The Boeing CH-46 Sea Knight (aka Model 107) is a product of the Vertol Aircraft Corporation. Vertol has been around in one form or another since 1940, when it was known as the Piasecki Helicopter Corporation. After being bought out by Laurance Rockefeller A. Felix Du Pont and eventually ousting Mr. Piasecki, the company changed names to Vertol. The word “vertol” is another term for the modern day “VTOL” or vertical takeoff and landing. Boeing bought the company in 1960 and rather unimaginatively named it Boeing Vertol. Since 1987 it is simply the Boeing Helicopter Division.
The Sea Knight was produced in response to a need for the US Marine Corps (USMC) to have an all-weather, round-the-clock assault transport.
The answer came in the form of the CH-64. A tandem rotor helicopter. A design that Piasecki pioneered with its “flying bananas” HRP-1. A heritage that shines through in the Sea Knight. Like most tandem rotor helicopters the Sea Knight has twin engines. Both are at the aft rotor, with a drivetrain running to the other. This design allows either of the GE T58 turboshaft units to power both rotors in case of engine failure. As the CH-46 was designed for marine use, its three-blade rotors can be folded while on a carrier. The clever design features don’t end there. The fixed tricycle type landing gear are configured in such a way that the Sea Knight stands nose up, which makes cargo loading easier. The rear wheels are also embedded in sponsons that double as fuel tanks.
The Sea Knight’s abilities are rounded out by a removable loading ramp that can also be left open during flight, allowing flexible multi-mission applications. There is also a belly sling rated at 10 000 lb (4 500 kg), but the aircraft’s engines are not powerful enough for that class of load.
The Sea Knight can operate with a crew of only three, although some variants carry a crew of five. The helicopter is also far from toothless, thanks to twin side-mounted 12.7mm Browning machine guns and additional armor, thanks largely to operations in southeast Asia.
More than 600 Sea Knights were delivered by 1990. It served as the U.S. Navy’s standard medium-lift utility helicopter until it was supplanted by the MH-60S Knighthawk in the early 2000s. The Sea Knight flew its final service flight for the USMC in October of 2014. Today it’s place has been taken by the V-22 Osprey.