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2013-08-01

CH47 F Chinook

The CH-47F is an advanced multi-mission helicopter for the U.S. Army and international defense forces. It contains a fully integrated, digital cockpit management system, Common Aviation Architecture Cockpit and advanced cargo-handling capabilities that complement the aircraft’s mission performance and handling characteristics

Its primary mission is to move troops, artillery, ammunition, fuel, water, barrier materials, supplies and equipment on the battlefield. Its secondary missions include medical evacuation, disaster relief, search and rescue, aircraft recovery, fire fighting, parachute drops, heavy construction and civil development.

Current status

Recently U.S. army and Boeing signed a $4 billion multi-year contract for 177 CH-47F Chinook helicopters, with the Army holding options that could increase its total buy to 215 aircraft. Deliveries from the agreement, which is a cost-effective alternative to annually contracting for the aircraft, will begin in 2015.

The tandem-rotor Chinook is the backbone of combat, logistics and humanitarian operations for the U.S. Army and 18 other operators around the world. This order would eventually bring the Army’s CH-47F total procurement close to its target of 464 aircraft, including 24 to replace peacetime attrition aircraft. The US Army’s current inventory stands at 241 F-model aircraft.

There are 15 Army active duty and National Guard units operating the CH-47F, and a 16th is currently being

Current status

Recently U.S. army and Boeing signed a $4 billion multi-year contract for 177 CH-47F Chinook helicopters, with the

Army holding options that could increase its total buy to 215 aircraft. Deliveries from the agreement, which is a cost-effective alternative to annually contracting for the aircraft, will begin in 2015.

There are 15 Army active duty and National Guard units operating the CH-47F, and a 16th is currently being equipped. CH-47F units have logged more than 86,000 combat hours in Afghanistan, maintaining an operational readiness rate of over 80 percent while conducting air assault, transport, and medical evacuation and support missions.

Background

The first in the long line of Chinooks was the YHC-1B tandem-rotor transport helicopter that rolled out in 1961. It was designed to serve the US Army and Air Force as a medium-lift helicopter and evolved into several versions.

Chinook helicopters were introduced in 1962 as the CH-47 Chinook, and models A, B and C were deployed in Vietnam. As the product of a modernization program, which included refurbishing existing CH-47s, the first CH-47Ds were delivered in 1982 and were produced until 1994. A central element in the Gulf War, they continue to be the standard for the U.S. Army in the global campaign against terrorism.

Chinooks first were used in combat in 1965 during the Vietnam conflict. During the last days of the war, one Chinook is reported to have carried 147 refugees in a single lift. CH-47A, B and C models served with distinction for a decade until the war’s end in 1975.

During 2002, Boeing was developing the CH-47F, scheduled for first production in 2004, and was under contract to modernize at least 300 Chinooks to the new F-model standard, which features reduced vibration effects, an integrated cockpit control system and more powerful engines with digital fuel controls. These improvements will make the Chinook fully compatible with 21st century operational and war-fighting requirements and improve the aircraft’s efficiency and effectiveness.

Design

The Chinook is a most reliable and efficient transport helicopter, capable of handling useful loads up to 24,000 pounds (10,886 kg) and a maximum gross weight of up to 50,000 pounds (22,668 kg). Its tandem rotor configuration also provides exceptional handling qualities that enable the CH-47 to operate in climatic, altitude and crosswind conditions that typically keep other helicopters from flying.

The aircraft fuselage is approximately 50 feet long. With a 60-foot rotor span, on each rotor system, the effective length of a CH-47 (with blades turning) is approximately 100 feet from the most forward point of the forward rotor to the most rearward point on the aft rotor.

Maximum airspeed is 170 knots with a normal cruise speed of 130 knots. However, speed for any mission will vary greatly depending on load configuration (internal or external), time of day, or weather conditions.

The minimum crew for tactical operations is four, two pilots, one flight engineer, and one crew chief. For more complex missions, such as NVG operations and air assaults, commanders may consider using five crew members and add one additional crew chief.

The effectiveness of the Chinook has been continually upgraded by successive product improvements, the CH-47A, CH-47B, CH-47C, and CH-47D. The amount of load a cargo helicopter can carry depends on the model, the fuel on board, the distance to be flown, and atmospheric conditions.

Versions

CH-47A - In July 1962 DoD re-designated all U.S. military aircraft and the HC-1B was re-designated the as the CH-47A. Early production CH-47A were operated with the 11th Air Assault Division during 1963 and in October of that year the aircraft was formally designated as the Army’s standard medium transport helicopter. CH-47As deployed to Viet Nam were equipped with Lycoming T55-L7 engines generating 2650 shp.

CH-47B - CH-47B was introduced by Boeing after a production run of over 350 CH-47As. The B model introduced the Lycoming T55-L7C engine, a beefed up airframe. Nonsymmetrical rotor blades, and the blunted aft pylon for better stability. Boeing began delivering the CH-47B in May of 1967 and eventually produced a total of 108 B models before production shifted to the CH-47C.

CH-47C - The CH-47C Chinook model has a maximum cargo hook capacity of 20,000 pounds. The CH-47C has only a single cargo hook below the center of the aircraft. When hooking a single load, soldiers use the main hook. They must coordinate closely with the aircrew as to which hooks to use when carrying multiple loads. The planning figure for the fore and aft hooks is 10,000 pounds each. Designed to meet an Army requirement to transport a 15,000 pound sling load over a 30 mile radius, the C model boasted an increased gross weight to 46,000 pounds, increased fuel capacity, the Lycoming T55-L11 engine developing 3750 shp, and addition structural improvements. The first C model flew in late 1967 and became the mainstay of the Chinook fleet until the advent of the CH-47D.

CH-47D - The CH-47D was the result of June 1976 contract for a modernized Chinook. After the Vietnam war, Boeing and the US Army began planning a major fleet upgrade that led to development of the CH-47D. Almost 500 early model Chinooks went through an extensive modernization process that produced an essentially new CH-47 fleet. Boeing completed first D-model deliveries in 1982 and concluded the program in 1994. Only two U.S. Army CH-47Ds were built to replace aircraft losses during the Persian Gulf War. All other D models are modernized aircraft.

Improvements included upgraded power plants, rotor transmissions, integral lubrication and cooling for the transmission systems, and fiberglass rotor blades. Other improvements included a redesigned cockpit to reduce pilot workload, redundant and improved electrical systems, modularized hydraulic systems, an advanced flight control system, and improved avionics. The Chinook has two tandem three-bladed counter-rotating fiberglass rotors. The CH-47D is powered by two Allied Signal Engines T55-L-712 3750 shp turbo-shaft engines and has a maximum speed of 163 mph (142 knots). The CH-47D is equipped with an air-to-air refueling probe. The Chinook can accommodate a wide variety of internal payloads, including vehicles, artillery pieces, 33 to 44 troops, or 24 litters plus two medical attendants. The Chinook can be equipped with two door mounting M60D 7.62mm machine guns on the M24 armament subsystem and a ramp mounting M60D using the M41 armament subsystem. The “D” model can carry up to 26,000 pounds externally. The CH-47D has three cargo hooks: a center (main) hook and two additional hooks fore and aft of the main hook.

The CH-47D Chinook was a central element in U.S. Army operations in the Persian Gulf War, where more than 160 Chinooks carried U.S. and Allied troops to outflank Iraqi forces and cut off their retreat from Kuwait. During 2002, the Chinook’s high speed and large payload gave it the lowest cost-per-ton-mile of any transport helicopter available.

CH-47F - The U.S. Army Modernization Program calls for 525 Chinooks, which includes a combination of 464 New-Build and Remanufactured CH-47F aircraft and 61 M-47G Remanufactured aircraft. The CH-47F Chinook helicopter has been certified combat-ready by the U.S. Army and fielded to the first operational unit in July 2007. Its tandem rotor configuration also provides exceptional handling qualities that enable the CH-47 to operate in climatic, altitude and crosswind conditions that typically keep other helicopters from flying.

Future

The CH-47F/MH-47G modernization program is now in full-rate production, and will ensure this tandem rotor medium-lift helicopter remains in the US Army fleet at least through the 2030s. It is conceivable that Chinooks will be army aviation assets for a century or more. In addition, Chinooks have served the armed forces of more than 18 international customers and performed in commercial service around the world.

Reference / Photo credit: www.boeing.com / www.fas.org

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