The correct answer is the Republic XF-12 Rainbow. The XF-12 Rainbow was an American four-engine, all-metal prototype reconnaissance aircraft designed by the Republic Aviation Company in the late 1940s. Like most large aircraft of the era, it used radial engines—in this case, the Pratt & Whitney R-4360 “Wasp Major”. The aircraft was designed with maximum aerodynamic efficiency in mind. The XF-12 was referred to as an aircraft that was “flying on all fours” meaning: four engines, 400 mph cruise, 4,000 mile range, at 40,000 feet.[1]Although highly innovative, the postwar XF-12 Rainbow was fated to compete against more modern jet engine technology and was not to enter production.
The correct answer was submitted by intruder38, PontiacRich, and skybolt2003, thus continuing the tie. The third and final tie breaker for intruder38, PontiacRich and Skybolt2003 only will post shortly, so start studying, fellows! and thanks to all who participate (and send me great extra info!)
Brian [C):-)]