▁def ensive ▁arm ament ▁proved ▁to ▁be ▁less ▁than ▁fully ▁effective ▁due ▁to ▁the ▁in ade qu ate ▁power ▁provided ▁to ▁the ▁gun ▁mount s ▁by ▁the ▁gener ators , ▁and ▁the ▁de icing ▁and ▁light ing ▁equipment ▁were ▁in ade qu ate , ▁thus ▁restrict ing ▁the ▁aircraft ' s ▁operations ▁in ▁bad ▁weather . ▁ ▁T up ole v ▁made ▁un sol ic ited ▁propos als ▁for ▁variants , ▁including ▁the ▁Tu - 8 B ▁with ▁Mik ul in ▁AM - 4 2 ▁engines ▁and ▁the ▁Tu - 8 S ▁with ▁Char om ski ▁A Ch - 3 0 BF ▁dies el ▁engines , ▁but ▁none ▁were ▁accepted . ▁Soviet ▁military ▁pl ann ers ▁had ▁decided ▁to ▁dev ote ▁resources ▁to ▁development ▁of ▁jet ▁bom bers , ▁such ▁as ▁the ▁T up ole v ▁' 7 3 ', ▁which ▁were ▁already ▁flying , ▁and ▁which ▁exhib ited ▁much ▁more ▁potential ▁than ▁p ist on - eng ined ▁aircraft . ▁ ▁Vari ants ▁Tu - 8 ▁Initial ▁version , ▁power ed ▁by ▁radial ▁engines . ▁Tu - 8 B ▁Tu - 8 ▁power ed ▁by ▁Mik ul in ▁AM - 4 2 ▁inline ▁engines . ▁Tu - 8 S ▁Tu - 8 ▁power ed ▁by ▁Char om ski y ▁A Ch - 3 0 BF ▁dies el ▁engines . ▁' 7 2 ' ▁Jet ▁power ed ▁version ▁power ed ▁by ▁Roll s - Ro y ce ▁N ene ▁I ▁engines , ▁given ▁the ▁official ▁design ation ▁Tu - 1 8 ▁ 2