Air Force Museum
Sikorsky R-4B Hoverfly II
Developed by Igor Sikorsky from his famous VS-300 experimental helicopter, the R-4 became the world's first production helicopter, and the U.S. Army Air Force's first service helicopter. The prototype XR-4 made its initial flight on Jan. 13, 1942, and as a result of its successful flight tests, the USAAF ordered three YR-4As and 27 YR-4Bs for service testing and flight training.
In depth
History & service
Developed by Igor Sikorsky from his famous VS-300 experimental helicopter, the R-4 became the world's first production helicopter, and the U.S. Army Air Force's first service helicopter. The prototype XR-4 made its initial flight on Jan. 13, 1942, and as a result of its successful flight tests, the USAAF ordered three YR-4As and 27 YR-4Bs for service testing and flight training. Of these, one went to Burma and one to Alaska, while several others were assigned to the U.S. Navy, U.S.
Coast Guard and British Royal Navy. They showed such promise that the USAAF ordered 100 R-4Bs.
The R-4 was first used in combat in May 1944. In a letter to a friend, Col. Philip G. Cochran, commanding officer of the 1st Air Commando Group, wrote "Today the 'egg-beater' went into action and the damn thing acted like it had good sense."
The aircraft in figures
Engine: Warner R-550 of 200 hp · Maximum speed: 75 mph · Cruising speed: 65 mph · Range: 130 miles · Ceiling: 8,000 ft. · Rotor diameter: 38 ft. · Length: 33 ft. 7 3/4 in. · Height: 12 ft. 5 in. · Weight: 2,581 lbs. loaded · Serial number: 43-46506
When a runway is the wrong answer
A helicopter exchanges some of an airplane's speed and efficiency for the ability to hover and land in confined places. Its rotating blades must provide lift and control while moving through changing airflow. The advancing and retreating sides of the rotor experience different conditions, and the pilot manages several controls together. Hovering is an active, demanding state rather than a pause in flight.
That capability changed the possibilities for rescue, medical evacuation, observation, and transport. A casualty no longer always had to reach a conventional airfield before being flown to care. Crews could approach places where roads were slow, damaged, or absent. Yet power, weather, visibility, terrain, and rotor clearance sharply limited what was possible. A successful rescue required judgment as well as a suitable machine.
Early helicopters in these collections show how manufacturers gradually made the idea practical. Their exposed structures and compact cabins make weight and payload compromises easy to see. Later machines carried more people and equipment, but the underlying tradeoff remained: the ability to operate close to the ground could place the crew close to danger. Following the connection from a small civil helicopter to a military rescue aircraft reveals a shared history of handling skill, mechanical development, and people using flight to reach someone who needed help.
