Cold War

The CH-37 Mojave is Bulbus, Ugly & Brilliant

The CH-37 Mojave was developed by Sikorsky Aircraft Corporation in the early 1950s, this aircraft set the stage for future advancements in helicopter design and capabilities. The Mojave’s design, development, operational use, and legacy illustrate its significant impact on both military and civilian aviation sectors.


Design and Development

The design and development of the Sikorsky CH-37 Mojave marked a pivotal moment in the advancement of helicopter technology. Sikorsky Aircraft Corporation took on the challenge of creating a heavy-lift helicopter that would meet the demanding requirements of the United States Marine Corps.

This endeavour required innovative thinking and engineering excellence to push the boundaries of what was possible with rotary-wing aircraft at the time.

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The primary objective for the Sikorsky team centred on achieving unparalleled payload capacity and operational range. To accomplish this, the designers opted for a piston-engine configuration, diverging from the more common turbine engine approach prevalent among helicopters during that period.

This decision resulted in the Mojave being powered by two Pratt & Whitney R-2800 Double Wasp engines, which were known for their reliability and high power output. These radial engines were key to providing the CH-37 with its remarkable lifting capabilities.

The Pratty & Whitney R-2800.
The Pratty & Whitney R-2800 was used in large numbers in aircraft such as the P-47 Thunderbolt, the F4U Corsair and the F6F Hellcat. The CH-37 used two of these beasts.

Sikorsky engineers designed the Mojave with a broad and robust fuselage to accommodate a wide variety of cargo, including vehicles, artillery pieces, and up to 26 troops. This versatility in cargo handling was further enhanced by the introduction of clamshell doors at the aircraft’s rear, a feature that significantly eased the process of loading and unloading cargo. The inclusion of a retractable undercarriage also contributed to the Mojave’s operational flexibility, allowing for smoother landings and take-offs even when carrying heavy loads.

Throughout the development process, Sikorsky conducted rigorous testing to refine the Mojave’s design. This phase included numerous flight tests to evaluate the helicopter’s performance, handling characteristics and reliability. The insights gained from these tests allowed the engineering team to make iterative improvements, enhancing the Mojave’s operational capabilities and ensuring it met the stringent standards required by the military.

Rotor System

The Sikorsky CH-37 Mojave’s rotor system stands as a remarkable feat of engineering, showcasing the advanced design and technological capabilities of its era. At the heart of the Mojave’s operational prowess lies its distinctive rotor configuration, which consists of a large main rotor and a smaller tail rotor. This setup was critical in providing the lift and control necessary for the helicopter’s heavy-lift missions.

The main rotor of the CH-37, characterised by its considerable diameter, was pivotal in generating the lift required to carry substantial payloads.

The combination of engine power and rotor design meant that the CH-37 could lift huge amounts of weight.
The combination of engine power and rotor design meant that the CH-37 could lift huge amounts of weight.

Engineers meticulously designed the rotor blades to ensure optimal aerodynamic efficiency, allowing the helicopter to hoist and transport loads that were unprecedented at the time. The blades’ construction involved cutting-edge materials and fabrication techniques of the day, ensuring they could withstand the stresses encountered during varied and demanding operations.

In complement to the main rotor, the tail rotor played an essential role in stabilising the helicopter and providing directional control. Given the Mojave’s considerable size and power, managing torque and ensuring stability during flight were paramount. The tail rotor’s design and placement were the results of extensive testing and refinement, aiming to maximise control and minimise pilot workload, especially when manoeuvring with heavy loads.

The Mojave was a do it all helicopter and could even lift the CH-21.
The Mojave was a do-it-all helicopter and could even lift the CH-21.

The synergy between the main and tail rotors was a critical aspect of the CH-37’s design. The interaction between these two rotor systems enabled the Mojave to achieve a level of agility and precision that was remarkable for a helicopter of its size and class. Pilots could rely on the Mojave for not just raw lifting power but also for the finesse required in placing loads with accuracy.

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Moreover, the rotor system of the CH-37 incorporated several innovative features aimed at enhancing performance and reliability. Among these was the introduction of a hydraulic control system, which significantly eased the effort required to manipulate the rotors, thereby reducing pilot fatigue during extended operations. This system was a testament to Sikorsky’s commitment to not only advancing helicopter capabilities but also to improving the operational experience for pilots.

They Mojave's ugly looks meant that it could carry a large internal payload too.
The Mojave’s ugly looks meant that it could carry a large internal payload too.

Operational Use

The CH-37’s entry into operational service with the United States Marine Corps in the late 1950s represented a significant leap forward in military logistics and mobility. The Mojave’s unique capabilities allowed it to undertake a variety of missions that were previously beyond the reach of other aircraft, making it an indispensable tool in the arsenal of the United States military.

Troop transport emerged as one of the primary roles of the CH-37, leveraging its spacious cabin to move soldiers swiftly and efficiently across the battlefield. This ability to rapidly deploy forces gave the United States Marine Corps a strategic advantage, enabling rapid response to evolving situations and the execution of complex manoeuvres with ease.

Beyond moving personnel, the Mojave excelled in the transportation of heavy equipment, including artillery pieces, light armoured vehicles, and supplies. Its robust lifting capacity and spacious cargo hold made it an ideal choice for logistical support, ensuring that front-line units had the necessary resources to maintain their operational effectiveness. The helicopter’s rear clamshell doors facilitated quick loading and unloading, significantly reducing turnaround times and enhancing the overall efficiency of military operations.

The CH-37 was THE heavy lift helicopter.
The CH-37 was THE heavy lift helicopter.

One of the Mojave’s most critical and high-profile roles involved the recovery of downed aircraft. Its powerful engines and sturdy design allowed it to lift and transport damaged helicopters and fixed-wing aircraft, often from difficult and inaccessible locations. This capability not only saved valuable equipment but also served as a morale booster for pilots, knowing that the Mojave could retrieve them and their aircraft if necessary.

The CH-37 also found a unique place in the history of space exploration. NASA enlisted the Mojave’s services for the recovery of space capsules, a task that required precision, reliability, and a gentle touch. The helicopter’s ability to retrieve capsules from the ocean and transport them safely back to land demonstrated its versatility and contributed to the success of early space missions. This role underscored the Mojave’s contribution to scientific progress and exploration, extending its impact beyond military achievements.

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The Sikorsky CH-37 Mojave, a heavy-lift helicopter developed primarily for the United States Marine Corps, came in several variants, each designed to meet specific operational requirements. These variants illustrate the helicopter’s versatility and the attempts by Sikorsky and the military to adapt the Mojave to different roles and technological advancements.

The initial production model of the Mojave was the CH-37A. This variant set the standard for what a heavy-lift helicopter could achieve, featuring the distinctive twin radial engines and the large, spacious fuselage capable of carrying substantial cargo or troops. The CH-37A demonstrated the Mojave’s potential in logistical support and troop transport, embodying the core capabilities that made the helicopter a valuable asset to the military.

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Following the CH-37A, Sikorsky introduced the CH-37B, which incorporated several improvements over the initial model. The CH-37B featured enhanced engines for better performance, especially in lift capacity and range. This variant also saw the introduction of updated avionics and control systems, improving overall flight characteristics and making the helicopter easier to pilot, especially during complex operations like precision cargo placement or recovery missions.

The HR2S-1W early warning variant.
The HR2S-1W early warning variant.

Another significant variant was the YH-37C, a proposed but ultimately not produced version intended for the United States Air Force. The YH-37C was to be a more refined model, equipped with turbine engines instead of the piston engines used in earlier versions. The transition to turbine power was expected to provide superior performance, including higher speeds and greater efficiency. However, the project did not proceed to full-scale production, largely because the Air Force’s requirements evolved, and newer helicopter designs became available.

In addition to these military variants, Sikorsky explored civilian adaptations of the Mojave. These versions aimed to leverage the helicopter’s heavy-lift capabilities for commercial use, such as construction, logging, and other industries requiring the transportation of heavy or oversized loads. While the civilian versions demonstrated the Mojave’s potential in commercial sectors, the widespread adoption was limited, partly due to the operating costs and the emergence of more modern, turbine-powered helicopters that offered better performance and efficiency.

The S-60

The Sikorsky CH-37 Mojave’s contributions to the evolution of helicopter design and capabilities played a pivotal role in the development of the Sikorsky S-60, a pioneering heavy-lift helicopter that followed in the Mojave’s footsteps. The CH-37 Mojave, with its robust design and operational success, laid the groundwork for Sikorsky engineers to innovate and push the boundaries of helicopter technology further, leading directly to the conception and creation of the S-60.

The experience gained from the CH-37 Mojave’s design, particularly its piston-powered engines and heavy-lift capabilities, provided Sikorsky with invaluable insights into the demands of heavy-lift aviation. Engineers learned the importance of power, reliability, and versatility in helicopter operations, especially in military contexts. These lessons became integral to the design philosophy behind the S-60, which sought to embody and enhance these characteristics.

The S-60 was eventually developed into the infamous Sky Crane.
The S-60 was developed into the infamous Sky Crane.

One of the critical ways in which the CH-37 influenced the S-60 was through its demonstration of the feasibility and effectiveness of large, piston-engine helicopters in performing a variety of missions. This realization encouraged Sikorsky engineers to explore more ambitious designs, leading to the adoption of a more powerful and innovative approach in the S-60. The Mojave’s success underscored the potential for heavy-lift helicopters, setting a precedent for the development of more advanced models.

Furthermore, the operational experiences of the CH-37 highlighted the need for improvements in payload capacity, flight performance, and operational efficiency. These operational insights directly informed the development of the S-60, as engineers sought to create a helicopter that could surpass the Mojave’s capabilities. The S-60 was designed to be a flying crane, with an open lattice structure for increased lift capacity and flexibility in carrying various loads, directly addressing the operational limitations observed in the CH-37.

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The transition from the CH-37 to the S-60 also reflected a shift in engineering focus towards more specialized heavy-lift applications. While the Mojave served as a multi-role heavy-lift helicopter, the S-60 was envisioned as a more focused tool, specifically designed for the lifting and precise placement of heavy loads. This specialisation was a direct consequence of understanding the diverse needs of heavy-lift operations, a comprehension deepened by the Mojave’s service.