Boeing is pushing forward to launch a growth version of the 49-year-old CH-47 Chinook airframe in fiscal year 2010, despite a non-committal stance from the US Army.
The company is seeking to win the army's support to build a new airframe powerful enough to haul a 12-13t payload for 400km (215nm), says Jack Dougherty, H-47 programme manager, who adds: "That's something we can grow a Chinook into."
Boeing's current Chinook models have the ability to lift a load of that size, but only for a very small distance, says Dougherty. One notional concept for the proposed growth configuration would strengthen, but perhaps not greatly enlarge, the H-47's airframe.
The current aircraft has a maximum take-off weight of 25,400kg (56,000lb), but the army limits this to 22,700kg to reduce its maintenance burden.
Boeing would propose to fill this extra payload capability with fuel and make the airframe sturdier, allowing the helicopter to carry its maximum payload on a 400km route.
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© SPC Gul Alisan/US Army |
The new design also may require a more powerful engine, Dougherty says. Boeing's options include a growth version of the Honeywell T55-714, or a version of the 6,000shp (4,480kW) Rolls-Royce T406.
Alternatively, Boeing could increase the Chinook's growth weight to 27,200kg, with a 660mm (26in) plug inserted into the airframe, Dougherty says. Should the army ask for a 31,700kg airframe, Boeing would have to adopt an all-new, wider airframe for the Chinook, as well as upgrade its propulsion system and drive train.
Dougherty says Boeing's plan is to gain support for the growth model in the army's next six-year spending plan, which starts in FY2010. The company believes it can launch the growth version within the same budget line as the army's procurement account for the current CH-47F. This strategy may offer Boeing the advantage of launching a new airframe without facing a competitive threat from Sikorsky, which may be prepared to offer the CH-53K in development for the US Marine Corps.
The army is currently focused on supporting the initial fielding of the CH-47F (below), which achieved the "first unit equipped milestone" with 12 helicopters on 14 August. "We just fielded this [model] and we're not looking for another one yet," says Col William Crosby, the service's incoming deputy programme executive officer for aviation.
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Crosby adds that the army has no requirement for a growth version of the Chinook, but says the service "would love to have it" if the funding were available.
Boeing views the growth Chinook as a separate initiative to the army's existing Joint Heavy Lift requirement for a 25-30t lift capability.
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Source: Flight International
