Sikorsky R-4
| R-4 / Hoverfly | |
|---|---|
| A Sikorsky R-4 in a hover | |
| General information | |
| Type | Helicopter |
| Manufacturer | Sikorsky Aircraft |
| Designer | |
| Primary users | United States Army Air Forces |
| Number built | 131 |
| History | |
| Manufactured | 1942–1944 |
| Introduction date | 5 January 1943 |
| First flight | January 14, 1942 |
| Developed from | Vought-Sikorsky VS-300 |
| Developed into | Sikorsky R-6 |
The Sikorsky R-4 is a two-seat light helicopter that was designed by Igor Sikorsky with a single, three-bladed main rotor and powered by a radial engine. The R-4 was the world's first large-scale mass-produced helicopter and the first helicopter used by the United States Army Air Forces, the United States Navy, the United States Coast Guard and the United Kingdom's Royal Air Force and Royal Navy. In U.S. Navy and U.S. Coast Guard service, the helicopter was known as the Sikorsky HNS-1. In British service it was known as the Hoverfly.