DB - 1 M ▁vent ral ▁rem ot ely ▁controlled ▁tur rets ▁controlled ▁by ▁the ▁gun ner , ▁in ▁the ▁rear ▁of ▁the ▁crew ▁compart ment , ▁using ▁upper ▁and ▁lower ▁per is cop es . ▁ ▁The ▁prototype ▁was ▁completed ▁quickly ▁and ▁ready ▁for ▁flight ▁tests ▁by ▁late ▁ ▁September ▁ 1 9 4 8 ▁after ▁being ▁dis ass emble d ▁and ▁transport ed ▁to ▁Ty op ly ▁Stan ▁air field ▁on ▁the ▁out sk ir ts ▁of ▁Moscow . ▁The ▁first ▁flight ▁took ▁place ▁on ▁ 3 0 ▁September ▁ 1 9 4 8 , ▁but ▁early ▁test ▁fl ights ▁were ▁dis rupted ▁by ▁severe ▁problems ▁with ▁the ▁fuel ▁control ▁units ▁of ▁the ▁AM - T K R D - 0 1 ▁engines . ▁A ▁replacement ▁set ▁was ▁fitted ▁and ▁testing ▁continued ▁until ▁the ▁manufact urer ' s ▁tests ▁were ▁completed ▁on ▁ 2 4 ▁May ▁ 1 9 4 9 . ▁ ▁Council ▁of ▁Minister s ▁directive ▁No . ▁ 1 8 8 6 - 6 9 6 ▁called ▁for ▁development ▁of ▁ 1 4 0 ▁as ▁a ▁tact ical ▁reconna issance ▁aircraft ▁power ed ▁by ▁two ▁K lim ov ▁V K - 1 ▁cent rif ug al ▁flow ▁tur bo - jets . ▁During ▁the ▁design ▁work ▁for ▁the ▁' 1 4 0 - R ' ▁the ▁def ic ien cies ▁highlight ed ▁by ▁flight ▁testing ▁of ▁the ▁' 1 4 0 ' ▁were ▁addressed ▁as ▁well ▁as ▁the ▁addition ▁of ▁wing tip - mount ed ▁fuel ▁t anks