Republic XP-47H Thunderbolt.
The Thunderbolt was the most numerous American fighter ever built, but the H model was not the familiar "Jug" that fought in every theater of World War II. A colossal Chrysler XI-2220-II inverted-V 16-cylinder liquid-cooled, in-line engine--rated at about 2,300 horsepower--powered this version of the Thunderbolt.
Two aircraft were covered by this contract (serials 42-23297 and 42-23298). The Chrysler powerplant changed the appearance of the Thunderbolt considerably, but Republic's famous fighter was being used only as a test bed for the engine. The Army Air Forces never seriously contemplated manufacturing a version of the Thunderbolt with this arrangement.
According to Roger Freeman, in Thunderbolt: A Documentary History of the Republic P-47, the two XP-47H airplanes began on the Evansville, Indiana, production line as P-47D models. Freeman wrote that creation of the H model entailed redesigning the aircraft forward of the firewall, with new duct work to the General Electric CH-5 turbosupercharger and modifications to associated equipment, including intercooler outlet doors. The XP-47H used a thirteen-foot, four-bladed Curtiss Electric propeller.
Construction of the XP-47H took longer than planned. The first ship made its initial flight at the Evansville factory on July 27, 1945. By then, the United States was on the verge of canceling dozens of aircraft contracts. Fighting ended less than three weeks after that maiden flight.
Chrysler continued developmental work on the XI-2220 and another, even larger, engine well into the postwar years. Very little has been published about how the XP-47H contributed to this effort but, in the end, no production engine ever reached Air Force units.
Our follow-up photo, obtained from Republic in the 1950s, shows the first XP-47H running up on the ramp at Evansville.
Twenty-one readers sent in "History Mystery" postcards. All identified the XP-47H correctly.
Our History Mystery. winner is Roland Plante of Bettendorf, Iowa. Roland receives a copy of the book Air Force One, by the author of this column. Copies of the book are available from Bob at firstname.lastname@example.org