Boeing CH-47 Chinook

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.

Chinooks have been sold to 16 nations, the largest users are the U.S. Army and the Royal Air Force (see Boeing Chinook (UK variants)). The H-47 is now sold by Boeing Integrated Defense Systems.

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. Currently the company is seeking FAA issuance of a Production Certificate to produce parts with eventual issuance of a PC to produce aircraft.

Chinook CH-47D of the Royal Netherlands Air Force

Boeing CH-47 Chinook Variants

CH-47A

• 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. 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 NATO machine 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.

Source: Wikipedia