The outrageously placed dorsal “Variable Area Inlet Duct” of the F-107A. This sophisticated variable geometry air intake was designed to automatically control the amount of air fed to the F-107A’s J75 engine. During the few test flights undertaken it proved to be troublesome, but…. Who cares?. The F-105 took it all.
Nice close-up pic of the second prototype lovely preserved at the National Museum of the U.S. Air Force.