The Evolution of the Amphibious Task Force and the Coming of the CH-53K

By Robbin Laird

The venerable CH-53 has been a staple for Marines in providing heavy lift since the Vietnam War.

The origins of the heavy lift helo is described by Wikipedia as follows:

In 1960, the United States Marine Corps began to seek a replacement for their HR2S piston-powered helicopters. On 27 January 1961, the Marine Corps began working with the other three U.S. armed services on the “Tri-Service VTOL transport”, which would eventually emerge as the Vought-Hiller-Ryan XC-142A tiltwing. 

The design became more elaborate and the program stretched out, causing the Marines to drop out when they decided they would not receive a working machine in a satisfactory timeframe. In the end, the XC-142A, although a very innovative and capable machine, never entered production. 

In March 1962, the United States Navy’s Bureau of Naval Weapons, acting on behalf of the Marines, issued a request for a “Heavy Helicopter Experimental / HH(X)”. The specifications dictated a load capability of 8,000 pounds (3,600 kg) with an operational radius of 100 nautical miles (190 km; 120 mi) at a speed of 150 knots (280 km/h; 170 mph). The HH(X) was to be used in the assault transport, aircraft recovery, personnel transport, and medical evacuation roles. In the assault transport role, it was to be mostly used to haul heavy equipment instead of troops. 

Sikorsky YCH-53A. Credit: Sikorsky
Sikorsky YCH-53A. Credit: Sikorsky

In response, Boeing Vertol offered a modified version of the CH-47 Chinook; Kaman Aircraft offered a development of the British Fairey Rotodyne compound helicopter; and Sikorsky offered what amounted to a scaled-up version of the S-61R, with twin General Electric T64 turboshafts and the dynamic system of the S-64, to be designated the “S-65”. 

Kaman’s proposal quickly died when the British government dropped its backing of the Rotodyne program. Competition between Boeing Vertol and Sikorsky was intense, with the Chinook having an advantage because it was being acquired by the United States Army. Sikorsky threw everything into the contest and was awarded the contract in July 1962. 

The YCH-53A prototype in 1964 

The Marines originally wanted to buy four prototypes but ran into funding problems. Sikorsky, determined to keep the deal, cut their estimate for development costs and said that the program could be done with two prototypes. The military bought off on the proposal, and in September 1962 Sikorsky was awarded a contract for a little under US$10 million for two “YCH-53A” prototypes, as well as a mockup and a ground-test airframe. 

The development program did not go entirely smoothly, due to a shortage of engineering resources plus various failures of subcontractors and the government, but these problems were gradually overcome. There was also the problem that U.S. Secretary of Defense Robert S. McNamara was pushing to maintain “commonality” between the armed services by using the Chinook, but the Marines managed to convince McNamara’s staff that the Chinook could not meet their requirements without numerous expensive changes. 

All these obstacles overcome, the first YCH-53A performed its initial flight at the Sikorsky plant in Stratford, Connecticut, on 14 October 1964, about four months behind schedule. The Marines had already placed an initial production contract for 16 helicopters in September. Flight trials went more smoothly than expected, helping make up for the lost time in development. It received the military designation and name “CH-53A Sea Stallion”. Delivery of production CH-53s began in 1966. 

The CH-53A arrived in Vietnam in January 1967 and proved useful, eventually recovering even more downed aircraft than the CH-54. A total of 141 CH-53As were built, including the two prototypes. The U.S. Navy acquired 15 CH-53As from the USMC in 1971 for airborne mine countermeasures (AMCM) activities. The helicopters had more powerful T64-GE-413 turboshafts installed and received the designation “RH-53A”.

There have been changes over the years as the CH-53 migrated from an A to an E model.

But it has been a voyage of a Type/Series/Model not unlike other programs, changes have been made, upgrades have been built in, but the basic helicopter has been recognizable throughout its evolution.

A comprehensive look at the evolution of the helicopter from the A through to the E has been provided in the Sikorsky archives and can be found here:

The original helicopter was later modified to the CH‑53D, which had more powerful engines and added engine air particle separators to prevent ingestion of dust.

Ch-53E operating in Afghanistan. Credit: USMC
Ch-53E operating in Afghanistan. Credit: USMC

The growth version of the CH‑53D added a third engine and a seventh main rotor blade, drastically increasing maximum gross weight by 75%.

It became the largest and most powerful helicopter outside of Russia.

Although a CH-53, the CH-53K is not easily understood as an evolution of earlier models.

The predicate for the CH-53 series really is founded in the context of 1960s technologies and concepts of operations.

The predicate for the CH-53K is 21st century military aviation, approaches, materials and technologies and is entering the force when a very different concept of operations is being shaped than the one forged in the 1960s and which evolved forward from the Vietnam War.

And as a 21st century platform which is designed to be embedded into a transformed USMC insertion force, enabled by Ospreys, F-35Bs, and digital interoperability among other new technologies, the K is both enabled by and enables the shift to distributed operations.

The K has come on line more slowly than intended, in part because putting together the pieces of a new 21st century capability into an integrated platform is not easy. And because the new platform is quite different from its predecessor, in terms of design, construction, testing, and capabilities, it is not as easy to describe as if it was a completely new type of aircraft.

Nonetheless, it is a 21st century aircraft for a 21st century USMC and its approach to operations.

For the Marines, this shift started with the Osprey and lessons learned there are being applied to the K program as well.

And given the key role of VMX-22 (Now VMX-1) in the Osprey, F-35B and K programs, the squadron will shape lessons learned helpful across 21st century innovation for the air element for the USMC.

Clearly, the K is part of this evolving transition which the following graphic highlights.


A version of this article was published on March 3, 2016.