According to the information available to me, Igor Sikorsky was a Russian-American aviation pioneer who is credited with advancing helicopter design and pioneering the use of helicopters for commercial and military purposes.
He designed, built, and flew the VS-300, which is considered to be the world's first successful single-rotor helicopter. He also founded Sikorsky Aircraft Corporation in 1925, which became a leading manufacturer of helicopters and other aircraft.
Throughout his career, Sikorsky designed and developed numerous helicopter models. Some of the most notable helicopters he created include:
1. VS-300: The VS-300 was Sikorsky's first successful single-rotor helicopter, which he flew in 1941. It had a single main rotor and a tail rotor to counteract torque.
2. R-4: The R-4 was a single-rotor helicopter designed for the United States Army during World War II. It was the first helicopter to be mass-produced and widely used in military operations.
3. S-51: The S-51 was a multi-purpose helicopter designed and built by Sikorsky Aircraft in 1946. It was the first helicopter to be certified for civilian use and saw extensive use in military, commercial, and civil aviation.
4. S-55: The S-55 was a larger and more powerful version of the S-51, developed in 1949. It was widely used for various purposes, including passenger transportation, search and rescue, and military utility.
5. H-19 Chickasaw: The H-19 Chickasaw was a military utility helicopter designed and built by Sikorsky Aircraft in the early 1950s. It was widely used by the United States military during the Korean War and later in other military and civil operations.
6. S-61: The S-61 was a medium-sized, twin-engine helicopter developed by Sikorsky Aircraft in 1959. It was primarily designed for military use but was also used in civil applications, such as offshore oil rig operations and search and rescue.
These are just a few examples of the helicopters designed by Igor Sikorsky. Throughout his career, he contributed significantly to the advancement of helicopter technology and the establishment of the helicopter as a viable means of transportation and utility in various fields.