Spooky 21's mission was covert but vital to the war. It was part of a secret combat operation known as Tiger Hound, a search-and-destroy mission aimed at the Ho Chi Minh Trail, a series of dirt and stone paths hidden in the Laotian jungle that served as an enemy supply line. It connected the communist North Vietnamese military with its allies in the Viet Cong insurgency hiding in the south.
Without the Ho Chi Minh Trail, said military historian James Willbanks, the war doesnt go on.
The AC-47 Spooky was the first in a series of aerial gunships developed to pour huge firepower down on ground targets during the Vietnam war.
Spooky was fearsome in fight. But scouring a jungle for targets in daylight, its big belly, slow turns and relatively low flight path could make it easy pickings for even simple Viet Cong air defenses.
The GAU-21 minigun
Three miniguns were mounted on the plane's left side; the pilot would "orbit" target in a left-banked circular turn while guns fired.
Each GAU-2A minigun could fire 6,000 rounds per minute. A three-second burst could cover a football field-sized area with a bullet every couple of yards. The plane carried a lot of ammo, about 24,000 rounds. But if things got hairy, the guns could burn through that in less than three minutes.
Image courtesy of the U.S. Airforce
Firing on ground targets
The call sign Spooky alluded to its ability to break Viet Cong night attacks on American bases. But among the Viet Cong it was nicknamed Dragon. Tracer rounds, especially at night, made it look like the plane was spitting fire at the ground.