The Sea Knight is a medium lift assault helicopter, primarily used to move cargo and troops.
Sea Knight Background
Readily identified among current
Navy and Marine Corps helicopters are the H-46 series Sea Knights, with
their tandem rotor configuration setting them apart from the single rotor
design of other Navy/Marine helos. Tandem rotors have been a feature of
all production helos built by Boeing/Vertol, and its original predecessor
company, Piasecki.
In 1958, Vertol completed a company sponsored prototype of a new helicopter design, powered by two Lycoming T-53 turbine engines for potential military or civilian use. The 107 first flew in April, exhibiting most of the basic configuration characteristics to be found in all of its 107-series successors. The Army ordered three YHC-1As which were developed as GE-T-58-powered military evaluation vehicles under a Bureau of Aeronautics contract. First flying in August 1959, the YHC-1As were followed by an improved commercial/export model, the 107-11.
During 1960, the Marines evolved a requirement for a twin-turbine troop/cargo assault helicopter to replace the piston engine types then in use. Following a design competition, Boeing/Vertol was selected to build its model 107M as the HRB-1, early in 1961. It retained the general configuration of its predecessors, including the aft sponsons carrying the fixed main gear, a fixed nose gear and built-in emergency flotation provisions so it could land and take off from the water in light seas. Special features included power-operated blade folding, integral cargo handling provisions, a rear loading ramp that could be left open in flight, personnel recovery and rescue equipment, and provisions for hoisting 10,000 pounds externally. These and other features marked a significant step forward in helicopter capability in the time period.
First
flight in August 1962 was followed by a change in designation to CH-46A,
development flight testing, (including the first NPE in January 1963),
and BIS trials beginning in March 1964. Fleet introduction of CH-46As with
the Marines and UH-46As with the Navy took place in November 1964. The
latter were modified for use in the vertical replenishment role.
Production continued in subsequent years, along with modifications to improve some of the H-46's characteristics. With service in SEAsia came installation of guns and armor. Increased power requirements were met by installation of higher powered T-58-GE-10s in the CH/UH-46D models, which also featured new cambered (droop snoot) rotor blades. The final CH-46E, with further increased power, was preceded by the last production version, the CH-46F, before production was completed with delivery of the 524th H-46 in February 1971.
The early A models now serve as search and rescue HH-46As. CH-46s equip Marine Reserve squadrons, and conversion of earlier aircraft to the new CH-46E version was completed with fiberglass blades slated added to its other improvements. The current H-46 Sea Knight Block Upgrade provides for installation of increased fuel capacity stub wings and an emergency helicopter flotation system. The H-46 Dynamic Component Upgrade provides for safety, engineering and electronic improvements.
Sea Knight Mission
The CH-46 Sea Knight was first procured
in 1964 to meet the medium-lift requirements of the Marine Corps in all
combat and peacetime environments since that time. The Sea Knight fleet
is currently being maintained until a suitable replacement is approved.
The CH-46D Sea Knight helicopter is used by the Navy for shipboard delivery of cargo and personne. The CH-46E is used by the Marine Corps to provide all-weather, day-or-night assault transport of combat troops, supplies and equipment. Troop assault is the primary function and the movement of supplies and equipment is secondary. Additional tasks may be assigned, such as combat support, search and rescue, support for forward refueling and rearming points, aeromedic evacuation of casualties from the field and recovery of aircraft and personnel.
Information and photos provided by the United States Navy
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