 The Joint Chiefs of Staff issued a directive in January 1948 for the modification of 225 B @-@ 29 , B @-@ 50 , and B @-@ 36 bombers to carry nuclear weapons , along with eight C @-@ 97 Stratofreighter aircraft to carry bomb assembly teams . There were already 32 Silverplate B @-@ 29s in service with the Strategic Air Command , so the Air Materiel Command was directed to carry out Saddletree modifications on a further 80 B @-@ 29s , 36 B @-@ <unk> , 23 B @-@ <unk> and 18 B @-@ <unk> . The B @-@ 36A could not carry nuclear weapons without major modifications . 
