What designation was given to the Navy's first helicopter accepted on 16 October 1943?

The designation given to the Navy's first helicopter accepted on 16 October 1943 was YR-4B. This helicopter was based on the Sikorsky R-4 and marked a significant milestone in naval aviation history as it represented the Navy's initial foray into rotary-wing aircraft. The YR-4B played a crucial role in the development of helicopter operations within the Navy, serving during World War II primarily for transport and search and rescue missions.

Other designations mentioned, such as the AH-1 Cobra, CH-53 Sea Stallion, and UH-1 Iroquois, refer to helicopters that were developed in later years and serve different roles in the Navy and Marine Corps, showcasing their evolution over time. The AH-1 Cobra is an attack helicopter introduced in the 1960s, while the CH-53 Sea Stallion is a heavy-lift transport helicopter that first entered service in the 1960s as well. The UH-1 Iroquois, also known as the "Huey," became iconic during the Vietnam War but was not introduced until after the YR-4B.