Republic XF-12 Rainbow

The Republic XF-12 Rainbow was a four-engined reconnaissance aircraft designed for the USAAF. Designed during the Second World War, the first of two prototypes had its first flight on the 4th of February 1946.

On the 10th of July 1947, the first prototype had its right main gear severed at the engine nacelle while landing during maximum load tests. The aircraft bounced and the pilot took the aircraft up to a safe altitude. During the resulting crash landing, the right wing spar was cracked and the two starboard engines needed replacing. Republic repaired the XF-12 and it was returned to service.

The second prototype crashed on the 7th of November 1948 when the port inner engine exploded, causing violent buffeting. Five of the seven crew escaped safely while two crew members were killed.

With the end of the Second World War and the introduction of jet aircraft, the USAAF lost interest in the project. When no orders were received, flight testing of the remaining XF-11 was wound down and ceased in 1952.

Republic proposed an airliner version of the XF-12, called the RC-2. Although tentative interest was shown by several airlines, the projected operating costs were higher than competing aircraft and no RC-2s were built.