The Sikorsky CH-53 line of heavy-lift helicopters have been dutifully serving the US Marine Corps since the mid-1960s and even the most recent iteration of the venerable Stallion line is about ready to be put out to pasture. But Sikorsky has a new powerhouse waiting in the wings.

Sikorsky began the Stallion line back in 1966 with the original Sea Stallion. It was joined by the current-gen Super Stallion in 1981, though the OG Sea Stallion was retired in 2012 so right now the Super is all we've got. However, Sikorsky is not resting on its laurels. The company is currently contracted with the USMC to deliver the third generation Stallion by 2019. Hail to the King, baby.

The CH-53K King Stallion is isn't just a simple replacement for the existing model, it's practically a whole new chopper. Granted, the King has the same outside dimensions as its predecessor (it does need to fit into the same aircraft carrier hangers that the Super currently does) but it's nearly unrecognizable in the cockpit and under the hood thanks to a slew of retrofits and upgrades.

The 200 or so new 53K's ordered by the USMC will feature twice the external lifting capacity of the Super Stallions—that's a total of 27,000 pounds or 13.5 short tons or two 463L master pallets or nearly four M777 Howizters—and three times the overall lift capacity at 35,000 pounds. This is made possible by a trio of 7,500 SHP GE engines—each 57 percent more powerful than its predecessor while consuming 20 percent less fuel—and the chopper's seven, 35 foot-long carbon composite blades. Even under load, the King Stallion's speed will top out at 200 knots (230 mph), 30 knots faster than the existing Super. What's more, the new King will sport a 12,500 pound gearbox assembly—which alone weighs more than an entire Blackhawk helicopter.

The King's interior is also receiving a 21st century update including a new digital glass cockpit with fly-by-wire controls and a new elastomeric hub system. These improvements will shrink the area consumed by control panels by 15 percent and actually widen the cabin interior by a full foot.

"The rollout of the CH-53K helicopter introduces a new era in Marine Corps aviation and is an exciting milestone in our company's 91-year history," Sikorsky President Mick Maurer said in a statement. "The CH-53K aircraft will effectively triple the external load carrying capacity of the CH-53E aircraft — to more than 27,000 pounds over a mission radius of 110 nautical miles. With its 88,000-pound maximum gross weight, powerful new engines, lightweight composite structure, new rotor blades and fly-by-wire flight controls, the CH-53K will have the means to move troops and equipment from ship to shore, and to higher altitude terrain, more quickly and effectively than ever before."

Ground test began in earnest last month, though there are hundreds of hours more needed before the King takes its first flight. The USMC hopes to have 200 such CH-53Ks retrofitted and deployed by 2019, at a cost of nearly $25 billion. [PopSci - Sikorsky - Stars and Stripes - Wiki]