CH-46 Sea Knight

Boeing Vertol CH-46 Sea Knight

The Boeing Vertol CH-46 Sea Knight is a medium-lift tandem rotor transport helicopter. It is used by the United States Marine Corps (USMC) to provide all-weather, day-or-night assault transport of combat troops, supplies and equipment. Additional tasks include 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 was also the U.S. Navy's standard medium-lift utility helicopter until it was phased out in favor of the MH-60S Knighthawk in the early 2000s. Canada also operated the Sea Knight, designated as CH-113, and operated them in the SAR role until 2004. Other export customers include Japan, Sweden, and Saudi Arabia. The commercial version is the BV 107-II, commonly referred to simply as the "Vertol".


In 1960, Boeing bought Vertol, a helicopter manufacturer in Philadelphia, Pa. The company had three tandem-rotor helicopters under production: the Chinook for the Army, the Sea Knight for the Navy and the Marines, and the commercial 107-II for the airlines.
The twin-turbine tandem-rotor CH-46A Sea Knight won a design competition for a medium assault transport helicopter for the Marine Corps in 1961 and made its first flight in August 1962.The first U.S. Marine Corps Sea Knight was delivered in 1964 and began military service during the Vietnam War a year later, carrying troops and cargo to and from Navy ships in the China Sea.By 1968, the Sea Knight had flown 75,000 hours on 180,000 missions, including 8,700 missions rescuing wounded Marines, and had carried 500,000 troops.Between 1964 and 1990, Boeing Vertol delivered over 600 Sea Knights. The passenger version of the Sea Knight, the Model 107-II, entered service with the New York Airways in July 1962. During the 1980s and 1990s, Boeing developed modification kits and upgrades to modernize the Sea Knights.

Specifications

First flight:	August 1962
Model number:	Vertol 107
Classification:	Military helicopter
Rotor diameter:	50 feet
Fuselage length:	44 feet 7 inches
Maximum gross weight:	23,000 pounds (CH-46D), 24,300 pounds (CH-46E)
Top speed:	165 mph
Cruising speed:	155 mph
Range:	265 miles
Ceiling:	12,800 feet (with normal load)
Power:	Two 1,250-horsepower T58-GE-8B engines
Accommodation:	3 crew, 17 troops or 15 litters and 2 attendants

Variants

American versions

Model 107 

Company model number for basic prototype, one built.

Model 107-II 

Commercial airline helicopter. All subsequent commercial aircraft were produced as BV 107-II-2, two built as Boeing Vertol prototypes, five sold to New York Airways, ten supplied to Kawasaki as sub-assemblies or as parts.

Model 107M 

Company model number for military transport of BV-107/II-2 for the U.S. Marine Corps.

YHC-1A 

Vertol Model 107 for test and evaluation by the United States Army. Adopted by the U.S. Marine Corps as the HRB-1. Later redesignated YCH-46C, three built.

HRB-1 

Original designation before being renamed as CH-46A before delivery under the 1962 United States Tri-Service aircraft designation system.

CH-46A 

Medium-lift assault and cargo transport and SAR helicopter for the USMC, fitted with two 1,250 shp (935 kW) General Electric T58-GE-8 turboshaft engines. Previously designated HRB-1. 160 built for USMC, one static airframe.

UH-46A 

Medium-lift utility transport helicopter for the United States Navy. Similar to the CH-46A. 14 built.

HH-46A 

Approximately 50 CH-46As were converted into SAR helicopters for the United States Navy base rescue role.

RH-46A 

Planned conversion of CH-46As into minesweeping helicopters for the US Navy, none converted. Nine SH-3As were converted to the RH-3A configuration instead.

UH-46B 

Development of the CH-46A to specification HX/H2 for the United States Air Force; 12 ordered in 1962, cancelled and Sikorsky S-61R / CH-3C ordered instead.

YCH-46C 

YHC-1A redesignated in 1962. United States Army retained two, NASA used one for vertical autonomous landing trials (VALT).

CH-46D 

Medium-lift assault and cargo transport helicopter for the USMC, fitted with two 1,400 shp (1,044 kW) General Electric T58-GE-10 turboshaft engines. 266 built.

HH-46D 

Surviving HH-46A were upgraded and a small number of UH-46Ds were converted into SAR helicopters. SAR upgrades included the addition of an external rescue hoist near the front crew door and an 18-inch X 18-inch Doppler RADAR system located behind the nose landing gear, which provided for automatic, day/night, over-water hovering capability for at sea rescue. Additionally a "Loud Hailer" was installed opposite the crew entrance door for communicating with downed aviators on the ground or in the water.

UH-46D 

Medium-lift utility transport helicopter for the US Navy combat supply role. Similar to the CH-46D. Ten built and one conversion from CH-46D.

CH-46E 

Approximately 275 -A, -D, and -F airframes were updated to CH-46E standards with improved avionics, hydraulics, drive train and upgraded T58-GE-16 and T58-GE-16/A engines.

HH-46E 

Three CH-46Es were converted into SAR helicopters for Marine Transport Squadron One (VMR-1) at MCAS Cherry Point.

CH-46F 

Improved version of CH-46D, electrical distribution, com/nav update BUNO 154845-157726. Last production model in the United States. 174 built, later reverted to CH-46E.

VH-46F 

Unofficial designation of standard CH-46F used by HMX-1 as VIP support transport helicopter.

CH-46X 

Replacement helicopter based on the Boeing Model 360, this Advance Technology Demonstrator from the 1980s never entered production. The aircraft relied heavily on composites for its construction and had a beefier drive train to handle the twin Avco-Lycoming AL5512 engines (4,200 shp).

XH-49 

Original designation of UH-46B.

Canadian versions

CH-113 Labrador 

Search and rescue version of the Model 107-II-9 for the Royal Canadian Air Force.

CH-113A Voyageur 

Assault and utility transport version of the Model 107-II-28 for the Canadian Army. Later converted to CH-113A Labrador when the Canadian Forces acquired the CH-47 Chinook.

Swedish versions

HKP 4A 

Boeing Vertol 107-II-14, used originally by Air Force for SAR, ten built.

HKP 4B 

Boeing Vertol 107-II-15, mine-layer/ASW/SAR helicopter for Navy, three built and one conversion from Boeing-Vertol civil prototype.

HKP 4C 

Kawasaki KV-107-II-16, advanced mine-layer/ASW/SAR helicopter for Navy,eight built.

HKP 4D 

Rebuilt HKP 4A for Navy as SAR/ASW helicopter, four conversions.

Japanese versions

KV-107II-1 (CT58-110-1)

Utility transport version, one built from Boeing-supplied kits.

KV-107II-2 (CT58-110-1)

Commercial airline version, nine built from Boeing-supplied kits.

KV-107IIA-2 (CT58-140-1)

Improved version of the KV-107/II-2, three built.

KV-107II-3 (CT58-110-1)

Minesweeping version for the JMSDF, two built.

KV-107IIA-3 (CT58-IHI-10-M1)

Uprated version of the KV-107/II-3, seven built.

KV-107II-4 (CT58-IHI-110-1)

Assault and utility transport version for the JGSDF, 41 built.

KV-107II-4A (CT58-IHI-110-1)

VIP version of the KV-107/II-4, one built.

KV-107IIA-4 (CT58-IHI-140-1)

Uprated version of the KV-107/II-4, 18 built.

KV-107II-5 (CT58-IHI-110-1)

Long-range SAR version for the JASDF, 17 built.

KV-107IIA-5 (CT58-IHI-104-1)

Uprated version of the KV-107II-5, 35 built.

KV-107II-7 (CT58-110-1)

VIP transport version, one built.

KV-107II-16

HKP 4C for Swedish Navy. Powered by Rolls-Royce Gnome H.1200 turboshaft engines, eight built.

KV-107IIA-17 (CT58-140-1)

Long-range transport version for the Tokyo Metropolitan Police Department, one built.

KV-107IIA-SM-1 (CT58-IHI-140-1M1)

Firefighting helicopter for Saudi Arabia, seven built.

KV-107IIA-SM-2 (CT58-IHI-140-1M1)

Aeromedical and rescue helicopter for Saudi Arabia, four built.

KV-107IIA-SM-3 (CT58-IHI-140-1M1)

VIP transport helicopter for Saudi Arabia, two built.

KV-107IIA-SM-4 (CT58-IHI-140-1M1)

Air ambulance helicopter for Saudi Arabia, three built.