CH-46D Sea Knight

Naval aviation's first tandem-rotor
helicopter, the Piasecki HRP, appeared during World War II. Fabric
covered with a top speed of 104 M.P.H., its ungainly appearance earned
it the nickname “Flying Banana.” Nevertheless, it was on the shoulders
of this primitive helicopter that the Marine Corps first experimented
with the concept of heliborne assault. In 1962, the service ordered
another tandem-rotor design, the HRB (later designated CH-46) Sea
Knight, featuring a rear cargo-loading ramp, a top speed of 166 M.P.H.,
and the ability to carry 4,000 lb. of cargo or 22 combat-equipped
troops.

The first Sea Knights were delivered in June 1964, and as U.S.
operations intensified in South Vietnam, there was a concerted effort to
deploy them in-country to augment and ultimately replace the UH-34s in
Marine Medium Helicopter Squadrons (HMM). The first squadron of CH-46s
arrived in theater in March 1966, and during the first 35 days of
operations, HMM-164 flew almost 2,700 combat sorties in the Sea Knight’s
baptism of fire.

While the fuselages of squadron helicopters received holes from
enemy fire during these combat hops, the operating environment proved
equally worrisome. The dust and sand of South Vietnam, when sucked into
the helicopter’s engine compressor, caused the engine to lose power.
The particles also infiltrated the fuel systems and caused abrasions on
the rotor blades. Modifications to the type, which included the
installation of air filters and rotors with nickel-plated leading edges,
helped remedy the problems. Deadly structural failures for a time
grounded the aircraft, but over time and with the introduction of the
more capable CH-46D version of the Sea Knight, the helicopter
affectionately known as the “Phrog” became a mainstay of the Vietnam
War. Over the course of the first true helicopter war, 106 leatherneck
Sea Knights fell to enemy fire in missions ranging from supplying remote
base camps to battlefield insertion and extraction to medical
evacuation (MEDEVAC). The final flight for a Marine Corps CH-46 in
South Vietnam occurred on April 30, 1975, when a “Phrog” extracted the
last leathernecks of the Marine security detail from the rooftop of the
American embassy during the evacuation of Saigon.

The CH-46 continued to serve the Marine Corps for the ensuing four
decades with Marine Expeditionary Units (MEU) typically including Sea
Knights on board amphibious assault ships to transport leathernecks
ashore. The last version of the helicopter, the CH-46E, saw heavy
combat service in the Global War on Terror in the sands of Iraq and the
rugged terrain of Afghanistan. In the former theater of operations,
“Phrogs” were a vital cog in the evacuation of casualties. “These guys
flew in horrible conditions, facing everything from Iraqi aggressors to
bad weather, to get as close to an injured Marine as possible,” one
flight surgeon said of the abilities of the CH-46 pilots and aircrews.
“During the heavier fighting, they would fly low and slow to make their
way through dust storms and low visibility just to pick up a patient.”

While the Marine Corps, which retired its last CH-46Es in 2015, was
the primary user of the Sea Knight, those in Navy markings performed a
valuable function supporting deployments around the world. Equipping
Helicopter Combat Support Squadrons (HC), CH-46s operating in
detachments on board combat support ships carried everything from spare
parts to food to ordnance to combatants as part of vertical
replenishment (VERTREP) operations. Called “the 46 dance,” CH-46s spent
hours flying between ships with pallets of cargo suspended beneath
their fuselages. As one pilot remembered, the helicopter was always
ready, “whether it was a medevac (medical evacuation) or getting a Coke
to a sailor.” Some Sea Knights were designated HH-46s and operated as
search and rescue platforms. The Navy also employed a limited number of
RH-46s as minesweeping platforms. The last Navy CH-46s were retired
from service in 2004.

The museum's CH-46D (Bureau Number 151952) spent much of its
operational service in Helicopter Combat Support Squadron (HC) 6, It was
flight delivered to the museum in 2003, by the squadron's commanding
officer.

Specifications

Manufacturer: Vertol Division of the Boeing Company

Dimensions: Length: 44 ft., 10 in.; Rotor Diameter: 51 ft.; Height: 16 ft., 8 ½ in.

Weights: Empty: 13,065 lb.; Gross Weight: 23,000 lb.

Power Plant: Two 1,400 horsepower General electric T58-GE-10 shaft turbines

Performance: Maximum Speed: 166 M.P.H. at sea level; Service Ceiling: 14,000 ft.; Range: 230 miles

Crew: Two pilots, one crew chief and up to 22 assault troops