Heavy Bomber

A heavy bomber is a bomber aircraft of the largest size and load carrying capacity, and usually the longest range.

In New START, the term "heavy bomber" is used for two types of bombers:

• one with a range greater than 8,000 kilometers
• one equipped for long-range nuclear "air-launched cruise missiles" (ALCMs), defined as an air-to-surface cruise missile of a type flight-tested from an aircraft or deployed on a bomber after 1986.

The term was most commonly used prior to and during World War II, when engine power was so meager that bomber designs had to be carefully tailored to their missions. These sorts of distinctions were disappearing by the middle of the war, by which time the typical fighter aircraft could carry a 2,000 pounds (910 kg) load and light bombers were taking over roles and missions formerly flown by medium bombers.

Heavy bombers of the WWII era also were distinguished by their heavy defensive armament, for protection from smaller and usually much faster fighter aircraft. British designs often had three gun turrets with a total of 8 machine guns. U.S. heavy bomber designs, optimized for formation flying, had upwards of 10 machine guns and/or cannons in both powered turrets and manually operated flexible mounts to deliver the optimal protective arcs of fire. Positions for these guns included tail turrets, side gun ports which could be located either just behind the bombardier's clear nose glazing as "cheek" positions, or midway along the rear fuselage sides as "waist" positions, each with a .50 caliber machine gun), and dorsal (spine/top of aircraft) and ventral (belly/bottom of aircraft) gun positions with powered turrets. All of these machine guns enabled heavy bombers to defend themselves when they were beyond range of their fighter escorts, especially before the early 1944 introduction of the P-51 Mustang fighter design, starting with the Big Week bomber offensive. As the German Luftwaffe was primarily tasked with supporting the ground forces of the Wehrmacht, the Luftwaffe never had a chance to develop a heavy bomber before the start of the war - its prime proponent of strategic bombing, General Walther Wever had lost his life in a 1936 takeoff accident, with only the troubled Heinkel He 177 design existing as a frontline heavy bomber during the war years, which was used for only minor actions against both the Soviet Union and England.

The American innovation of the manned, ventrally-mounted Sperry ball turret on the B-17 and B-24 bombers was a virtually self-contained defensive weapon system that rotated a full 360 degrees horizontally with a 90-degree elevation, and its pair of M2 Browning machine guns had an effective range of one thousand yards. The B-29 Superfortress, introduced later in the war brought the innovation of four remotely operated twin-gun turrets on its fuselage, controlled through an analog computer sighting system sighted from any of a trio of hemispherical clear-glazed stations, with only the rear tail gunner position on the plane directly manned by a crewmember.

After World War II the term was used to describe some bombers dedicated to the strategic mission, but soon these were being referred to as strategic bombers, while smaller bomber designs with less range or load carrying capacity were called tactical bombers. The general utility of a manned heavy bomber has been greatly degraded not only by the advent of intercontinental ballistic missiles in the strategic role, but also with the introduction of more accurate precision-guided munitions ("smart bombs") which have greatly increased the efficiency of aerial weapons delivery; yet aircraft such as the B-52 Stratofortress and B-2 Spirit continue to fill a role and capability, when required of delivering tens of thousands of pounds of explosives per sortie.