The back-prop B-36, built after World War II, took its first flight August 8, 1946, during the start of the Cold War. It had a flying range of nearly 10,000 miles and could fly to Russia's Ural Mountains and back without refueling. Its combat range was 3,500 miles, enough to go from Maine to Leningrad, Russia without stopping. The B-36 had a distinctive sound very familiar to people in the Midwest as the plane was tested and flown. There were six piston-engine  propellers on the back of the wings and four small jet engines on the front. The B-36 was never used in wartime. References: Wikipedia, YouTube movie clip starring Jimmy Stewart (below).