 It never progressed beyond a wind tunnel model, and performance, range and dimensions here are based solely on the designers' estimates.The master aircraft designer Ernst Heinkel himself remarked in October 1943, while both designs were still being worked on, that he thought that only the Ta 400 could be a worthy competitor to his firm's He 277, for the Amerika Bomber competition.The Ta 400 was essentially a backup design for the Messerschmitt Me 264.