The Largest Transport Helicopters in the World
The place is Russia and the time is the early years of the Cold War. The task was to build a rotorcraft with a big load carrying capacity. Military tactics of the 1950s were studied and the conclusion was that a heavy transport and troop-carrying helicopter capable of airlifting combat materiel weighing up to six tonnes (13,228 lb), such as artillery pieces with tractors, heavy trucks and self-propelled guns for the airborne assault troops, was necessary. At the end of 1952, the Mil OKB - Opytnoe Konstructorskoe Byuro, meaning Experimental Design Bureau - had the first versions of the VM-6 (Vertolyot Mil’a - Mil’s helicopter, load-carrying capacity 6 tonnes) prototype ready.
On June 1st 1955, the Government Commission gave the go-ahead for the full-scale mock-up of what will be known as the Mi-6, the biggest chopper at that time. Two years later, the Mi-6 was doing its first run with R. I. Kaprelian as test pilot, thus opening a new chapter in aviation history.
And that’s the subject of this week’s coverstory in which we will get more acquainted with the top ten biggest transport choppers in history, meaning flying monsters with the maximum takeoff weight of over 10,000 kilograms or 22,046 lb. Because we want to save the best for last, we will list the helicopters in ascending order of their maximum takeoff weight.
10. Boeing Vertol CH-46 Sea Knight
The twin-turbine tandem-rotor CH-46A Sea Knight was the result of a design competition for a medium assault transport helicopter for the Marine Corps in 1961. The first U.S. Marine Corps Sea Knight was delivered in 1964 and began military service during the Vietnam War a year later. Its task was to carry troops and cargo to and from Navy ships in the China Sea.
Known as the “Phrog”, the Sea Knight was said to benefit from increased agility and superior handling qualities in strong relative winds from all directions thanks to its aforementioned tandem-rotor design.
Powered by two General Electric T-58-GE-16 turboshafts, each developing 1,400 kw or 1,870 shp, with a length of 13.92 meters or 45 ft 8 in and with a rotor diameter of 16 meters (51 feet), the Boeing Vertol CH-46 Sea Knight has a maximum takeoff weight of 11,000 kilograms (24,300 lb), making it the lowest capacity chopper in our classification.
9. Aérospatiale SA 321 Super Frelon
The only French rotorcraft on our list, the Aérospatiale SA 321 Super Frelon (which by the way stands for “Hornet” in French) is a three-engined flying machine manufactured by Aérospatiale of France. Powered by three Turboméca Turmo IIIC turboshafts, each outputting 1,171 kW (1,570 hp), the SA 321 Super Frelon has a maximum takeoff weight of 13,000 kilograms (28,660 lb). Other specs include a length of 23.03 meters (75 ft 6 5/8 in) and a rotor diameter of 18.9 meters (62 ft).
8. Sikorsky CH-54 Tarhe
Named after a remarkably tall Indian chief who lived between 1742 and 1812, the Sikorsky CH-54 Tarhe had its first flight in 1962 and was intended for the United States Army. As mentioned here, the CH-54 was used in aircraft recovery operations when loads were too heavy for the classic CH-47 Chinook. Apart from the universal pod that could be attached to the fuselage, the CH-54 could also be rigged to drop a large 10,000 lb. cratering bomb to create landing zones in dense jungle. The said pod was quite versatile, being able to work as a mobile command post, maintenance and repair shop or as a Mobile Army Hospital (MASH).
Also available for civil purposes, the Sikorsky CH-54 Tarhe is powered by two Pratt&Whitney T73-P-700 turboshaft engines, each outputting 4,800 shp (3,580 kW). With a total length of 26.97 meters or 88 ft 6 in and a rotor diameter of 21.95 meters (72 ft), the helicopter had a maximum takeoff weight of 21,000 kg (47,000 lb).
7. Boeing CH-47D Chinook
One of the most popular helicopters in the world, the Chinook is a multi-mission, heavy lift transport unit with the primary mission to move troops, artillery, ammunition, fuel, water, barrier materials, supplies and equipment on the battlefield. Other purposes include medical evacuation, disaster relief, search and rescue, aircraft recovery, fire fighting, parachute drops, heavy construction and civil development.
The first fully equipped U.S. Army Chinook, designated the CH-47A, entered service in August 1962 with a gross weight of 14,969 kg or 33,000 lb.
With a tandem rotor design, the Chinook is touted as the world’s most reliable and efficient transporter helicopter, having a maximum takeoff weight of 22,680 kilograms (50,000 lb).
The Chinook has a triple hook system, which provides stability to large external loads or the capacity for multiple external loads. Large external loads such as 155mm howitzers can be transported at speeds up to 260km/h (161 mph) using the triple hook load configuration.
Measuring 30.1 meters or 98 feet 10 in in length and with a rotor diameter of 18.3 meters or 60 ft., the CH-47D had an empty weight of 10,185 kg (23,400 lb) and a cargo capacity of 12,700 kg (28,000 lb) or could carry 33 to 55 troops apart from the pilot, copilot and flight engineer. It is powered by two Lycoming T55-GA-712 turboshafts, each outputting 3,750 hp (2,796 kW).
6. Bell-Boeing V-22 Osprey
Not a helicopter per se, the Bell-Boeing V-22 Osprey takes off and lands like a rotorcraft, but travels like an airplane, its engine nacelles converting it into turboprop high-speed, high-altitude aircraft.
According to Bell-Boeing, the Osprey can carry 24 combat troops, or up to 9,072 kilograms (20,000 pounds) of internal cargo or 6,804 kilograms (15,000 pounds) of external cargo, at twice the speed of a 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 is the only vertical lift platform capable of rapid self- deployment to any theater of operation, worldwide.
Powered by two Rolls-Royce Allison T406/AE 1107C-Liberty turboshafts, each with a whopping output of 6,150 shp (4,590 kW), with a rotor diameter of 11.6 meters (38 feet) and a total length of 17.5 meters or 57 ft 4 in, the Bell-Boeing V-22 Osprey can lift up to 9,070 kg (20,000 lb) of internal cargo or up to 6,800 kg (15,000 lb) of external cargo and has a maximum takeoff weight of 27,400 kilograms (60,500 lb).
5. 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 13,600 kg or 30,000 lb and external of 14,500 kg or 32,000 lb, the Sikorsky CH-53E Super Stallion is the only helicopter that can lift the 155mm howitzer complete with crew and ammo. Moreover, it can lift aircraft as heavy as itself.
Powered by three General Electric T64-GE-416/416A turboshafts, each rated at 4,380 shp (3,270 kW), with a length of 30.2 meters of 99 ft 1/2 in and a rotor diameter of 24 meters or 79 ft, the Hurricane Maker (a nickname resulted from the downwash it generates) has a maximum takeoff weight of 33,300 kg or 73,500 lb.
It’s worth noting that the MH-53E Sea Dragon version, used for long range mine sweeping missions, has a bad reputation when it comes to reliability, being one of the most prone to accident helicopters.
4. Mil Mi-6
The chopper who set the trend in the ‘50s occupies a comfortable fourth place even after 50 years since its development, an impressive performance by the Russians at Mil.
With the NATO codename “Hook”, the Mi-6 is said to have entered production in 1960, 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 300 kph or 186 mph in level flight.
Powered by two Soloviev D-25V turboshafts with a combined output of 11,000 shp or 8,200 kW, with a staggering rotor diameter of 35 meters or 114 ft 10 in and a length of 33.18 meters of 108 ft 10 in, the Mi-6 had a maximum takeoff weight of 42,500 kg or 93,700 lb and an internal capacity of 12,000 kg (26,400 lb) of internal cargo. Its passenger capacity was of 90 passengers or 70 airborne troops.
3. Mil Mi-10
Developed in 1962 and based on the Mi-6, the Mil Mi-10 has a maximum takeoff weight of 43,700 kg or 96,340 lb. Though without a big difference in maximum takeoff weight, the “Harke” (NATO codename) has a payload on platform of up to 15,000 kilograms (33,070 lb) or an 8,000 kg (17,635 lb) 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 with neither internal clearance nor large loading doors for heavy cargoes. 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.
2. 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 have gone into production.
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 or 16,760 kW and has a maximum takeoff weight of 56,000 kilograms (123,500 lb). It can transport payloads of up to 20,000 kg (44,000 lb) for distances of up to 800 kilometers or 497 miles.
If you fail to assess the Mi-26’s humongous size and capacity, you should know that such a helicopter was used by the Americans to rescue one MH-47E Chinook.
The Mi-26 has a standard crew of four, including pilot, copilot, navigator, and flight engineer. The cockpit side windows are bulged to improve visibility. Three TV cameras are fitted to allow observation of loads. The cockpit is pressurized, though the cargo bay is not.
1. 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 taking place in 1968 and public debuting in 1971 at the Paris Air Show. Codenamed Homer, the Mi-12 used a side-by-side rotor scheme, each rotor being powered by two Soloviev D-25VF turboshafts, each outputting 4,125 kW or 5,500 shp. This means that Homer had a total output of 22,000 shp or 16,500 kW.
With a length of 37 meters or 121 ft 4 in and a rotor diameter of 35 m (114 ft 10 in), the Mi-12 has a maximum takeoff weight of 105,000 kg or 231,500 lb and holds the payload record with 44,205 kg (88,636 lb).