Sikorsky R-4B Hoverfly
A production R-4B on Okinawa in 1945.
Image source: Robert Kastner from WWII Pacific War Eagles by Jeff Ethell and Warren Bodie. Used with permission.
The first helicopter produced in quantity for the U.S. military forces, the Sikorsky R-4 was developed from the pre-war VS-300 model. The prototype, designated the XR-4 by the USAAF, first flew on 14 January, 1942, powered by a 165 hp Warner R-500 radial engine.
The XR-4 had a single main rotor 36 feet in diameter and a single anti-torque tail rotor. The enclosed cockpit seated two side-by-side with full dual controls. Flying controls were similar to modern helicopters with a cyclic stick, collective pitch lever and rudder pedals for control of the tail rotor.
In 1943, the engine was replaced with a Warner R-550 of 180 hp and the main rotor diameter increased to 38 feet. The same year, the XR-4 made the first landing by a helicopter on a ship at sea, the aircraft carrier USS Bunker Hill.
Given the company designation VS-316A by Sikorsky, thirty were ordered for service trials by the USAAF, three as YR-4As and 27 as YR-4Bs. After tests in both tropical and arctic conditions, three were allocated to the U.S. Coast Guard and seven were sent to the British.
The final production version was the R-4B, 100 of which were ordered in late 1943. Twenty of these went to the U.S. Navy and Coast Guard as HNS-1 for reconnaissance and air/sea rescue missions. Another 45 were supplied to Britain, where they were known as the Hoverfly Mark I.
In 1945, near the end of the war, several R-4Bs saw active service in Burma.
The Ghost Squadron's R-4B is in need of a correct engine and other powertrain components before it can be fully restored to its original condition and placed on static display.
One Pilot and Passenger
One Warner R-550-1/3 Engine
Max. Speed 75 mph @ Sea Level
Climb to 8,000 ft in 45 minutes
Length 48' 1" including rotor
Max. Weight 2,540 lbs
Normal Range 130 miles
is a registered trademark of the Commemorative Air