The Boeing CH-47 Chinook Helicopter was an enlarged development of the Vertol Model 107, designated Model 114, which the Army preferred because of its greater capacity. The prototype CH-47 Chinook Helicopter was first flown on September 21, 1961, and deliveries to the Army began in 1972 as the CH-47A Chinook. With large twin rotors powered by relatively new turboshaft engines, plus a cavernous fuselage, the CH-47 offered helicopter airlift capability not previously available. The Chinook features a cargo carrying fuselage which is basically clear of a obstructions, with the engine and gearbox in pylons above the fuselage and fuel in pods along each side. A large split double door, of which the lower half also acts as a ramp, allows unobstructed rear access for freight or small vehicles. Basic seats are located down each side of the fuselage for 33 troops although up to 55 can be carried. At the end of the Vietnam War one Chinook was reported to have lifted 147 refugees.
The Chinook has been the subject of much engine development. Th CH-47A Chinook had already incorporated an increased power T55 engine, the CH-47B included a further increase in power plus redesigned rotor blades; the CH-47C’s engine was more than three times that fitted to the C-47A and required a strengthened gearbox and increased fuel capacity. Development continued with the CH-47D, with yet another power increase and equipment improvements, including NVG compatibility and the introduction of two additional hooks located under the fuselage to enable multiple underslung loads to be carried. This model proved capable of handling a 25,000lb load, nearly twice the Chinook’s original lift capacity and the Army decided that this was to become their standard model. As a result most of the surviving earlier models underwent a major refurbishment which resulted in nearly about 470 evolving to the CH-47D standard.
A number of Chinooks have been modified for use by the Army’s Special Operations Forces. Designated MH-47, these variants are readily identifiable by the addition of a 29ft 5in refueling probe. Less readily noticeable is the nose borrowed from the commercial Chinook variant giving provision for weather radar. Eleven MH-47Es wer initially ordered and these additionally feature improved communication and navigation capability. No integral armament is fitted but two 6-barrel mini-guns are normally carried for self-protection. Development of an
improved MH-47E commenced I the late 1980s and is recognizable by the larger fuel pods mounted each side of the lower fuselage; this model can also be air-refueled by the tanker version of the C-130 Hercules.
In 2001, it was announced that Special Operations Command were intending to order the MH-47G, which will be rebuilt from existing MH-47Ds with superior navigation equipment. A further plan is to upgrade the CH-47Ds to Ch47F standard. This work will require aircraft remanufacturing and include fitting of more powerful engines, vibration reduction equipment, and improved avionics with integrated digital mission management systems and a digital map.
CH-47 Chinook Helicopters first saw combat duty in Southeast Asia in 1965, and have been the workhorse for Army regular and special ops forces ever since.