In 1898, Bell experimented with tetrahedral box kites and wings constructed of multiple compound tetrahedral kites covered in maroon silk.[N 23] The tetrahedral wings were named Cygnet I, II and III, and were flown both unmanned and manned (Cygnet I crashed during a flight carrying Selfridge) in the period from 1907–1912. Some of Bell's kites are on display at the Alexander Graham Bell National Historic Site.
Bell's kits were flown from 1907 to what year?
1912