SIKORSKY ARCHIVES PHOTO
To help solve that problem, Sikorsky’s team designed and
built the first helicopter simulator, Test Rig #4950. Sikorsky and aerodynamicist Serge Gluhareff (who would share VS-300 test-pilot duties) would use it to learn a new skill: how to fly a helicopter. To power the VS-300’s three-blade, 28-ft.-diameter
(8.5-m-diameter) main rotor and 40-in.-diameter (1-m-diameter) tail rotor, Sikorsky acquired a 1939 Lycoming four-cylinder piston O-145-C3. Team members bought it secondhand at a local airport, Sikorsky’s son Sergei told ROTOR. “Te whole program was fairly low budget, low priority at the beginning,” he said. Begun as a mid-1800s manufacturer of sewing machines
and bicycles, the company that became Lycoming started producing automobile and truck engines in 1907. After Charles Lindbergh’s 1927 solo transatlantic flight, the com- pany began making aircraft engines. Te O-145 was Lycoming’s first horizontally opposed, air-cooled engine. Te O-145-C3 was its most powerful version, producing 75 hp. (56 kW) at 3,100 rpm. Mounted horizontally, Engine No. 510 powered the VS-300
through a V-belt transmission. On Sep. 14, 1939, Sikorsky flew the VS-300 in its first tethered flight. Te aircraft rose
a few inches during the 10-second flight at the Stratford, Connecticut, plant. Trough 1939, the team tweaked the VS-300 continually, resolving control and stability issues. Tethered flights continued until Dec. 19, 1939, when the prototype was damaged severely in a rollover. Te VS-300’s second configuration added arms to a new,
steel-tube tail boom that supported two horizontal tail rotors for pitch and roll control. (Te main rotor’s cyclic control was removed because of controllability issues.) Te O-145-C3 went to work again on Mar. 6, 1940, when the redesigned VS-300 flew in a tethered flight. On May 13, 1940, before the public in Bridgeport, Connecticut, Sikorsky lifted off the VS-300 in its first free flight. Engine 510 logged fewer than 50 hours through Jul. 22, 1940.
At that point, Vought-Sikorsky sold it for $225. “Tey had enough experience to realize they needed more horsepower,” Sergei Sikorsky said. An Aircooled Motors Franklin 4AC-199-E replaced it. Te air-cooled, four-cylinder horizontally opposed Franklin
produced 90 hp. (67 kW) at 2,500 rpm. It powered the VS-300 through April 1941, when an upgraded 4AC-199 was installed, achieving 90 hp. (67 kW) at 2,680 rpm and 100 hp. (75 kW) at 3,050 rpm. Franklin engines powered the VS-300’s 1941
The VS-300 was modified almost daily during the early test flights that preceded its first free flight on May 13, 1940. An early major change was the addition of outrigger booms off the tail to support two small, horizontal rotors added to correct pitch and roll problems.
DECEMBER 2022 ROTOR 45
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68
