Tag Archives: Sikorsky S-51

1 October 1947

A Los Angeles Airways Sikorsky S-51 helicopter takes off from the roof of the Terminal Annex Post Office, 1 October 1947. The Los Angeles Times published this photograph 2 October 1947 with the following caption: “NEW MAIL SERVICE — Los Angeles Airways helicopter shown landing on the roof of Terminal Annex Post office yesterday to inaugurate helicopter air-mail service, the first of its kind in the United States. Two flights daily are planned on this run with another to start Oct. 16.” (Los Angeles Times Photographic Archive/UCLA Library)

1 October 1947: Los Angeles Airways began regularly scheduled air mail service in Los Angeles, using the Sikorsky S-51 helicopter.

“. . . the U.S. Civil Aeronautics Board awarded LAA the route authorities to operate local air mail services in Southern California using the Sikorsky S-51. Before long, LAA was operating a twice-a-day mail service between the main downtown post office and Los Angeles International Airport along with a small package air express service.

“With a fleet of five S-51s, LAA’s first year of operations resulted in 700 tons of mail being carried with approximately 40,000 landings throughout the Los Angeles metropolitan area. The small operation maintained a 95% reliability rate and by the time it began its small package air express service in 1953, it was annually moving nearly 4,000 tons of mail a year.

“In July 1951 the CAB awarded LAA’s reliable helicopter operation the rights for passenger services which started in November 1954 with larger Sikorsky S-55 helicopters while the smaller S-51s continued the mail and small package services. . . .”

Tails Through Timehttp://aviationtrivia.blogspot.com/2010/06/on-1-october-1947-los-angeles-airways.html

The S-51 was a commercial version of the Sikorsky R-5 series of military helicopters. It was a four-place, single-engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction. The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 41 feet, 7.5 inches (12.687 meters) long. The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.565 meters), giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters). The S-51 had an empty weight of 4,050 pounds (1,837 kilograms) and maximum takeoff weight of 5,500 pounds (2,495 kilograms). Fuel capacity was 100 gallons (378.5 liters).

The helicopter was powered by an air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liter) Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive, nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (Vne) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Of 220 helicopters in the S-51 series built by Sikorsky, 55 were commercial models.

Los Angeles Airways Sikorsky S-51 (Viewliner)
A Los Angeles Airways Sikorsky S-51. The main rotor hub is covered. (Viewliner)

© 2016, Bryan R. Swopes

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4 August 1950

A U.S. Air Force Sikorsky H-5F lifts off during the Korean War. (U.S. Air Force)

4 August 1950: During the Battle of the Pusan Perimeter, wounded soldiers were evacuated from the battlefield by helicopter for the first time when a Sikorsky H-5F of Detachment F, 3rd Air Rescue Squadron, United States Air Force, flew out Private 1st Class Claude C. Crest, Jr., U.S. Army, from the Sengdang-ni area to an Army hospital. By the end of combat in 1953, 21,212 soldiers had been medevaced by helicopters.

Only the second military helicopter, the H-5 was frequently flown overloaded and outside of its center of gravity limits. The helicopter was not armed, though the pilot normally carried an M1911 .45-caliber semi-automatic pistol, and the crewman, a .30-caliber M1 Carbine.

Eleven civil Sikorsky S-51 helicopters had been purchased in 1947 and designated R-5F. This was later changed to H-5F. It was a four-place, single engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction. The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left. (The advancing blade is below the axis of rotation.)

The helicopter’s fuselage was 41 feet, 7.5 inches (12.687 meters). The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters), giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters). The S-51 had an empty weight of 4,050 pounds (1,837 kilograms) and maximum takeoff weight of 5,500 pounds (2,495 kilograms). Fuel capacity was 100 gallons (378.5 liters).

The H-5F was powered by an air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liter) Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive, nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The H-5F had a maximum speed (Vne) of 107 knots (123 miles per hour/198 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914 meters).

Sikorsky H-5, Korea. (U.S. Air Force)
Sikorsky H-5, Korea. (U.S. Air Force)

© 2016, Bryan R. Swopes

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11 March–6 April 1949

Lieutenant Stewart R. Graham, USCG, in cockpit of Sikorsky HNS-1 near Gander, Newfoundland, September 1946. (U.S. Coast Guard)
Lieutenant Stewart R. Graham, USCG, in cockpit of Sikorsky HNS-1 near Gander, Newfoundland, September 1946. (U.S. Coast Guard)

April 6, 1949: Lieutenant Stewart Ross Graham, United States Coast Guard, and his crewman, Aviation Metalsmith 2nd Class (AM2) Robert McAuliffe, completed the longest unescorted helicopter flight on record. They flew a Sikorsky HO3S-1G, serial number 51-234, from the Coast Guard Air Station, Elizabeth, New Jersey, to Coast Guard Air Station Port Angeles, Washington, via San Diego, California, covering a distance of 3,750 miles (6,035 kilometers) in 57.6 flight hours over 11 days.

Lieutenant Graham was the first pilot to fly a helicopter from a ship. On 16 January 1944, he flew a Sikorsky YR-4B, serial number 46445, from the deck of a British freighter, SS Daghestan, while in convoy from New York to Liverpool. After 30 minutes, he returned to the freighter. He was a pioneer in the use of the helicopter by the Coast Guard and the Navy.

U.S. Coast Guard Sikorsky HO3S-1G 51-232. (U.S. Coast Guard)
U.S. Coast Guard Sikorsky HO3S-1G 51-232, sister ship of 51-234. (U.S. Coast Guard)

The HO3S (Sikorsky S-51) was a second-generation helicopter, capable of carrying a pilot and up to three passengers. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction.

The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 41 feet, 7.5 inches (12.687 meters). The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters) giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters).

The S-51 had an empty weight of 4,050 pounds (1,837.05 kilograms) and maximum takeoff weight of 5,500 pounds (2,494.76 kilograms). Fuel capacity was 100 gallons (378.5 liters).

The helicopter was powered by an air-cooled, supercharged, 986.749-cubic-inch-displacement (16.170 liter) Pratt & Whitney R-985 AN-5 (Wasp Jr. T1B4) direct-drive,  nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine had a compression ratio of 6:1 and was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (Vne) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Sikorsky built 220 helicopter of the S-51 series.

U.S. Coast Guard HO3S-1G, serial number 51-238, sister ship of LT Graham’s record-setting helicopter. (USCG/Smithsonian Institution)

© 2017, Bryan R. Swopes

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16 February 1946

The prototype Sikorsky S-51 commercial helicopter, NX19800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)
The prototype Sikorsky S-51 commercial helicopter, NX92800, in flight between Bridgeport and East Hartford, Connecticut, 1946. (Sikorsky Historical Archive)

16 February 1946: The Sikorsky S-51 prototype, NX92800, made its first flight. The test pilot was Dimitry D. (“Jimmy”) Viner, who later made the first civilian rescue using a helicopter. The S-51 was the first helicopter intended for commercial use, though it was also widely used by military services worldwide. (The prototype was later delivered to Aéronavale, French Naval Aviation.)

Dimitry D. ("Jimmy") Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)
Dimitry D. (“Jimmy”) Viner with a Sikorsky S-51, the civil version of the R-5. (Sikorsky Historical Archive)

The S-51 was a commercial version of the Sikorsky R-5 series military helicopters. It was a four-place, single engine helicopter, operated by one pilot. The cabin was built of aluminum with Plexiglas windows. The fuselage was built of plastic-impregnated plywood, and the tail boom was wood monocoque construction.

The main rotor consisted of three fully-articulated blades built of metal spars and plywood ribs and covered with two layers of fabric. (All metal blades soon became available.) The three bladed semi-articulated tail rotor was built of laminated wood. The main rotor turned counter-clockwise, as seen from above. (The advancing blade is on the helicopter’s right.) The tail rotor was mounted on the helicopter’s left side in a pusher configuration. It turned clockwise as seen from the helicopter’s left.

The helicopter’s fuselage was 41 feet, 7.5 inches (12.687 meters). The main rotor had a diameter of 48 feet (14.630 meters) and tail rotor diameter was 8 feet, 5 inches (2.2.565 meters) giving the helicopter an overall length of 57 feet, 1 inch (17.399 meters). It was 13 feet, 1.5 inches (4.001 meters) high. The landing gear tread was 12 feet (3.7 meters).

The S-51 had an empty weight of 4,050 pounds (1,837.05 kilograms) and maximum takeoff weight of 5,500 pounds (2,494.76 kilograms). Fuel capacity was 100 gallons (378.5 liters).

Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (LAT)
Sikorsky S-51 NC92813, Los Angeles Airways, departs on a commercial flight, Los Angeles, California, 1947. (Los Angeles Times)

The helicopter was powered by a 986.749-cubic-inch-displacement (16.170 liter) air-cooled, supercharged, Pratt & Whitney Wasp Jr. T1B4 (R-985 AN-5) direct-drive,  nine-cylinder radial engine which was placed vertically in the fuselage behind the crew compartment. This engine had a compression ratio of 6:1 and was rated at 450 horsepower at 2,300 r.p.m., Standard Day at Sea Level. The R-985 AN-5 was 48.00 inches (1.219 meters) long, 46.25 inches (1.175 meters) in diameter and weighed 684 pounds (310.3 kilograms) with a magnesium crankcase.

The S-51 had a maximum speed (Vne) of 107 knots (123.1 miles per hour/198.2 kilometers per hour). Range was 275 miles (442.6 kilometers). The service ceiling was 14,800 feet (4,511 meters). The absolute hover ceiling was 3,000 feet (914.4 meters).

Of 220 helicopters in the S-51 series built by Sikorsky, 55 were commercial models.

One of Los Angeles Airways' Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)
One of Los Angeles Airways’ Sikorsky S-51 helicopters takes off from roof of the the Terminal Annex Post Office, Los Angeles, California, 1 October 1947. (Los Angeles Times Photographic Archive/UCLA Library)

© 2017, Bryan R. Swopes

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