Evolution Of Sikorsky Heavy Lift Helicopters...

Note:  Sikorsky is going all out for the roll out of the CH-53K today.  As part of that effort they've put out a timeline of their heavy lift helicopters....pics via Sikorsky....

December 18, 1953
First Flight of the Sikorsky S-56 Helicopter (HR2S-1/H-37) “The Deuce”
Sikorsky’s first multi-engine, retractable main landing gear helicopter becomes the largest piston-engine helicopter ever built. 156 were built.

March 25, 1959
First Flight of the Sikorsky S-60 Helicopter
The S-60, Skycrane®, was a concept demonstrator. Design improvements increased the gross weight while utilizing the dynamic components of the S‑56. Only one was built.

May 9, 1962
First Flight of the S-64 Helicopter (CH-54 “Tarhe”)
Rotor derived from the S-56/S-60. This design expanded maximum gross weight capabilities by another 3,500 pounds in just three short years. The Sikorsky S-64 helicopter was the first production flying crane helicopter and the first helicopter with a fly-by-wire control system. 99 were built.

October 14, 1964
First Flight of the S-65 Helicopter (CH-53A "Sea Stallion")
Based on previous designs;The S‑56 and S‑64 models contributed the basis for dynamic components and the S‑61R provided a basic shape for the S‑65. This design was later modified to the CH‑53D, which had more powerful engines and added engine air particle separators to prevent ingestion of dust. 412 were built.

March 4, 1974
First Flight of the (S‑65) CH-53E “Super Stallion™”
Growth version of the CH‑53D which added a third engine and a seventh main rotor blade, drastically increasing maximum gross weight by 75%. It becomes the largest and most powerful helicopter outside of Russia. 227 were built.

May 5, 2014
Rollout of the Sikorsky CH-53K Helicopter
The Sikorsky CH-53K will be the world’s premier heavy lift helicopter. It is a new design leveraging the lessons learned from almost half a century of manufacturing and operating the CH-53A/D/E models of heavy lift helicopters.
Designed to triple the lift capability of the CH-53E to 110 nm in hot, high conditions, while maintaining the same shipboard footprint and reducing maintenance and operating costs.