Heavy bombers

Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range of their era. Archetypal heavy bombers have therefore usually been among the largest and most well-powerful military or civil aircraft at any point in time. In the second half of the 20th century, heavy bombers were largely superseded by strategic bombers, which were often smaller in size, but were capable of launching nuclear weapons.

Because of advances in aircraft design and engineering – especially in powerplants and aerodynamics – the size of payloads carried by heavy bombers have increased at rates greater than increases in the size of their airframes. The largest bombers of World War I, the four engine types built by the Zeppelin-Staaken company in Germany, could carry a payload of up to 4,400 pounds (2,000 kg) of bombs. However, by the middle of World War II, even single-engine fighter-bomber could carry 2,000-pound (910 kg) bomb load and were taking over from light and medium bombers in the tactical bombing role. And advancements in four-engines enabled heavy bombers to carry even larger payloads to targets thousands of kilometres away. For instance, the Avro Lancaster (introduced in 1942) routinely delivered payloads of 14,000 pounds (6,400 kg) (and sometimes up to 22,000 lb/10,000 kg) and had a range of 2,530 miles (4,070 km). The B-29 (1944) delivered payloads in excess of 20,000 pounds (9,100 kg) and had a range of 3,250 miles (5,230 km). By the early 1960s, the jet-powered Boeing B-52 Stratofortress, travelling at speeds of up to 650 miles per hour (1,050 km/h) (i.e. more than double that of a Lancaster), could deliver a payload of 70,000 pounds (32,000 kg), over a combat radius of 4,480 miles (7,210 km).

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