately vertical. Clamp the 3/8 inch guy cables into the anchors and tighten the nuts on the angle eye-bolts to tension the guy cables and plump the pole. Tower Pipe Installation Loosen the U-bolts and remove the sleeve pipe from the utility pole. Insert the 21 foot long by 2 inch diameter lower tower pipe in the sleeve pipe. Screw a coupling on each end of the lower tower pipe. The winch cable will run outside the tower pipe. Drill through the lower coupling and attach the 30 foot winch cable with a cable clamp inside of the coupling. Tilt the tower pipe up against the utility pole and lower it into the ABS receiving tube in the ground. Then slide the sleeve pipe up the tower pipe and to the U-bolts. Clamp the sleeve pipe firmly to the utility pole with the U-bolts. Now prepare the 10 foot long by 2 inch diameter top section of tower pipe. Weld three half-rings 5 feet from the pipe's top, and double clamp the three 3/16 inch guy-cables to the half rings. Install the cable clamps only as shown the illustration to prevent weakening the cable. Make sure to loop the guy cable around the pipe, and through two of the half-rings. Neatly coil and tape the guy wires to the pipe. Take the pipe up the ladder and screw it into the coupling on top of the lower tower pipe. You might think it easier to join the two pipe sections earlier, but tilting up the shorter 21 foot section without a gin-pole is difficult enough; lifting the entire 31 foot length is impossible. INSERT GUY ART Using three spare cable clamps, temporarily tighten the upper guy cables before leaning the ladder against the upper pipe section. Then install the wind turbine on the upper pipe as per its manufacturer's directions. Mount the winch about chest-high on the utility pole, 90i from the tower-pipe/receiving tube axis. Thread the winch cable up through the pulley block on top of the utility pole, and down to the winch. Raising the tower for the first time can be tricky. Make sure that there is NO WIND and that none is even remotely expected. It is a good idea to have a helper on each guy cable to steady things as they rise. Winch the lower pipe up until the lower coupling is about 2 inches from the sleeve pipe's bottom. Then gently remove the slack from the guy cables and double clamp them. Now raise the tower pipe all the way up until the bottom coupling seats against the sleeve pipe. This last raise should tension the cables fairly tightly. You may have to readjust the cables so that the tower pipe is exactly vertical. Don't over tighten the guys; a few inches of lateral tower movement, under high wind, is OK. The three earth augers securing the guy wires to the ground provide a modicum of grounding. But these augers are no substitute for a good grounding system using copper wire and several ground rods. Finally, drill a hole through the utility pole underneath the bottom of the tower pipe coupling and insert a large bolt. Slacken the winch cable and rest the pipe sections of the tower on this bolt. Keep a small amount of strain on the winch cable, just in case this bolt fails. INSERT MATERIALS TABLE Operational Considerations When the wind turbine is in its lowered position, use a few spare clamps to temporarily guy the pipe before you lean the ladder on the top ten foot section. Make sure to winch the tower pipe up and down only during NO WIND conditions. If the sleeve pipe fits tightly enough, then helpers aren't need to raise and lower the installed tower. As the tower reaches full extension, the already adjusted guy cables tighten up and plumb the tower exactly vertical. To safely climb a ladder which leans only on a 2 inch pipe, we bolted a piece of 2X4 lumber to the top rung of the ladder. This 2X4 has a notch cut in it which fits the pipe. Access Author: John Dailey, HC 1, Box 3102A, Healy, AK 99743