Vought-Sikorsky VS-300

https://en.wikipedia.org/wiki/Vought-Sikorsky_VS-300

The Vought-Sikorsky VS-300 (or S-46) is a single-engine helicopter designed by
Igor Sikorsky. It had a single three-blade rotor originally powered by a 75
horsepower (56 kW) engine. The first "free" flight of the VS-300 was on 13 May
1940. The VS-300 was the first successful single lifting rotor helicopter in the
United States and the first successful helicopter to use a single vertical-plane
tail rotor configuration for antitorque. With floats attached, it became the
first practical amphibious helicopter.

Igor Sikorsky's quest for a practical helicopter began in 1938, when as the
Engineering Manager of the Vought-Sikorsky Division of United Aircraft
Corporation, he was able to convince the directors of United Aircraft that his
years of study and research into rotary-wing flight problems would lead to a
breakthrough. His first experimental machine, the VS-300, was test flown by
Sikorsky on 14 September 1939, tethered by cables. In developing the concept of
rotary-wing flight, Sikorsky was the first to introduce a single engine to power
both the main and tail rotor systems. The only previous successful attempt at a
single-lift rotor helicopter, the Yuriev-Cheremukhin TsAGI-1EA in 1931 in the
Soviet Union, used a pair of uprated, Russian-built Gnome Monosoupape rotary
engines of 120 hp each for its power. For later flights of his VS-300, Sikorsky
also added a vertical airfoil surface to the end of the tail to assist
anti-torque but this was later removed when it proved to be ineffective.

The cyclic control was found to be difficult to perfect, and led to Sikorsky
locking the cyclic and adding two smaller vertical-axis lifting rotors to either
side aft of the tailboom. By varying pitch of these rotors simultaneously, fore
and aft control was provided. Roll control was provided by differential pitching
of the blades. In this configuration, it was found that the VS-300 could not fly
forward easily and Sikorsky joked about turning the pilot's seat around.


Role
Experimental

Manufacturer
Vought-Sikorsky

Designer
Igor Sikorsky

First flight
14 September 1939

Variants
Sikorsky R-4

Sikorsky fitted utility floats (also called pontoons) to the VS-300 and
performed a water landing and takeoff on 17 April 1941, making it the first
practical amphibious helicopter. On 6 May 1941, the VS-300 beat the world
endurance record held by the Focke-Wulf Fw 61, by staying aloft for 1 hour 32
minutes and 26.1 seconds.

The final variant of the VS-300 was powered by a 150 hp Franklin engine. The
VS-300 was one of the first helicopters capable of carrying cargo. The VS-300
was modified over a two-year period, including removal of the two vertical tail
rotors, until 1941, when a new cyclic control system gave it much improved
flight behavior.

In 1943, the VS-300 was retired to the Henry Ford Museum in Dearborn, Michigan.
It has been on display there ever since, except for a trip back to the Sikorsky
Aircraft plant for restoration in 1985.

Specifications (VS-300)

General characteristics
Crew: one
Length: 28 ft 0 in (8.53 m)
Height: 10 ft 0 in (3.05 m)
Gross weight: 1,150 lb (522 kg)
Powerplant: 1 × Franklin 4AC-199-E , 90 hp (67 kW) at 2,500 rpm
Main rotor diameter: 30 ft 0 in (9.14 m)

Performance
Maximum speed: 50 mph (80 km/h; 43 kn)
Range: 75 mi (65 nmi; 121 km)
Endurance: 1 hour 30 minutes


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