The Boeing CH-47 Chinook is a versatile, twin-engine, tandem rotor heavy-lift helicopter. The contra-rotating rotors eliminate the need for an anti-torque vertical rotor, allowing all power to be used for lift and thrust. Its top speed of 170 knots (196 mph, 315 km/h) was faster than utility and attack helicopters of the 1960s and even many of today. Its primary roles include troop movement, artillery emplacement and battlefield resupply. There is a wide loading ramp at the rear of the fuselage and three external-cargo hooks. It has replaced the CH-54 Tarhe as a lifter.
A commercial model of the Chinook, the Boeing-Vertol Model 234, is used worldwide for logging, construction, fighting forest fires and supporting petroleum exploration operations. As of December 15, 2006 Columbia Helicopters, Inc of Aurora, Oregon has purchased the Type certificate of the Model 234 from Boeing.[2] Currently the company is seeking FAA issuance of a Production Certificate to produce parts with eventual issuance of a PC to produce aircraft.
Development
[YHC-1A
The original Model 107/YHC-1A was rejected by the Army as being too small for its needs. The YHC-1A was then evaluated by the U.S. Marine Corps, and ordered as the HRB-1 (CH-46A after 1962).
CH-47A The all-weather medium-lift CH-47A Chinook entered service in Vietnam about 1966. The CH-47A was powered initially by Lycoming T55-L-5 engines rated at 2200 shp (1,640 kW) but then replaced by the T55-L-7 rated at 2650 shp (1,980 kW) engines or T55-L-7C engines rated at 2,850 shp. The CH-47A had a maximum gross weight of 33,000 pounds. 349 built.
A/ACH-47A Originally known as the Armed/Armored CH-47A (or A/ACH-47A) (officially designated ACH-47A by US Army—Attack Cargo Helicopter—and unofficially "Guns A Go-Go"), four CH-47A helicopters were converted to gunships by Boeing Vertol in late 1965. Three were assigned to the 53rd Aviation Detachment in South Vietnam for testing, with the remaining one retained in the U.S. for weapons testing. By 1966, the 53rd was redesignated the 1st Aviation Detachment (Provisional) and attached to the 228th Aviation Support Helicopter Battalion of the 1st Air Cavalry Division. By 1968, only one gunship remained, and logistical concerns prevented more conversions. It was returned to the United States, and the program stopped. The ACH-47A carried five M60D 7.62x51 mm machine guns or M2HB .50 caliber machine guns, provided by the XM32 and XM33 armament subsystems, two M24A1 20 mm cannons, two XM159B/XM159C 19-Tube 2.75" rocket launchers or sometimes two M18/M18A1 7.62x51 mm gun pods, and a single M75 40 mm grenade launcher in the XM5/M5 armament subsystem (more commonly seen on the UH-1 series of helicopters). The surviving aircraft, Easy Money, has been restored and is on display at Redstone Arsenal, near Huntsville, Alabama.
CH-47B
CH-47B CH-47B was powered by two AlliedSignal Engines T55-L-7C 2850 shp (2,130 kW) engines. The CH-47B featured a blunted rear rotor pylon, redesigned asymmetrical rotor blades, and strakes along the rear ramp and fuselage to improve flying characteristics. The CH-47B was the standard troop transport used by the 1st Cavalry Division in Vietnam. The Chinook could be equipped with two door-mounted M60D 7.62 mm NATOmachine guns on the M24 armament subsystem and a ramp-mounted M60D using the M41 armament subsystem. Some CH-47 "bombers" were equipped to drop tear gas or napalm from the rear cargo ramp onto NLF (aka Việt Cộng) bunkers. The CH-47 could be equipped with a hoist and cargo hook. The Chinook proved especially valuable in "Pipe Smoke" aircraft recovery missions. The "Hook" recovered about 12,000 aircraft valued at over $3.6 billion during the war. 108 built.
CH-47C
CH-47C Three variants of the "C model" were in evidence. The original "C" had Lycoming T55-L-7C engines delivering 2,850 shp. The "Super C" included Lycoming T55-L-11 engines delivering 3,750 shp, an upgraded maximum gross weight of 46,000 pounds and a pitch stability augmentation system (PSAS). Due to difficulties with the T55-L-11 engines, which were hurriedly brought to war to increase payload, they were temporarily removed from the "Super C" prior to 1970 and the very reliable Lycoming T55-L-7C's were installed until the L-11 engine difficulties could be quantified and corrected. This L-7C engine configuration was affectionately referred to as the "baby C" although it was still a Super C. It still distinguished itself from the "C" in that it had PSAS, and an uprated maximum gross weight. The CH-47 A, B, and all variants of the C were not able to receive certification from the FAA for civil use due to the non redundant hydraulic flight boost system drive. A redesign of the hydraulic boost system drive was incorporated in the CH-47D which allowed that model to achieve FAA certification as the Boeing Model 234. 233 CH-47Cs were built.
The CH-47 A,B, and all variants of the C saw wide use during the Vietnam war. They replaced the H-21 Shawnee in the combat assault support role.
CH-47C Plus Export version of the CH-47C Chinook for the Italian Army.
CH-47D
CH-47D The CH-47D was originally powered by two T55-L-712 engines, but most are now fitted with the T55-GA-714A. Models CH-47A, CH-47B, and CH-47C, all used the same airframe, but later models featured upgraded engines. With its triple-hook cargo system, the CH-47D can carry heavy payloads internally and up to 26,000 pounds externally, for example, bulldozers and 40-foot containers, at speeds over 155 mph (250 km/h). In air assault operations, it often serves as the principal mover of the 155 mm M198 howitzer, 30 rounds of ammunition, and an 11-man crew. Like most US Army helicopters, the Chinook has advanced avionics and electronics, including the Global Positioning System.
The CH-47D saw wide use in Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom in Iraq. The Chinook was used in air assault missions, inserting troops into fire bases and later bringing food, water, and ammunition. It is typically escorted by attack helicopters such as the Apache for protection. The CH-47D was particularly useful in the mountainous terrain of Afghanistan where high altitudes and temperatures limited the use of the Black Hawk.
The RAF versions of the CH-47D are the Chinook HC.2 and HC.2A.
MH-47D and MH-47E The MH-47 variants are intended for special forces operations and have in-flight refueling, a fast-rope rappelling system and other upgrades. The MH-47D was an early special operations version for the US Army. The current model being used by the US Army is the MH-47E. The MH-47G, derived from the CH-47F, is in development and is expected to replace MH-47D/Es.
The RAF ordered eight Chinook HC.3s in 1995 for the special forces operations role. At a total cost of £259 million these were effectively low-cost equivalents to the MH-47E. This has proved to be a false economy as the helicopters were due to enter service in 1998, but in 2004 have yet to be cleared for anything other than training flights. An additional £130 million is required to make them suitable for their mission.
CH-47SD The CH-47SD is a modified variant of the CH-47D, with extra-large fuel tanks and higher payload capacities. It is in use by the Republic of Singapore Air Force, and the Republic of China.
CH-47DG The CH-47DG is an upgraded version of the CH-47C for the Greek Army.
CH-47F The CH-47F, an upgraded D model, first flew in 2001 and the first production model was rolled out on June 15, 2006 at the Boeing facility in Ridley Park, Pennsylvania, and had its maiden flight on October 23, 2006.[3] The CH-47F was designed to extend the service life of the Chinook class beyond 2030. Amongst its upgrades are new 4,868 shaft horsepower Honeywell engines (an improvement of over 1,100 hp per engine), improved digital avionics, and a more modern airframe manufacturing process designed to extend operational life, reduce vibration effects and cut maintenance costs. The CH-47F has a maximum payload of 25,000 pounds or 10,615 kg.
The United States Army has ordered 452 of the 'F' models. In February 2007 the Netherlands was the first international customer to order the 'F' model, six helicopters were ordered to expand their current fleet to 17.Additional orders are expected from Canada and the United Kingdom.
MH-47G The MH-47G special forces operations version is in development for the US Army.
HH-47
HH-47 On November 9, 2006, the HH-47, a new variant of the Chinook based on the MH-47G, was selected by the United States Air Force as the winner of the Combat Search and Rescue (CSAR-X) competition. Four development HH-47s will be built, with the first of 141 production aircraft to enter service in 2012.However, as of February 2007 this contract award has come under scrutiny by the GAO and the USAF may recompete the CSAR-X project.
Other export models
CH-47J and CH-47JA The CH-47J is a medium-transport helicopter for the Japan Ground Self Defence Force, and the Japan Air Self Defence Force. The CH-47JA is a long range version of the CH-47J, fitted with enlarged fuel tanks. Both versions are built under licence in Japan by Kawasaki.
CH-147 Eight CH-47C Chinooks were delivered to the Canadian Forces in 1974. The Chinooks were in Canadian service from 1974 to 1991; they were designated CH-147. These aircraft were subsequently sold to the Netherlands and are now operated by the Royal Netherlands Air Force as CH-47Ds. On July 5, 2006, the Canadian government issued a notice that it intends to purchase 16 Chinooks.
Civilian Models
Model 234LR (Long Range) Commercial transport helicopter. The Model 234LR can be fitted out, as an all-passenger, all-cargo, or cargo/passenger transport helicopter.
Model 234ER (Extended Range) Commercial transport version.
Model MLR (Multi Purpose Long Range) Commercial transport version.
Model 234UT (Utility Transport) Utility transport helicopter.
Model 414 The Model 414 is the international export version of the CH-47D. It is also known as the CH-47D International Chinook.
Derivatives
HLH In the 1970s, the Army contracted Boeing to design a Heavy Lift Helicopter (HLH), designated XCH-62A. It appeared to be a scaled-up CH-47 without a conventional body, in a configuration similar to the S-64 Skycrane (CH-54 Tarhe), but the project was soon cancelled. It was given a second examination in the 1980s and was again rejected. The scaled up model of the HLH was scrapped at the end of 2005 at Fort Rucker, Alabama.
