math ▁Operation ▁Ke yst one ▁Card inal ▁concluded ▁on ▁ 2 7 ▁November ▁ 1 9 6 9 . ▁ ▁References ▁ ▁Ke yst one ▁Card inal ▁Category : Un ited ▁States ▁Marine ▁Corps ▁in ▁the ▁Vietnam ▁War ▁Category : B att les ▁and ▁operations ▁of ▁the ▁Vietnam ▁War ▁in ▁ 1 9 6 9 <0x0A> </s> ▁The ▁I MA M ▁Ro . 5 7 ▁was ▁an ▁Italian ▁tw in - eng ined , ▁single - se at ▁mon op lane ▁f ighter ▁of ▁the ▁Reg ia ▁Aer onaut ica . ▁Based ▁on ▁a ▁ 1 9 3 9 ▁design ▁by ▁Giovanni ▁Gal asso ▁the ▁aircraft ▁did ▁not ▁enter ▁production ▁until ▁ 1 9 4 3 . ▁ ▁Two ▁hundred ▁aircraft ▁were ▁ordered , ▁but ▁only ▁ 5 0 – 7 5 ▁were ▁produced ▁in ▁two ▁versions , ▁one ▁flow n ▁as ▁an ▁inter ceptor , ▁the ▁other ▁in ▁the ▁role ▁of ▁a ▁ground ▁attack ▁aircraft . ▁ ▁Design ▁and ▁development ▁ ▁The ▁Ro . 5 7 ▁was ▁preced ed ▁by ▁another ▁tw in ▁engine ▁f ighter ▁design , ▁the ▁Ro . 5 3 , ▁which ▁never ▁entered ▁production . ▁The ▁Ro . 5 7 ▁consisted ▁of ▁an ▁all - met al , ▁semi - mon oco que ▁fus el age ▁with ▁a ▁steel ▁ske leton ▁and ▁D ural umin ▁structure . ▁The ▁wings ▁were ▁also ▁D ural umin . ▁It ▁was ▁power ed ▁by ▁two ▁ ▁F iat ▁A . 7 4 ▁radial ▁engines ▁giving ▁a ▁maximum ▁speed ▁of ▁ 5 1