imer ▁for ▁Those ▁Who ▁Would ▁Govern ▁there ▁are ▁sketch es ▁and ▁a ▁photograph ▁of ▁a ▁model ▁of ▁the ▁K ite ▁Power ▁Station ▁from ▁the ▁Ober th ▁Museum . ▁▁ 1 9 7 7 ▁April ▁ 3 , ▁ 1 9 7 7 , ▁in vention ▁declared . ▁ ▁On ▁September ▁ 2 1 , ▁ 1 9 7 9 , ▁Douglas ▁S els am ▁not ar ized ▁his ▁k ite - l ift ed ▁end less ▁chain ▁of ▁air fo ils ▁H A WP ▁system , ▁generic ▁type ▁that ▁would ▁later ▁show ▁in ▁Dutch ▁astr onaut ▁W ub bo ▁O ck els ' ▁ ▁device ▁called ▁Lad der Mill ▁described ▁in ▁a ▁pat ent ▁of ▁ 1 9 9 7 . ▁Douglas ▁S els am ▁conce ived ▁his ▁Auto - orient ed ▁Wind ▁Har ness ing ▁Bu oy ant ▁Aer ial ▁Tr am way ▁on ▁April ▁ 3 , ▁ 1 9 7 7 . ▁On ▁the ▁S els am ▁not ar ized ▁dis closure ▁of ▁in vention ▁was ▁placed ▁a ▁date ▁of ▁Sept . ▁ 2 0 , ▁while ▁the ▁not ary ▁placed ▁the ▁final ▁signing ▁on ▁Sept . ▁ 2 1 , ▁ 1 9 7 9 . ▁notes ▁and ▁draw ings . ▁▁▁ 1 9 7 9 ▁Professor ▁Bry an ▁Roberts ▁begins ▁gir om ill ▁gy ro cop ter - type ▁H A WP ▁wind ▁generator ▁development . ▁▁ 1 9 8 0 ▁Mil es ▁Lo yd ▁publish es ▁an ▁article ▁on ▁the ▁cross wind ▁k ite ▁power . ▁▁