▁possible ▁for ▁safe ▁land ings ▁on ▁Soviet ▁grass ▁air fields . ▁ ▁Const ruction ▁of ▁the ▁SK - 1 ▁was ▁of ▁light - al loy ▁str essed ▁skin , ▁with ▁single ▁plate ▁web ▁sp ar ▁wings ▁sk inned ▁with ▁light - al loy ▁sheet , ▁smooth ed ▁to ▁mirror ▁finish ▁accurate ▁profiles ▁using ▁mar quis ette ▁fabric , ▁c ork ▁dust , ▁open ▁we ave ▁and ▁ad hes ive ▁as ▁fill er . ▁Initial ly ▁the ▁wing ▁was ▁of ▁N AC A ▁ 2 3 0 1 4 . 5 ▁profile ▁with ▁sl otted ▁V las ov ▁style ▁f laps , ▁and ▁fabric ▁covered ▁a iler ons . ▁The ▁tail - unit ▁also ▁had ▁fabric ▁covered ▁control ▁surfaces , ▁and ▁trim ▁tabs , ▁with ▁all ▁controls ▁ 1 0 0 % ▁mass ▁bal anced . ▁ ▁The ▁M - 1 0 5 ▁engine ▁was ▁fitted ▁in ▁a ▁low ▁drag ▁installation ▁with ▁a ▁press ur ised ▁cool ant ▁system ▁which ▁required ▁a ▁radi ator ▁of ▁only ▁ 0 . 1 7 m ^ 2 ▁front al ▁area , ▁( approx ▁ ½ ▁that ▁of ▁a ▁similar ▁un press ur ised ▁cool ant ▁system ). ▁In ▁the ▁flush ▁co ck pit , ▁the ▁pilot ▁sat ▁on ▁a ▁hyd ra ul ically ▁actu ated ▁seat ▁which ▁raised ▁the ▁h ing ed ▁roof ▁of ▁the ▁can opy ▁to ▁form ▁a ▁wind - sh ield ▁for ▁landing , ▁allowing ▁the ▁fus el age ▁to ▁have ▁a ▁total ▁front al ▁area ▁of ▁only ▁ 0 . 8 5 ▁m