well what i do kno about the b-19 is that it was used as a cargo plane through out the war, o and the b-36 carried about 30,000 pounds BUT, the competition with the b-52 was the b-60 (all jet version of a b-36) carried about 80,000 pounds, which was 10,000 pounds more than the b-52!!!! they rejected it because it was slower though (i think)