Notched spar to accept #1 ribs . Notched # 1 and # 2 ribs for straps. The number 1 ribs were time consuming, after marking the areas to be removed Iused a router to carfully relieve the areas. After this was done a seires of files were used to clean up the notches. The number 2 rib were seperated and a band saw was used to remove and clean up the notches.