The designation UH stands for “utility helicopter,” and no aircraft in the Vietnam War was more utilized than the Bell UH-1, the versatile workhorse known as the Huey.

The first Hueys arrived in Vietnam in the late 1950s to run medevac missions (called “dustoffs”) for American military advisors, but it didn’t take long for the Army to see the potential of the Huey as a new kind of war machine for a new kind of war. At Fort Benning, Army tacticians developed the concept of the “air assault,” a helicopter squadron of troop transports and gunships that could bring the battle to even the most remote location.

Unlike Korean War-era helicopters, which were powered by internal combustion engines, the Hueys and other Vietnam-era choppers had jet turbines (called turboshaft engines) powering their rotors, making them lighter, faster and much more powerful. As the war progressed, the Army ordered bigger Hueys for troop transport (known as “Slicks”) and attack-style Hueys equipped with joystick-guided missiles and heavy machine guns.

Mitchell says that the combination of troop-moving Slicks supported by a platoon of Huey gunships was a “match made in heaven.” With different models of Hueys performing specialized functions, the Army could send fully-armed troops directly into the combat zone protected by serious firepower.

Modified Hueys were effective as gunships, but they weren’t built for the job. Back at Bell headquarters, engineers reimagined the Huey as a true fighter aircraft. The result was the Bell AH-1G “Cobra,” better known in Vietnam by its nickname, the “Snake.”

The designation AH stands for “attack helicopter,” and the Cobra had the weaponry to back it up. The Cobra was flown by two airmen, like a World War II-era fighter. The pilot sat in the rear and could fire dozens of rockets from wing-mounted launchers. Up front, the co-pilot controlled a rotating “chin turret” armed with a minigun and a grenade launcher.

In an air assault, says Mitchell, the Cobras would race ahead—they could comfortably cruise at 120 knots, almost 140 mph—and lay down cover fire to clear the landing zone for the troop transporters. If a ground commander was taking enemy fire, he would “drop smoke” (a smoke grenade) and call in the Cobras to suppress the threat.

“You have to know that the ground guys loved the Cobras,” says Mitchell.

The designation OH stands for “observation helicopter,” but don’t let the name fool you; flying an OH-6 was the single most dangerous job in Vietnam. Nicknamed the “Loach” (for “light observation helicopters”), the OH-6 Cayuse was primarily a scouting aircraft that literally went “looking for trouble,” says Mitchell. “And if you go looking for trouble, you're usually going to find it.”

The OH-6 was deployed with AH-1 Cobras for what were known as “hunter-killer” missions. The Loach scouting helicopter would fly low over the jungle canopy looking for signs of the enemy. Loach pilots flew so low that they’d be able to spot fresh footprints or a burning cigarette butt in the brush below. They also frequently drew enemy fire and relied on razor-sharp reflexes (and luck) to avoid catastrophe.

Once the enemy position was spotted, the Cobra attack helicopters would swoop down and engage.

Next to the Huey, the twin-rotor Chinook is one of the most recognizable helicopters from the Vietnam War.

CH stands for “cargo helicopter” and the Chinook was built for hauling unprecedented payloads. The largest Chinook that operated in Vietnam had a gross weight capacity of 46,000 pounds. In the last days of the war, a single Chinook was able to evacuate 147 South Vietnamese refugees at once.

In combat, the Chinook could seat 55 troops and carry thousands of pounds of heavy weapons and supplies. It had a large, powered cargo door in the rear and doubled as a loading ramp for rapid loading and unloading of equipment and men.

The aptly-named Jolly Green Giant was the U.S. Air Force’s most advanced combat search-and-rescue helicopter. This specialized aircraft had to check two important boxes: be capable of flying long distances to reach stranded soldiers and be able to defend itself under heavy fire.

To extend its flight times, the Jolly Green Giant became the first helicopter capable of mid-air refueling. As for its combat specs, each Jolly Green Giant was equipped with two M60 machine guns, heavy armor, and a self-sealing fuel tank.

But perhaps the most recognizable feature of the Jolly Green Giant giant was its rescue hoist, which lowered intrepid rescuers to the ground, often under heavy enemy fire.

“Every helicopter pilot who flew in Vietnam had serious guts, but these were some really gusty dudes,” says Mitchell. “When you're down there trying to pull somebody out, you're a sitting duck.”

The twin-rotor Chinook was big and impressive, but even that oversized cargo hauler was only designated a “medium-lift” helicopter. For hoisting up really heavy payloads, like downed fighter jets and fully loaded shipping containers, the Army turned to the Sikorsky Skycrane.

The Skycrane had what’s known as a “stick” fuselage, meaning there was no internal cargo hold. When it wasn’t carrying external cargo, it looked like a giant, mechanical mosquito. But with six, 72-foot-diameter rotor blades and a hoist rated for 20,000 pounds, there wasn’t much that the Skycrane couldn’t lift.

“The Skycrane was primarily used to recover other aircraft,” says Mitchell. “If a helicopter or airplane was shot down in a rice paddy, they’d send in a DART team with a Skycrane and sling it back.”

In a nifty adaptation, the Skycrane could also lift a portable “personnel pod” with 90 men aboard.