Power Predictor A 12m mast made using two 6m aluminium scaffolding poles. Watch the video:- http://www.youtube.com/watch?v=MF5rmF_0zYw Two 6m aluminium scaffolding poles (1.7kg/m) One joining piece to connect the two tubes end to end, One 4m steel pole (4.4kg/m) One clamp to attach it at 90 degrees to the aluminium pole. 10mm polypropylene ropes. 3 large stakes and 3 small stakes 1. A model was made using canes and string to prove the concept. 2. Aluminium poles were chosen -otherwise the mast would have been too heavy to lift. 3. A steel pole was used as the erecting lever, and its extra weight helped as a counterbalance. 4. Measure 12m diameter circle and marked stake positions at 120 degrees with one in the prevailing windward direction. 5. The three main stakes were driven into the ground at about 60 degrees to resist the tension. Wind Direction Colin Townend Teal Ltd 07825 702020 enquiry@tealweb.com 6. The site was checked for levelness so that all the rope lengths could be the same. 7. It was decided to tie one guy near the top of base pole, and 1/3 up the top pole so any single rope failure might be survived. 8. With the pole laid on the ground and a mark made 6m from its base to represent the stakes, the ropes were knotted to the mast and extended to the 6m mark in the ground. 9. A Rolling or Stopper Hitch or stopper hitch was chosen. http://www.tpub.com/content/armyengineer/en0562a/en0562a0171.htm http://www.proknot.com/html/rolling_hitch.html Stopper hitch http://www.tpub.com/content/administration/14067/css/14067_61.htm Colin Townend Teal Ltd 07825 702020 enquiry@tealweb.com 10. A tape marker was wrapped round each rope at the mark and then an extra 1.2m was added (for tying to the stake later) and the ropes cut. 11. The leeward side guy ropes were tied to the stakes using the tape markers to make them all the correct length. 12. Using a right-angle scaffolding clamp, the steel pole was fixed to the base of the mast. 13. The windward guys were temporarily tied to the lever arm together with a pulling rope. 14. Two small stakes on the windward side of the mast were used to guy the lever arm and keep it upright during pulling. (they would over-tighten on the leeward side). 15. The base of the mast was tied to an anchor stake to stop it being dragged when the lever was pulled. 16. A trial lift was made with only the bottom aluminium pole on its own. That allowed me to confirm that the bottom pole guy ropes were tied to the stakes at the correct length. 17. The top pole was then reattached with the clamp and the whole mast assembly was lifted 18. As the mast was pulled up into the wind, the slight cross-wing pushed the mast to one side tightening the guys and stabilising the pole. 19. Without that helping wind there would be a danger of the poles hinging in the middle. 20. Some helpers could make sure the guys were tight as the poles rose up, but more people mean more potential for injury. Perhaps making sure the wind is in the right direction is the key? 21. Once erected the guys were transferred from the lever arm to the windward stake, and all tensions were adjusted to straighten the mast. 22. Watch the video:- http://www.youtube.com/watch?v=MF5rmF_0zYw 23. The mast was erected on the 4th October 2010, it is still standing 20 months later and has recorded 16.5m/s (37mph) winds. 24. I have single-handedly raised and lowered the mast a couple of times to check the anemometer, and am now more confident that the mast is quite stable when lifted into the wind. 25. The clove hitches securing the guy ropes to the ground stakes are checked weekly and have needed tightening only once – after a gale. Colin Townend Teal Ltd 07825 702020 enquiry@tealweb.com Jan 2011. Colin Townend Teal Ltd 07825 702020 enquiry@tealweb.com