National Geographic : 1988 Sep
GLENNCURTISS, DOUGLASMCCURDY,BELL, FREDERICKBALDWIN, THOMASSELFRIDGE Lightweight but strong, the ings as gentle as a butterfly's. tetrahedron was the subject of The Aerial Experiment Associa countless experiments at Bell's tion (above) was formed in 1907 Nova Scotia home. His 70-foot to build a flying machine of observation tower of 260 tetra- each member's design. In 1909 hedral cells demonstrated the Douglas McCurdy's Silver Dart form's stability. Bell tested tet- flew halfa mile at 40 mph, the rahedral kites, seeking land- first airplaneflight in Canada.