Boeing Vertol CH-46 Sea Knight

https://en.wikipedia.org/wiki/Boeing...-46_Sea_Knight

The Boeing Vertol CH-46 Sea Knight is a medium-lift tandem-rotor transport
helicopter powered by twin turboshaft aircraft engines designed by Vertol and
manufactured by Boeing Vertol following Vertol's acquisition by Boeing.

Development of the Sea Knight, which was originally designated by the firm as
the Vertol Model 107, commenced during 1956. It was envisioned as a successor to
the first generation of rotorcraft, such as the H-21 "Flying Banana", that had
been powered by piston engines; in its place, the V-107 made use of the emergent
turboshaft engine. On 22 April 1958, the V-107 prototype performed its maiden
flight. During June 1958, the U.S. Army awarded a contract for the construction
of ten production-standard aircraft, designated as the YHC-1A, based on the
V-107; this initial order was later cut down to three YHC-1As though. During
1961, the U.S. Marine Corps, who had been studying its requirements for a
medium-lift, twin-turbine troop/cargo assault helicopter, selected Boeing
Vertol's model 107M as the basis from which to manufacture a suitable rotorcraft
to meet their needs. Known colloquially as the "Phrog" and formally as the "Sea
Knight", it was operated across all U.S. Marine Corps' operational environments
between its introduction during the Vietnam War and its frontline retirement
during 2014.

The Sea Knight was operated by the United States Marine Corps (USMC) to provide
all-weather, day-or-night assault transport of combat troops, supplies and
equipment until it was replaced by the MV-22 Osprey during the 2010s. Additional
tasks that the type was used for in USMC service included combat support, search
and rescue (SAR), support for forward refueling and rearming points, CASEVAC and
Tactical Recovery of Aircraft and Personnel (TRAP). The Sea Knight also
functioned as the United States Navy's standard medium-lift utility helicopter
prior to the type being phased out of service in favor of the MH-60S Knighthawk
during the early 2000s. Several overseas operators acquired the rotorcraft as
well. Canada operated the Sea Knight, designated as CH-113; the type was used
predominantly in the search and rescue (SAR) role until 2004. Other export
customers for the type included Japan, Sweden, and Saudi Arabia. The commercial
version of the rotorcraft is the BV 107-II, commonly referred to simply as the
"Vertol".


Role
Cargo helicopter

National origin
United States

Manufacturer
Vertol Aircraft Corp.
Boeing Vertol

First flight
22 April 1958 (V-107)

Introduction
1964

Retired
2004 (United States Navy)
2015 (USMC)

Status
In limited service

Primary users
United States Marine Corps (historical)
United States Navy (historical)
Japan Ground Self-Defense Force (historical)
United States State Department

Produced
1962–1971

Number built
H-46: 524

Developed into
Boeing CH-47 Chinook

Known colloquially as the "Phrog", the Sea Knight was used in all U.S. Marine
operational environments between its introduction during the Vietnam War and its
frontline retirement in 2014. The type's longevity and reputation for
reliability led to mantras such as "phrogs phorever" and "never trust a
helicopter under 30". CH-46s transported personnel, evacuated wounded, supplied
forward arming and refueling points (FARP), performed vertical replenishment,
search and rescue, recovered downed aircraft and crews and other tasks.

During the Vietnam War, the CH-46 was one of the prime US troop transport
helicopters in the theatre, slotting between the smaller Bell UH-1 Iroquois and
larger Sikorsky CH-53 Sea Stallion. During the 1972 Easter Offensive, Sea
Knights saw heavy use to convey US and South Vietnamese ground forces to and
around the front lines. CH-46 operations were plagued by major technical
problems; the engines, being prone to foreign object damage (FOD) from debris
being ingested when hovering close to the ground and subsequently suffering a
compressor stall, had a lifespan as low as 85 flight hours; on 21 July 1966, all
CH-46s were grounded until more efficient filters had been fitted. By the end of
US military operations in Vietnam, over a hundred Sea Knights had been lost to
enemy fire.

CH-46E Sea Knights were also used by the U.S. Marine Corps during the 2003
invasion of Iraq. In one incident on 1 April 2003, Marine CH-46Es and CH-53Es
carried U.S. Army Rangers and Special Operations troops on an extraction mission
for captured Army Private Jessica Lynch from an Iraqi hospital. During the
subsequent occupation of Iraq and counter-insurgency operations, the CH-46E was
heavily used in the CASEVAC role, being required to maintain 24/7 availability
regardless of conditions. According to authors Williamson Murray and Robert H
Scales, the Sea Knight displayed serious reliability and maintenance problems
during its deployment to Iraq, as well as "limited lift capabilities". Following
the loss of numerous US helicopters in the Iraqi theatre, the Marines opted to
equip their CH-46s with more advanced anti-missile countermeasures.

The U.S. Navy retired the type on 24 September 2004, replacing it with the
MH-60S Seahawk; the Marine Corps maintained its fleet as the MV-22 Osprey was
fielded. In March 2006 Marine Medium Helicopter Squadron 263 (HMM-263) was
deactivated and redesignated VMM-263 to serve as the first MV-22 squadron. The
replacement process continued through the other medium helicopter squadrons into
2014. On 5 October 2014, the Sea Knight performed its final service flight with
the U.S. Marine Corps at Marine Corps Air Station Miramar. HMM-364 was the last
squadron to use it outside the United States, landing it aboard the USS America
(LHA-6) on her maiden transit. On 9 April 2015, the CH-46 was retired by the
Marine Medium Helicopter Training Squadron 164, the last Marine Corps squadron
to transition to the MV-22. The USMC retired the CH-46 on 1 August 2015 in a
ceremony at the Udvar-Hazy Center near Washington DC. The HH-46E variant
continued to operate in a Search and Rescue capacity at Marine Corps Air Station
Cherry Point. The last flight of a Marine Corps H-46 took place on 25 September
2015 at MCAS Cherry Point and ended the 57-year Cherry Point Search and Rescue
program.

Specifications (CH-46E)

General characteristics
Crew: five: two pilots, one crew chief, one aerial gunner/observer, one tail
gunner
Capacity: ** 24 troops or 15 stretchers and two attendants or
5,000 lb (2,270 kg)

Length: 44 ft 10 in fuselage (13.66 m
Fuselage width: 7 ft 3 in (2.2 m))
Rotor diameter: 50 ft (15.24 m)
Height: 16 ft 9 in (5.09 m)
Disc area: 3,927 ft² (364.8 m²)
Empty weight: 11,585 lb (5,255 kg)
Loaded weight: 17,396 lb (7,891 kg)
Max. takeoff weight: 24,300 lb (11,000 kg)
Powerplant: 2 × General Electric T58-GE-16 turboshafts, 1,870 shp (1,400 kW)
each

Performance
Maximum speed: 166 mph (144 knots, 267 km/h)
Range: 633 mi (550 nmi, 1,020 km)
Ferry range: 690 mi (600 nmi, 1,110 km)
Service ceiling: 17,000 ft (5,180 m)
Rate of climb: 1,715 ft/min (8.71 m/s)
Disc loading: 4.43 lb/ft² (21.6 kg/m²)
Power/mass: 0.215 hp/lb (354 W/kg)

Armament

Guns: Two door-mounted GAU-15/A .50 BMG (12.7×99 mm) machine guns (optional),
one ramp-mounted M240D 7.62×51 mm machine gun (optional)




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