 As the anticipated enemy was the Soviet Union , the aircraft also required " <unk> " to allow them to operate from Arctic bases . The project included 36 B @-@ 29s , and the modification of 36 others to have an air refueling capability . With the addition of the 80 Saddletree B @-@ 29s , a total of 145 B @-@ 29s were modified to carry nuclear weapons , and 117 of these were assigned to operational units . 
