In the mid 1960’s, the McDonnell Aircraft Company devoted some internal funds and effort to the F-4(FVS). This would have removed the wing from the F-4 Phantom II and replaced it with an all-new shoulder-mounted swing wing. The target of this enterprise was primarily the US Navy; MAC assured them that the F-4(FVS) would be a superior carrier plane to the standard F-4 due to better low-speed handling characteristics. However, while the design seems to have been pretty sound, by this point the Navy wanted a capability the Phantom couldn’t provide: Phoenix missiles. In the end, the Navy largely ignored the F-4(FVS) and went with the F-14. But even then, McDonnell-Douglas proposed a design for the F-14 contest, the Model 225A, that was in part derived from the F-4(FVS) studies.
A whole lot more about the F-4(FVS) and the Model 225 are in Aerospace Projects Review issue V3N4.
