A National Historic VS-300 Helicopter (1939) The American Society of Engineering Landmark May 17, 1984 Mechanical Engineers Crystal City, Virginia American Helicopter Society

VS-300 Helicopter (1939) INTRODUCTION Mr. Sikorsky, however, never abandoned In 1938, Igor Sikorsky’s proposal to de- Igor I. Sikorsky’s VS-300 was America’s his dream of building a helicopter and re- velop a helicopter to test his theories was first practical helicopter. It was also the sumed development work in 1928. The accepted by United Aircraft, parent corpo- first successful helicopter in the world to lighter materials and improved aviation ration of Sikorsky Aircraft since 1929. The pioneer the now familiar single main rotor engines then available allowed him to VS-300 was designed in the spring of with torque-compensating tail rotor de- conclude that a successful, practical heli- 1939 and built that summer. sign. This became the standard configura- copter would soon become possible. He tion used by most of the world’s helicopter submitted a patent application in 1931 for On September 14, 1939, Igor Sikorsky pi- manufacturers ever since. a helicopter design that was similar to, loted the first test flight of the VS-300 and included nearly all the major features from the property of the Vought-Sikorsky The development of the VS-300 estab- of, the VS-300. The patent was granted in plant in Stratford, Connecticut. lished the concepts and principles that 1935. were utilized in the design of the VS-316 Over the next several years, the aircraft (Sikorsky R-4), the first production heli- Prior to this time, a number of experimen- demonstrated its practicality and served copter. This marked the beginning of the tal helicopters appeared (along with other as an experimental prototype. It was the world’s rotorcraft industry. categories of rotorcraft such as autogyros first successful helicopter in the world to and gyroplanes). However, none of these have a single main rotor. exhibited all of the characteristics that are HISTORICAL PERSPECTIVE expected in a helicopter: stability, control, The principal designer of the VS-300 was speed, autorotational landing and lack of Igor lvanovich Sikorsky, born May 25, excessive vibration. 1889, in the Russian city of Kiev. At the age of twelve, he made a rubber band- The first successful helicopter to fly in Eu- powered flying model of a helicopter. rope (and probably in the world) was the Seven years later, he began experimental French Breguet-Dorand “Gyroplane Labo- study of rotorcraft principles and had ratore” of 1935 which had a dual coaxial completed the design and construction of main rotor. Two side-by-side main rotors a 25 hp Anzani-powered coaxial rotor heli- mounted on outriggers were used for the copter in July, 1909. A second one was Focke-Achgelis Fw-61 which was initially completed in February, 1910. Although flown in Germany in 1936 and is con- both of these helicopters exhibited the sidered to be the world’s first practical ability to produce lift, it was evident that helicopter. Another German helicopter, much further effort and expense would be the Flettner synchrocopter was produced required to develop such a machine to the for military use between 1942 and 1945. point that it could lift off with a pilot This aircraft, sometimes referred to as an aboard. Consequently, Igor Sikorsky de- “eggbeater” type, had its twin main rotors cided upon a career of developing fixed- mounted on skewed shafts and required wing aircraft. This career eventually in- its rotating blades to synchronize with one cluded designing the world’s first four- another. engined airplane (the “Grand Baltic” of 1913) in Russia and the large flying boat airliners of the 1930’s and early 1940’s in the United States. VS-300 DEVELOPMENT Late in 1938, lgor Sikorsky won approval from United Aircraft to develop a research helicopter. On March 12, 1939, he submit- ted a proposal which described a single- rotor helicopter, powered by a 75 hp piston engine and estimated at a cost of The first tethered flight of the VS-300 in $60,000 to design, construct and demon- its second configuration was made on strate a successful helicopter with satis- March 6, 1940. Roll and pitch control factory control characteristics. were provided by adding two lifting (hori- zontal) tail rotors which had differential Construction of the Vought-Sikorsky-300 collective pitch. Each rotor was 40 inches VS-300 began in late March of 1939. This in radius. The azimuth control was re- first configuration had a three-bladed moved from the main rotor, leaving only main rotor, 28 feet in diameter, and was collective pitch control. Control of the air- powered by a four cylinder, air-cooled, craft was now satisfactory except in for- 75 hp Lycoming engine. Its fuselage was ward flight. It was in this configuration that the VS-300 made its first free flight on an open framework of welded steel tubing covering of the fuselage frame was first May 13, 1940, and was publicly demon- with controls and an open pilot’s seat. The experimented with at this time and found strated for the first time on May 20, 1940. power transmission consisted of V-belts to offer favorable effects. and bevel gears. The anti-torque tail rotor By July, a 90 hp Franklin engine was in- was single-bladed and 40 inches in Since the principles of good control ware stalled and experimental development of radius. On September 14,1939. then understood, the fourth and final con- the aircraft progressed into the following Mr. Sikorsky piloted the first flight of the figuration of the VS-300 was established year. After the attachment of rubber pon- VS-300 from the property of the Vought- in order to achieve a simpler aircraft. The toons, the VS-300 made the world’s first Sikorsky plant in Stratford, Connecticut. horizontal tail rotor was removed and full helicopter water landings on April 17, The duration of the flight was approx- cyclic pitch control given to the main rotor. 1941. On May 6, Igor Sikorsky piloted the imately ten seconds and the altitude at- The first flight in this configuration was VS-300 to establish the International tained was a few inches. By November of made on December 8, 1941. Various de- Helicopter Endurance record of 1 hour, 32 1939, sustained flights were being made, sign options intended for future applica- minutes and 26 seconds. but the control and stability charac- tion to production helicopters were teristics of the aircraft were described as experimented with in the VS-300 during By mid-August of 1941, the VS-300 had being marginal. the following two years. By September of been altered into its third major configura- 1943, the final version of the aircraft had tion. Longitudinal control was provided by The helicopter sustained severe damage achieved speeds of up to 80 mph. a single lifting tail rotor. Lateral control on December 19, 1939, rolling over on the was achieved by restoring cyclic pitch to ground after being caught in a gust of On October 7, 1943, Igor Sikorsky pre- the main rotor through a swashplate. Both wind while hovering. It was believed that sented the VS-300 to Henry Ford at the the lifting and the anti-torque rotors were control was the basic problem here, and a Edison Museum in Dearborn, Michigan. It two-bladed and 46 inches in radius at this different tail rotor concept was explored in had logged a total flight time of 102 time. Eventually, a three-bladed lifting tail the VS-300’s second configuration. hours, 34 minutes and 51 seconds. rotor was installed. This configuration was believed to have given the best control characteristics to the VS-300. Fabric ACKNOWLEDGMENTS The American Society of Mechanical Engineers The Sikorsky VS-300 Helicopter is the Frank M. Scott, President 69th National Historic Mechanical Engi- Dr. Ernest B. Gardow, Vice President, Region I neering Landmark to be designated since William H. Coleman, Vice President, Region III the ASME program began in 1973. In addi- Alan M. Letzt, Chairman, Washington D.C. Section tion, 16 International and seven Regional William Rowe, History and Heritage, Washington D.C. Section Landmarks have been recognized. Each Dr. Burke E. Nelson, Chairman, Fairfield County Section represents a progressive step in the evolu- Dr. Joseph C. De France, History and Heritage, Fairfield County Section tion of mechanical engineering, and each Paul F. Allmendinger, Executive Director reflects its influence on society, either in its immediate locale, nationwide or American Helicopter Society throughout the world. Joseph Mallen, Chairman of the Board Richard B. Lewis, II, President The landmarks program illuminates our John Zugschwert, Executive Director technological heritage and serves to en- Ray Prouty, Historian courage the preservation of the physical remains of historically important works. It United Technologies Sikorsky Aircraft provides an annotated roster for engi- William F. Paul, President neers, students, educators, historians Robert Zincone, Executive Vice President and travelers and helps establish per- sistent reminders of where we have been ASME National History and Heritage Committee and where we are going along the diver- Dr. R. Carson Dalzell, P.E., Chairman gent paths of discovery. Curator Robert M. Vogel, Secretary (Smithsonian Institution) ASME is grateful to the American Heli- Dr. Robert B. Gaither copter Society and United Technologies Dr. Richard S. Hartenberg, P.E. Sikorsky Aircraft for their assistance with Dr. J. Paul Hartman, P.E. this designation. Dr. Merritt Roe Smith

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