The US Army's fleet of Chinook helicopters will be getting a bit more muscle over the next decade as Boeing ramps up for construction and testing of three CH-47F Block II airframes as part of a modernization program. The US$276 million Army contract will see the introduction of new technologies into the vintage Chinook that will provide it with more lifting power and a stronger fuselage.

Among the ever changing makes and mods of aircraft that come and go, there are a few that just keep on keeping on after hitting the aerospace engineering sweet spot. One of these is the Boeing Chinook, which first flew in 1961 and has been ferrying troops, artillery and supplies for over 25 nations for 55 years.

To extend the life of the venerable twin-rotor design, Boeing is adding a series of improvements to the CH-47F variant. Currently at the demonstration and validation phase, the fuselage is reinforced at critical areas for greater structural integrity at less weight and there's an improved, more efficient drivetrain to deliver more power to the new swept-tip Advanced Chinook Rotor Blades

Made of a composite material a sporting a new geometry, these rotors provide 1,500 lb (680 kg) more lifting capacity on their own. To further improve payload, the six fuel tanks have been consolidated into two for more fuel and less weight.

Boeing says that work on the first test helicopter will begin in 2018 with testing in 2019. If all goes according to schedule, the first Block II Chinook will be delivered in 2023 and 500 Chinooks will eventually be upgraded to Block II configuration.

"The Army's only heavy-lift helicopter exists to deliver decisive combat power for our ground commanders," says Colonel Greg Fortier, US Army project manager for Cargo Helicopters. "The Cargo family is anxious to build upon Colonel Rob Barrie's efforts to establish this critical program and deliver an adaptive air vehicle. Increasing payload capacity today enhances battlefield agility and prepares the Chinook for even greater performance gains in the future."