this aircraft was a turboprop variant of the F-84F, this project actually arose becuase even in the 1950's people doubted that jet powered aircraft could take-off from a carrier, The XF-84H was an attempt to create a supersonic prop aircraft, though there was a lot problems mainly the aircraft was unstable due to torque, and its engine, the Allison XT40-A-1, was prone to failure, though the most well known problem was the fac that it's prop was actaully spinning at mach speed and it's shcokwaves could knock down people, the loud screeching noise the aircraft produced could make ground crews physically sick or in some case fainting, and it even gave an enginner a seziure after he was exposed to the shockwaves at close range, becuase of this it's often considered the loudest prop aircraft only rivaled by the Turpolev Tu-95 "Bear", it's sound was also enough to vibrate the windowns of the Edwards AFB control tower and hey actually forced Republic to do engine runs out on Rogers Dry Lake, though it never reached Mach speeds it was the fastest prop ever created