The military helicopter has been an indispensable tool of war ever since its arrival during the Second World War, and it is the rare military service that doesn’t have at least some rotary-wing assets to call upon in times of peace and war.
From the tiny piston-powered eggbeaters of the 1940s helicopters have increased in both size and capability. One of the largest and most powerful helicopters in service today is the Sikorsky CH-53K King Stallion, which has recently entered service with the United States Marine Corps (USMC).
A lineal descendant of the first heavy-lift rotary-wing aircraft in service with the United States Navy (USN) and the USMC, the King Stallion is the largest helicopter in US military service and one of the largest military cargo/utility rotary-wing aircraft flying today. The CH-53K can transport very heavy loads slung externally, and can also carry standard military cargo pallets and even some military vehicles internally, which provides the USMC with great flexibility when planning logistical airlift missions.
Several other nations have either planned to purchase the platform in the near future or are currently evaluating the King Stallion for possible procurement. Future roles for the aircraft beyond cargo/utility missions are a distinct possibility as the CH-53K is still in its developmental infancy.
The USMC embraced vertical-lift platforms with enthusiasm and quickly incorporated a variety of helicopters into their force structure. The Marines have been responsible for much innovation in the tactical employment of helicopters on active operations.
An early USMC need for heavy vertical-lift capability led to a formal requirement for a Heavy Helicopter, Experimental (HH(X)) program in 1962.
Manufacturer Sikorsky offered a twin-engine design known as the S-65, which was prototyped as the YCH-53A and first flown in 1964. In 1966 the first production models were delivered as the CH-53A Sea Stallion, which saw combat service in South-East Asia.
The CH-53A/D Sea Stallion spawned several variants for naval and air force use, with the Navy using the RH-53A/D for minesweeping, and the USAF employing the HH-53 B/C Super Jolly Green Giant for aircrew rescue in Vietnam.
The last twin-engine variant of the Sea Stallion was the USAF’s MH-53 H/J/M Pave Low, a specialised variant for special operations and long-range combat rescue, fitted with sophisticated avionics for all-weather operation, protective armour and defensive weaponry.
The Sea Stallion was an excellent design, but Sikorski privately started on an upgraded version with three engines and a larger rotor system. This foresight was to pay dividends for the company soon.
In 1967 the USMC issued a tender for a helicopter that could lift nearly double the payload of the CH-53D, so Sikorski offered the re-design concept that they had been tinkering with, which was known as the S-80. The Corps saw this as a quick, low-cost solution and funded a prototype which first flew as the YCH-53E in 1974.
This was ordered as the CH-53E Super Stallion in 1978, and service procurement began in 1981.
With the USN ordering small numbers for shipborne re-supply tasking, the number of Super Stallions ordered was 177 units. The USN also ordered a specialised variant for mine-sweeping work known as the RH-53E Sea Dragon.
The Super Stallion served valiantly over the decades in a number of conflicts and natural disasters, but the platform was showing its age by the 2000s. By this point the USMC were examining proposals for refurbishing the CH-53E fleet, but once again Sikorski was quickly on the front foot with an upgraded design of the airframe.
Instead of upgrading the existing fleet, the Marines selected this option.
Sikorski’s new heavy-lift helicopter concept was initially known as the CH-53X, and was offered to the USMC in April 2006. The Marines quickly ordered 156 aircraft as the CH-53K King Stallion, and deliveries were expected to be completed by 2021. This urgency was mandated by the need of the Corps to start retiring Super Stallions by 2009, as structural airframe life limits were expected to be reached on most of the CH-53E fleet by 2010-11.
The design was formalised over 2009-10, and four pre-production models were ordered for air and ground tests with the first of these being delivered in December 2012. October 2015 saw the first flight of a test airframe.
The first production aircraft was delivered to the USMC in May 2018, but some technical glitches saw combat-ready aircraft delivery delayed from the initial expected date of 2019 until 2020. Initial Operational Capability (IOC) for the platform was declared by the USMC in April 2022.
The King Stallion boasts some very impressive dimensions, as to be expected from one of the largest military helicopters flying these days.
The cargo hold is particularly cavernous, able to accommodate large amounts of freight, a nearly platoon-sized passenger component, or even small vehicles.
It is physically huge too, at 28 feet 4 inches (8.650 metres) tall, 73 feet 1 inch (22.29 metres) long, and 17 feet 6 inches (5.33 metres) wide.
The diameter of the main rotor is 79 feet (24 metres) and the overall length of the airframe is 99 feet (30 metres), though this can be exceeded when the re-fuelling probe is extended for use.
The CH-53K has four crew members, with two pilots and two loadmasters – however, future variants for specialised tasking may have larger crewing requirements. The King Stallion can transport over thirty combat-equipped passengers, or can accommodate 24 medical litters. The maximum payload is 35,000 pounds (15,870 kilograms), and this weight can also be carried as a single load under the airframe’s centre cargo hook. The Maximum Take-Off Weight (MTOW) of the King Stallion is 88,000 pounds (39,916 kilograms).
The King Stallion is powered by three General Electric GE38-1B (also known as the T408) turboshaft engines, each of which generates 7,500 ship horsepower. These power plants drive a massive eight-blade main rotor, and the tail rotor is tilted down to help with low-speed flight characteristics.
Incredibly, the tail rotor by itself generates the same amount of lift as the main rotor on a medium utility helicopter! The maximum speed of the CH-53K has not been disclosed, but the platform is known to have a high cruise speed of nearly 200 mph (310 km/h).
The King Stallion has internal tankage to carry 1,900 Imperial gallons (8,650 litres) of fuel, and the cabin can accommodate auxiliary tanks that can carry 2,000 imperial gallons (9,100 litres) of additional fuel for ferry missions. The total unrefuelled range of the CH-53K is 530 miles (850 kilometres), and the combat range is 130 miles (200 kilometres). The service ceiling of the King Stallion is 16,000 feet (4,900 metres).
Procurement, roles and possible variants
The King Stallion has approximately the same dimensions and ship-borne ‘footprint’ of its predecessor, but has capabilities far superior to the CH-53E including a higher top speed and payload capacity. Able to lift nearly twice as much cargo, the ability of the King Stallion to carry two standard military cargo pallets internally is much utilised, as loads don’t have to be broken down for further transhipment once delivered by military airlifters like the C-17 Globemaster.
Besides the USMC the only other operator of the King Stallion is the Israeli Air Force (IAF), which signed an order for twelve CH-53Ks in April 2021. These are being procured to replace an earlier CH-53 Sea Stallion variant in service in Israel, and the high speed and long range of the new aircraft have been stated as the main reasons for the order.
The USN may procure the platform into the future, for heavy vertical replenishment of ships at sea, or as a specialised mine-countermeasures version similar to the MH-53E Sea Dragon.
Japan and Germany have also shown interest in the King Stallion, as both nations have operated earlier models of the airframe in national service. Despite the proven capability of the twin-engine CH-53G in German army service, the government decided to procure the CH-47F Chinook instead. Japanese interest in the King Stallion continues, as the MH-53E Sea Dragon currently serves with the JMSDF.
The airframe is in the infancy of its developmental cycle, and as such the possibility of specialised variants of the King Stallion being manufactured in the future should not be arbitrarily dismissed as unlikely. The USAF and other national air arms may investigate the feasibility of a specialised long-range combat rescue/special operations version of the King Stallion, as earlier marques of the CH-53 range have shown themselves to be adept at performing aircrew rescue, and other high-risk missions.
No armament fitouts for the CH-53K have been disclosed, but like the Super Stallion the aircraft is capable of mounting machine guns at hatches each side behind the cockpit, with an additional weapon able to be employed from the rear load ramp (when opened). A specialised variant based on the Pave Low would mount far heavier weaponry, as well as protective armour and sophisticated avionics for all-weather operations.
Further orders from a number of nations may eventuate into the future, as the current international climate is bleak, with geo-political tensions worsening around the globe. In both wars and natural disasters rotary-wing aircraft are worth their weight in gold, and the CH-53K may be in an advantageous position for future orders around the world.
The United States has several modern aircraft that are excellent in both design and reputation, and the eventual replacement for these platforms is quite often an upgraded or re-designed version of the current variant in service. Examples of this are the CH-47 Chinook or the C-130 Hercules, both of which have long service records – and new models appearing regularly even better than those currently in the national inventory.
The CH-53K is the newest chapter in this story, with the King Stallion a direct descendant of the CH-53A Sea Stallion which was adopted for service in the 1960s.
The King Stallion is one of the finest and most capable heavy-lift helicopters in military service today, and the type is expected to serve for many decades. Fast, powerful and very capable, the CH-53K will be the backbone of USMC vertical lift capability into the future, and may be procured by other national services as well.
It stands as a prime example of replacing an excellent platform with an even more capable version, and of a weapons program that produced a remarkably smooth procurement process for the platform- – this is a rarity in itself.