 The Tupolev Tu @-@ 12 ( development designation Tu @-@ 77 ) was an experimental Soviet jet @-@ powered medium bomber developed from the successful piston @-@ engined Tupolev Tu @-@ 2 bomber after the end of World War II . It was designed as a transitional aircraft to <unk> Tupolev and the VVS with the issues involved with jet @-@ engined bombers . 
