SIKORSKY S-55/H-19 CHICKASAW and WESTLAND WHIRLWIND.
Sikorsky S-55/H19 Chickasaw & Westland Whirlwind.
The S-55 was deemed to be the first completely successful design for helicopter entrepreneur Igor Sikorsky, the type first entering service with all three United States services in the early 1950s Korean War years and going into mass production, seeing service with vast number of countries worldwide.