. ▁He ▁is ▁trying ▁to ▁make ▁the ▁Wind b elt ▁che aper . ▁ ▁The ▁invent or ' s ▁claims ▁that ▁the ▁device ▁is ▁ 1 0 ▁- ▁ 3 0 ▁times ▁more ▁efficient ▁than ▁small ▁wind ▁tur b ines ▁have ▁been ▁ref uted ▁by ▁tests . ▁The ▁micro W ind b elt ▁could ▁generate ▁ 0 . 2   m W ▁at ▁a ▁wind ▁speed ▁of ▁ 3 . 5   m / s ▁and ▁ 5   m W ▁at ▁ 7 . 5   m / s , ▁which ▁represent ▁effic ien cies ▁( η C p ) ▁of ▁ 0 . 2 1 ▁and ▁ 0 . 5 3 ▁respectively . ▁ ▁Wind ▁tur b ines ▁typically ▁have ▁effic ien cies ▁of ▁ 1 % ▁to ▁ 1 0 %. ▁ ▁Since ▁the ▁Wind b elt ▁a ▁number ▁of ▁other ▁" flutter " ▁wind ▁har v ester ▁devices ▁have ▁been ▁designed , ▁but ▁like ▁the ▁Wind b elt ▁almost ▁all ▁have ▁effic ien cies ▁below ▁tur bine ▁machines . ▁ ▁Foot notes ▁ ▁References ▁ ▁Inst ru ctions ▁for ▁building ▁a ▁proof - of - con cept ▁wind b elt - power ed ▁lamp ▁with ▁parts ▁recovered ▁from ▁an ▁old ▁hard ▁drive ▁ ▁Wind b elt ▁cheap ▁micro ▁wind ▁generator ▁RE UK . co . uk ▁ 1 7 ▁October ▁ 2 0 0 7 ▁ ▁Wind b elt ▁- ▁rein vent ing ▁wind ▁power ▁physics . org ▁ 2 2 ▁April ▁ 2 0 1 0 ▁ ▁External