▁division . ▁ ▁Design ▁and ▁development ▁The ▁S - 7 ▁was ▁two - se ater ▁wire - b rac ed ▁mon op lane ▁power ed ▁by ▁a ▁ ▁G nome ▁air - co o led ▁rot ary ▁engine . ▁Const ruction ▁began ▁in ▁early ▁summer ▁of ▁ 1 9 1 2 ▁and ▁completed ▁in ▁July . ▁The ▁pilot ▁sat ▁in ▁the ▁rear ▁co ck pit ▁with ▁a ▁passenger ▁se ated ▁in ▁a ▁forward ▁compart ment ▁in ▁a ▁tan dem ▁arrangement . ▁The ▁fus el age ▁was ▁en closed ▁in ▁p lywood ▁and ▁the ▁aircraft ▁used ▁components ▁taken ▁from ▁the ▁S - 6 A ▁including ▁the ▁main ▁wing , ▁tail ▁and ▁landing ▁g ear . ▁ ▁Oper ational ▁history ▁The ▁S - 7 ▁was ▁entered ▁in ▁the ▁international ▁military ▁competition ▁at ▁Saint ▁Petersburg ▁in ▁August ▁ 1 9 1 2 . ▁During ▁a ▁take - off ▁attempt ▁from ▁a ▁fur row ed ▁field ▁the ▁landing ▁g ear ▁was ▁sever ely ▁dam aged ▁and ▁the ▁S - 7 ▁was ▁unable ▁to ▁finish ▁the ▁completion . ▁In ▁ 1 9 1 3 ▁the ▁aircraft ▁was ▁rep a ired ▁and ▁served ▁as ▁a ▁tra iner . ▁In ▁ 1 9 1 4 ▁Bulg aria ▁purchased ▁the ▁S - 7 ▁and ▁used ▁it ▁in ▁operations ▁during ▁World ▁War ▁I . ▁ ▁Spec ifications ▁ ▁References ▁ ▁S - 7 ▁Category : Single - eng ined ▁tra ctor ▁aircraft ▁Category : M id - wing ▁aircraft ▁Category : A ircraft ▁first ▁flow n ▁in ▁ 1 9 1 2