Gigantic Airborne Transport Helicopters: Revealing the World’s Biggest

Throughout history, significant advancements in both medical and technological fields have frequently surfaced during periods of conflict, particularly in times of war. Notable examples include the development of jet fighters and advancements in medicine, among others. Moreover, the demand for large aerial transporters arose primarily during a distinct type of conflict: the Cold War.

At the beginning of the Cold War, in the Soviet Union, the Red Army asked the aviation bureaus to develop a heavy lifter—something that could carry troops and impressive loads so they could be quickly deployed in a combat zone. The Mil OKB – Opytnoe Konstructorskoe Byuro (Experimental Design Bureau in Russian) came up with an unusual rotorcraft. It could lift up to 6 tonnes, and it proved to be what the Soviet commanders had asked for. The project was green-lit on June 1st, 1955, and the final product was named Mi-6. In just two years, on June 5th, 1957, the first production model took off. It was the first turboshaft-powered helicopter developed in the Soviet Union. Thus, the competition for producing bigger, more powerful rotorcraft began, and the Western Allies entered the game.

So, here is a list of the most powerful rotorcraft created by masterminds of aviation in their pursuit to develop aircraft able to take off with a maximum weight of at least 10,000 kilograms (22,046 pounds).

1. Boeing Vertol CH-46 Sea Knight

Boeing was the first to deliver when the U.S. Marine Corps asked, in 1961, for a medium assault helicopter. Thus, in 1964, the first twin-turbine tandem-rotor CH-46A Sea Knight took off and entered service a year later in Vietnam. It was tasked to transport troops and materials, supporting the U.S. Army.

Thanks to its tandem-rotor system, the Sea Knight, also known as the “Phrog,” proved worthy in adverse meteorological conditions. It could withstand crosswinds and land on moving ships. It was powered by a pair of General Electric T58-GE-16 turboshafts that developed 1,879 shp (shaft power). It’s 45 feet (13.92 meters) in length and was lifted by the two 51-foot (16 meters) diameter rotors. Since its maximum takeoff weight was 24,300 pounds (11,000 kg), it is at the bottom of our list. But we can’t ignore its abilities and long, successful history.

2. Aérospatiale SA 321 Super Frelon

Sud Aviation was one of the most important helicopter manufacturers in Europe. The French company is responsible for many outstanding successes. But in our list, it’s brought with the SA 321 Super Frelon (Hornet in French).

On December 7th, 1962, the big French hornet took its maiden flight powered by three Turbomeca IIIC Turboshafts that developed 1,550 shp each. The production version entered service in 1966, but not before establishing a world speed record for helicopters. In July 1963, a modified version of this French bird was clocked at 217.7 mph (350.4 kph). Remember, folks, this is a transport helicopter. In the real world, it’s like the fastest semi on the road. Considering that it’s a 76-foot (23.03 meters) long aircraft with a 62-foot (18.9 meters) rotor diameter. Moreover, this beast could land on water, and it was produced in over 100 units. It was sent to a well-deserved retirement in 1981 from the French Army. It was also produced, under license, in China.

3. Sikorsky CH-54 Tarhe

American helicopter manufacturer Sikorsky was not far behind, though, and on May 9th, 1962, the CH-54 Tarhe made its maiden flight. In case you’re wondering where the “Tarhe” name comes from, it is from an Indian chief who had this name. His nickname was “The Crane.” Just like him, the CH-54 was built to be a sky-crane. It was mainly used as a recovery helicopter, but it could also carry a large, 15,000-pound (6,800 kg) bomb. In addition, it proved useful in delivering command posts, army hospitals, and barracks to the front lines.

The CH-54 Tarhe was powered by a pair of Pratt & Whitney T73-P-700 turboshaft engines that delivered an astonishing 4,800 shp. This giant helicopter was 88.6 feet (27 meters) long, and its main rotor was 72 feet (22 meters) in diameter. The CH-54 Tarhe made it to our list due to its maximum takeoff weight of 47,000 pounds (21,000 kg).

4. Boeing CH-47 Chinook

In the aviation world, the Chinook is as known as the Wrangler is in the off-road vehicles communities. Maybe its shape with tandem rotors might be confused with the CH-46 Sea Knight, but so is the Wrangler with its various generations. In addition, it is very popular and can serve many purposes, from heavy-lift transportation to carrying troops on board. Moreover, it proved its efficiency during disaster relief, search and rescue operations, firefighting, heavy construction, and others.

While the Navy needed a medium chopper, the Army asked for a heavier transport one. Thus, the first Chinook took to the skies in September 1961 and entered service the following year. The first of its kind, the CH-47A Chinook, had its maiden flight in August 1962. With a maximum takeoff weight of 33,000 pounds (14,969 kg) and a payload of 10,000 pounds, it clearly deserves a place on our list.

But we want to talk about the D version, which was, at the time of launch, the weightlifter of the family. It could take up to 26,000 pounds (12,000 kg) hung under its belly and had a maximum takeoff weight of 50,000 pounds (22,680 kilograms). The triple-hook system was crucial for payload stability, and that made it capable of carrying 155 mm howitzers with a speed of up to 161 mph (260 kph). It was not a small aircraft either. It measured 98.10 feet (30.1 meters) in length, and its rotors were 60 feet (18.3 meters) in diameter. Due to its size, it could carry up to 55 troops beside the flight crew. The CH-47D was powered by two Lycoming T55-GA-712 turboshafts, each outputting 3,750 shp.

5. Bell Boeing V-22 Osprey

Not a helicopter per se, the Bell Boeing V-22 Osprey takes off and lands like a helicopter, but travels like an airplane, its engine nacelles converting it into a turboprop high-speed, high-altitude aircraft. According to Bell Boeing, the Osprey can carry 24 combat troops, or up to 20,000 pounds (9,072 kilograms) of internal cargo or 15,000 pounds (6,804 kilograms) of external cargo, at twice the speed of a regular helicopter. It features a cross-coupled drive system, so either engine can power the rotors if one engine fails.

For shipboard compatibility, the rotors fold, and the wing rotates to minimize the aircraft’s footprint for storage. The V-22 tiltrotor aircraft is the only vertical lift platform capable of rapid self-deployment to any theater of operation worldwide. The Osprey is powered by two Rolls-Royce T406-AD-400 turboprop/turboshaft engines, each with a whopping output of 6,150 hp. The rotors have a 38 feet (11.6 meters) diameter, and the total length of the aircraft is 57.14 feet (17.5 meters). With its maximum takeoff weight of 60,500 pounds (27,400 kg), the tiltrotor aircraft made it to our list. It can lift up to 20,000 pounds (9,070 kg) of internal cargo or up to 15,000 pounds (6,800 kg) of external cargo.

6. Sikorsky CH-53E Super Stallion

Based on the CH-53 Sea Stallion, the Super Stallion is currently the largest and heaviest chopper in the U.S. military inventory. With an internal payload of 30,000 pounds (13,600 kg) and external of 32,000 pounds (14,500 kg), the Sikorsky CH-53E Super Stallion is the only helicopter that can lift the 155 mm howitzer complete with crew and ammo. Moreover, it can lift an aircraft as heavy as itself.

Powered by three General Electric T64-GE-416/416A turboshafts, each rated at 4,380 shp, with a length of 99 feet and 1/2 inch (30.2 meters) and a rotor diameter of 79 feet (24 meters), the Hurricane Maker (a nickname resulted from the downwash it generates) has a maximum takeoff weight of 73,500 pounds (33,300 kg).

7. Mil Mi-6

The chopper that started this heavyweight lifting championship would fit in our fourth place, even if it was designed in the late ’50s. With the NATO codename “Hook,” the Mi-6 is said to have entered production in 1960, with some 860 units having been built until 1981. When it first flew, the Mi-6 was the world’s biggest operational chopper. It was also the USSR’s first turboshaft helicopter. Even so, the Mi-6 won the Sikorsky trophy in 1961 as the first helicopter to exceed 186 mph or 300 kph in level flight.

Powered by two Soloviev D-25V turboshafts with a combined output of 11,000 shp, with a staggering rotor diameter of 114 feet and 10 inches (35 meters) and a length of 108 feet and 10 inches (33.18 meters), the Mi-6 had a maximum takeoff weight of 93,700 pounds (42,500 kg) and an internal cargo capacity of 26,400 pounds (12,000 kg) of internal cargo. It could carry up to 90 passengers or 70 fully-equipped airborne troops.

8. Mil Mi-10

Developed in 1962 and based on the Mi-6, the Mil Mi-10 has a maximum takeoff weight of 96,340 pounds (43,700 kg). Though without a big difference in maximum takeoff weight from its predecessor, the “Harke” (NATO codename) has a payload on the platform of up to 33,070 pounds (15,000 kg) or a 17,635 pounds (8,000 kg) max slung payload.

As noted here, while the Mi-6 and Mi-10 shared the same engines, transmission, hydraulic system, and rotor system, the latter featured a cut-down fuselage designed mostly for passenger accommodation and without the required internal clearance or large loading doors for bulky loads. The Mi-10 had large external fuel tanks and wide-track, four-legged, extended landing gear to allow the big helicopter to straddle bulky cargoes.

9. Mil Mi-26

Though not the biggest helicopter in history, the Mi-26 (NATO codenamed “Halo”) stands as the largest and most powerful rotorcraft ever to reach the assembly line. Introduced in 1983 and still in production, the Mi-26 is powered by two Lotarev D-136 turboshafts with a combined output of 22,480 shp and has a maximum takeoff weight of 123,500 pounds (56,000 kilograms). It can transport payloads of up to 44,000 pounds (20,000 kg) for distances of up to 497 miles (800 kilometers).

The Mi-26 has a standard crew of four, including a pilot, copilot, navigator, and flight engineer. The cockpit side windows are bulged to improve visibility. Three video cameras are fitted to check the load during flight. The cockpit is pressurized, though the cargo bay is not.

10. Mil Mi-12

Here we are at the top of our list, with the world’s largest helicopter in the world, a record held, of course, by the Russians with this unconventional flying contraption.

Though the Mi-12 never made it to production, two prototypes were built. The first flight took place in 1968 and made its public debut in 1971 at the Paris Air Show. Codenamed “Homer,” the Mi-12 used a side-by-side rotor scheme, each rotor being powered by a pair of Soloviev D-25VF turboshafts, each outputting 5,500 shp, for a total output of 22,000 shp.

With a length of 121 feet and 4 inches (37 meters) and a rotor diameter of 114 feet and 10 inches (35 meters), the Mi-12 has a maximum takeoff weight of 231,500 pounds (105,000 kg) or 231,500 pounds and holds the payload record with 88,636 pounds (44,205 kg).

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