The Boeing-Vertol CH-46 Sea Knight was a troop-transport, twin-rotor helicopter in service with the US Navy and US Marine Corps between 1964 and 2023. It was widely used during the Vietnam War both as a troop transport and utility chopper. Due to its mechanical and technical reliability and its impressive performance, the CH-46 had a very long career in the United States, where it would also be employed as a search and rescue chopper by the US Coast Guard in the HH-46 version. It saw combat action world-wide, from Southeast Asia to Iraq and Afghanistan. However, it had one weakness: it had thin armor and it was vulnerable to small arm fire, such as machine guns. Nevertheless, it was an effective assault helicopter used by the US Marine Corps.
The prototype of the Boeing Vertol CH-46 Sea Knight first took to the air on April 22, 1958. The first production helicopters rolled out of the factory in October 1962 and they were accepted into service with the US Navy and Marine Corps two years later, on May 28, 1964. When the Sea Knight was introduced, it provided a new standard of performance to the United States as it was a versatile helicopter especially designed for combat troop transport and logistic support. To the US Navy, this meant vertical replenishment, using this helicopter to haul cargoes to ships at sea. The US Marine Corps, on the other hand, used it to carry combat troops directly into battle. Many veterans who served in Vietnam are alive today because the CH-46 snatched them out of danger and flew them to safety, away from the battlefield. The Marines called it the ''flying bullfrog''.
Technical Characteristics
The Boeing CH-46 Sea Knight was a twin-turbine, medium-lift helicopter, with a tandem-rotor configuration. The fuselage was all-metal, with three, small, round windows and a side door on each side and a large rear ramp door to facilitate quick troop access and exit and cargo loading. Up to twenty-five fully-equipped combat troops could be carried in the fuselage. The cockpit was large enough to seat two pilots and a load-master as improved avionics were fitted inside. The CH-46E version was powered by two General Electric T58-GE-16 turboshaft engines, each one delivering 1,870 horsepower. The three-bladed rotors rotated in opposite direction to counterbalance each other and avoid an out-of-control spiraling spin. The blades were made of glassfiber. The landing gear was non-retractable and it was strengthened to withstand the high rates of vertical sink. The CH-46A, CH-46D, and CH-46E were the assault and cargo transport versions used by the US Marine Corps, while the UH-46A-B and D were the US Navy utility variant.
Specifications (CH-46E)
Type: assault/troop transport helicopter
Rotor Diameter: 15.24 m (50 feet)
Rotor Disc Area: 182.41 m2 (1,963 square feet)
Fuselage Length: 13.67 m (44 feet, 10 inches)
Power Plant: two 1,870-HP, General Electric T58-GE-16 turboshaft engines
Maximum Speed: 256 km/h (159 mph)
Range: 996 km (618 miles)
Capacity: 25 troops
Armament: two 12,7-mm (.50-cal) M2 Browning machine guns.
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| Above, the Navy's utility version of the Sea Knight. |
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| Two CH-46s of HMM-161 transporting marines of the 1st Marine Division during a Search and Rescue operation in Da Nang, South Vietnam. |
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| A HH-46 variant for search and rescue operations. |
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| Above, a CH-46D version of the US Marine in South Vietnam in 1969. |