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Sikorsky VS.300

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Russian-born Igor Sikorsky built his first helicopter, powered by a 25hp Anzani engine, in 1909. It would not leave the ground, and a second machine, completed in 1910, was little better; it did rise a short distance, but was incapable of lifting a pilot, and Sikorsky turned his attention to fixed-wing aeroplanes. After the 1917 Revolution he left the country, settling in the United States some two years later, and soon entering the aircraft industry of his new country.

As the era of flying boats faded, lgor Sikorsky revived the idea of developing the helicopter. Once again he was involved in "advanced pioneering work . . . where extremely little reliable information and no piloting experience whatever were available." By the late 1930s changing requirements for military and commercial air transport forecast the termination of the large flying boat, and Sikorsky returned to his first love, the helicopter. The essential aerodynamic theory and construction techniques that had been lacking in 1910, however, were now available. In a memo to the general manager of Vought-Sikorsky (the new name of the company) dated Aug. 10, 1938, he wrote:

"Besides having considerable possibilities as a privately owned aircraft, the direct-lift ship [helicopter] will be a very important service type for the army and navy. For the army, this type of ship would render excellent services for communication, fire control, short-range reconnoitering and bombing operations. For the navy, the ship would be extremely useful as the only aircraft that could take off and land without catapulting from any surface vessel...."

Even though an official manufacturing order had not been issued to begin work on a "new" type of aircraft, helicopter development continued throughout the fall of 1938. lgor Sikorsky and a handful of engineers and production personnel spent lunch breaks and off hours sketching, designing, fabricating and testing various components and systems for what would become known as the VS-300 ("V' for Vought, "S" for Sikorsky and "300" for Sikorsky's third helicopter design).

Rotor tests were encouraging enough for Sikorsky to request a meeting with Eugene Wilson, a senior vice president of United Aircraft, at which he received the go-ahead to construct a prototype helicopter. Sikorsky's argument for building the rotorcraft had been compelling.

"So important is this development to the future of society that it becomes our responsibility to undertake it. While admittedly radical, and possibly 'impossible,' the helicopter is wholly rational. Like no other vehicle, it will operate without regard to prepared landing surfaces. Thus, it will free us of the serious handicap to progress imposed by fixed-wing aircraft-airport limitations. It is not competitive with the airplane, but complementary to it. If Sikorsky does not create this craft of the future, another [company] will. By training and expedence, we are best equipped to do it. And finally, unlike the airplane, the helicopter will be used not to destroy but to save lives!"

Early in 1939, with a well trained engineering group at his disposal, he started the construction of the VS-300 helicopter. As he said later, "There was a great satisfaction in knowing that, within a short period of time, good engineering along a novel line produced encouraging results."

On September 14, 1939, the plane lifted off the ground on its first flight. Its designer was at the controls; during his entire career Sikorsky always insisted on making the first trial flight of any new design himself. At this stage the aircraft was still tethered to the ground and had weights suspended underneath it to help keep it stable.

It was powered by a 4-cylinder Lycoming engine of 75hp, had full cyclic pitch control for the main rotor and a single anti-torque tail rotor at the end of a narrow enclosed tailboom which also supported a large under-fin.

The VS-300 had a three-bladed main rotor, 28 ft / 8.53 m in diameter, a welded tubular steel frame; a power transmission consisting of V-belts and bevel gears; a two-wheel landing gear arrangement and a completely open pilot's seat. A single foot pedal controlled the antitorque tail rotor.

The cyclic control was not fully satisfactory, however, and by the time the VS-300 made its first free flight on 13 May 1940, 3 feet off the ground for 10 sec with 35-foot-long ropes. By now powered by a 90hp Franklin motor, the configuration had changed to an open-framework steel-tube fuselage with outriggers at the tail end. Each of these mounted a horizontally-rotating airscrew to provide better lateral control; the vertical tail screw was retained. Sikorsky tried 19 different configurations before he was satisfied with the final design of the VS-300.

By mid-1940 the VS-300 was staying airborne for 15 min. at a time. Various modifications were made during 1940-41 with three tail rotors, and the replacement of the tail outriggers in June 1941 by a short vertical pylon carrying a single horizontal tail rotor, and the reinstatement in December of a now fully satisfactory cyclic pitch control for the main rotor. Other alterations concerned the arrangement of the main undercarriage and the fitting of nose and tail wheels in place of skids.
Sikorsky VS-300

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On July 18, 1940, a 15-min. flight was made during which the ship hovered. On Jan. 10, 1941, the VS-300 made a flight that lasted more than 25 min., which was believed to be the longest flight ever made by a helicopter in America at that time.

During 1940, Sikorsky removed the cyclic-pitch control, which varies the pitch angle of each blade as it rotates so that the helicopter can be manoeuvred, and substituted two small horizontal ro-tors on outriggers for pitch and lateral control. The modifications proved successful, and on May 6, 1941, this version of the VS-300 had surpassed the Focke -Achgelis's duration record with a flight of 1 hr. 32 min. 26.1 sec.

Les Morris, was the Chief Test Pilot on the Sikorsky VS-300 starting in March, 1941 (and on the XR-4, XR-5 and XR-6 which followed).

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On Apr. 17, 1941, the VS-300 recorded another first by making the world's initial helicopter water landings by fitting pneumatic flotation bags under the main undercarriage wheels.

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In its final form the VS-300 had a 150hp Franklin engine, a fabric-covered fuselage and a tricycle undercarriage.

During its lifetime, the VS-300 logged more than 100 hr. of flight time and demonstrated the concepts and principles that were later utilized in the design of the Sikorsky R-1, the worlds first production helicopter.

In 1943 the VS-300 was delivered to the Henry Ford Museum in Dearborn, Michigan, where it is still housed.

The general manager of Sikorsky Aircraft, Lee S. Johnson, summed up its contribution twenty years later when he said: 'Before Igor Sikorsky flew the VS-300, there was no helicopter industry; after he flew it, there was."

 

 


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