The development of the B-36 was triggered by Nazi Germany's aggression and subsequently by the Japanese attack on Pearl Harbor. The Army Air Forces (AAF) required a long range bomber to carry the war to the enemy: Despite the sense of urgency, the B-36 program progressed slowly. Existing technology failed to satisfy the military requirements of 1941, early wartime demands exceeded materials, and weapons more readily available received the highest priority during the war.
Military setbacks in 1942 led the AAF to concentrate on the Boeing B-29 (under production order since September 1941) at the expense of the B-36. However, growing concern in the spring of 1943, as China appeared near collapse, reversed the situation. Believing the B-36 might be the only bomber capable of attacking the Japanese homeland, the AAF called for 100 production model B-36s. Meanwhile, the contractor continued to struggle with various development troubles, serious engine problems, and significant weight increases. In mid 1944, engine problems reached a climax. Still, Convair's request for consideration of another engine was ignored because of the cost, time involved, and technical unknowns. In any case, the military position was no longer critical after the capture of Pacific bases and the deployment of the B-29, which would ultimately devastate Japan's home islands.
Yet, the B-36 did survive in the postwar environment. The United States Air Force (established as an independent service in September 1947) needed a long range aircraft to carry the atomic bomb, and to further its claim on the atomic mission.
Driven by six engines, it had a 3,740-nm combat radius with a 10,000-pound payload, or a 1,757-nm radius with a maximum bomb load of 86,000 pounds. Unwieldy planes with a wingspan of 230 feet, a length of just over 162 feet, and a height of nearly 49 feet, the B-36 had an official range of 10,000 miles. Actual range for the bomber was 6,800 to 8,175 miles, with aerial refueling required. When loaded, the B-36 burned fuel at an exorbitant rate.
As the cold war intensified, deterrence through fear of atomic retaliation became the linchpin of American national security policy. Until air refuelable, jet powered bombers were operational, only the B-36, with its vast bombload capacity, could strike the Soviet Union, America's previous ally and now potential adversary. No matter the cost in effort or money, the B-36 had to be made to work. Just the same, the B-36 required technical innovations that were beyond the state of the art. The experimental flight of August 1946, nearly 6 years after signature of the development contract, confirmed that the new bomber was underpowered. Improvement of the original R-4360 engine yielded little relief, and Convair's attempts to fit the engine with a variable discharge turbine failed. In 1949, the engine problem was somewhat alleviated by mounting turbojets under each of the B-36's wings. Still, throughout its entire operational career, the B-36 heavy bomber remained too slow, a shortcoming that increased its vulnerability and necessitated the protection of escort fighters.
In the early fifties, after modification of the landing gear, correction of the electrical system, and elimination of fuel tank leakages, the first B-36 remained highly troublesome. Other production models were not faring much better: the gunnery system was operationally unsuitable, the defensive armament was poor, and its fire control system was barely adequate. At long last, in 1954, so called "Featherweight" B-36s came into being. Whether new or reworked production models, the Featherweights proved fairly problem free. The B-36s were also used for reconnaissance and served effectively. Perhaps the aircraft's most important contribution, though impossible to measure, lay in deterring a general war during the difficult years of its active life.