When the B-52 was originally conceived, its express purpose was the delivery of nuclear weapons against the Soviet Union. However, America's Cold War interventions had other plans for the venerable aircraft.
As America's role expanded in Vietnam, so too did the B-52's.
This came in the form of Operation Arc Light — the initial deployment of B-52's from the United States to Guam to support missions in Vietnam. These bombers, in the B-52's combat debut, first struck North Vietnamese targets in June 1965 using standard 750 and 1,000 pound bombs.
The B-52's expanded role led the Air Force to modify numerous existing B-52D models under a program called Big Belly. This modification turned the B-52 into an absolutely devastating conventional bomber.
A U.S. Air Force Boeing B-52F Stratofortress drops bombs over Vietnam. (U.S. Air Force photo))
The improvements allowed the B-52 to carry 84 500-pound bombs internally as well as another 24 750-pound bombs mounted on wing pylons. This gave the bomber a total of 108 bombs or 60,000 pounds of bombs to drop on the enemy.
By comparison, the B-17G, America's bombing workhorse of WWII, could only carry about 9,600 pounds of bombs on missions.
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When flown in a pair of cells — or a group of three B-52s in formation — the bombers could leave behind a swath of destruction a mile long and a half mile wide.
In addition to the B-52's massive bomb load, it was especially effective for another reason: ground-directed bombing.
Air Force technology had come a long way since the days of carpet-bombing the Third Reich and Imperial Japan. This meant that the destruction the B-52s could be brought to bear was much more accurate than ever before.
B-52D hailing 500-lb bombs. (Image: Wikimedia)
This was accomplished using Combat Sky Spot, an interlinked system of radar sites, utilizing the MSQ-77 radar/computer system, to accurately direct bombing missions.
These sites were manned by airmen of the Combat Evaluation Group. With numerous sites located throughout the region, they provided guidance across the entire battlefield.
The MSQ-77, or Miscue 77 as it was often referred to, was revolutionary because it used an algorithm to determine exact bomb impact points, rather than specific release points for aircraft as earlier versions had done.
This meant that bombers and fighter-bombers operating at night, in bad weather, or near friendly troops could be directed to where their bombs would land.
This level of accuracy meant that large scale bombing runs could safely be made within 1,000 meters of friendly forces, closer with the approval of a Forward Air Controller.
This ability would be used to devastating effect against the North Vietnamese in numerous battles.
During Operation Harvest Moon, the Marines used the giant B-52 bombers against stubborn Viet Cong resistance.
The B-52s also helped the 1st Cavalry Division troopers fighting in the Ia Drang.
The B-52 and the 70,000 pounds of munitions it can carry. Photo: U.S. Air Force
By 1966, B-52 bombers flew over 5,000 missions against targets in Vietnam, accounting for more than 8,000 tons of bombs per month. Besides just supporting ground troops the bombers also flew interdiction missions against North Vietnamese convoys on the Ho Chi Minh Trail.
By 1967, the number of Arc Light missions had nearly doubled with most missions being in direct support of troops in contact.
In 1968, Arc Light B-52s flew numerous close air support missions in support of the Marines under siege at Khe Sanh. Flying high above the monsoon rains that had grounded the fighters, and aided by the MSQ-77, the B-52s put 60,000 tons of the proverbial warheads on foreheads.
This round-the-clock punishment helped to break the siege.
Because the B-52s flew so high as to remain unseen and unheard by the enemy, they had to find other ways to counter. This meant the men of the Combat Evaluation Group at the Combat Sky Spot sites were the most likely target.
The North Vietnamese realized if they could take out the radar sites then they could impair American bombing efforts. This led to the largest loss of airmen on the ground when the North Vietnamese overran Lima Site 85 and took out its Combat Sky Spot.
Despite the dangers to all involved, the Arc Light missions were a great success and continued through the end of the war.