Sikorsky S-52
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| S-52 | |
|---|---|
 Sikorsky S-52 |
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| Type | Helicopter |
| Manufacturer | Sikorsky Aircraft |
| Maiden flight | 12 February 1947 |
| Introduced | April 1951 |
| Primary users | United States Navy United States Army United States Marine Corps United States Coast Guard |
| Number built | 93 (including four Army trials aircraft)[1] |
| Variants | Sikorsky S-59 |
The Sikorsky HO5S-1 (company model S-52) was a utility helicopter developed by Sikorsky Aircraft in 1950, used by the U.S. Navy, Marines, and Coast Guard (as the HO5S-1G).[2]
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[edit] Design and development
The prototype S-52, first flown in 1947, was a two-seater and used a 178 hp (133 kW) Franklin air-cooled flat-6 piston engine (like that used in the Tucker Torpedo).[3]
It was modified as the S-52-2, a four-seat helicopter using a 245hp (183 kW) Franklin O-425-1 air-cooled flat-6. It had a semi-monocoque fuselage of pod-and-boom arrangement with large bubble-like front greenhouse,[4] three-blade rotor, and quadricycle fixed landing gear. The production S-52-3 (HO5S-1) incorporated a downward sloping (anhedral) v-tail stabilizer.[5] It also had sliding doors on the forward front and left rear sides, and a vertically split front bubble, allowing the left half to swing open in a clamshell fashion. The engine was placed at the aft end of the cabin and was canted forward 30 degrees to couple with the clutch and transmission.[6] The pilot in command occupied the right front seat.
The first American helicopter to have all-metal rotor blades,[7] the prototype[8] set several speed and height records in 1948, including 129.6 mph (204.2 km/h) on a 3 km (2 mi) course, 122.75 mph (197.54 km/h) on a 1 km (1100 yd) circuit, and absolute height 21,220 ft (6468 m).[9] It was capable of hover out of ground effect at 5,900 ft (1,798 m) or 9,200 ft (2,804 m) in ground effect.[10] The S-52 is widely believed to be the first helicopter to be looped, as flown by Harold E. Thompson in 1949.
The S-52 also served as the basis of the turbine-powered S-59, which as the XH-39 competed for and lost the contract that produced the Bell UH-1 Iroquois. This aircraft differed in having a four-bladed rotor (against the S-52's three)[11] and retractable tricycle gear.[12]
[edit] Operational history
The Navy operated the aircraft as a utility type, and it was used by the Marines for observation and scouting in Korea,[13] where the HO3S proved more popular. Four S-52s were evaluated by the United States Army for utility use, as the H-18, but not purchased in quantity.[14]
Many of the former military HO5S-1 units were demilitarized, rebuilt, and licensed as civil aircraft by Orlando Helicopters, who acquired the parts inventory from Sikorsky. A successor operation, Vertical Aviation Technologies based at the Orlando-Sanford airport in Florida, now offers a kit-built "Hummingbird" helicopter based upon the Sikorsky design, using many Sikorsky components such as the rotor head, blades, and transmissions, with some changes to the doors, nose, tail, and trim system, and the substitution of a more modern Lycoming engine.[15]
[edit] Operators
[edit] Specifications
General characteristics
- Crew: 2
- Capacity: 2 troops
- Length: 39 ft 2½ in (11.95 m)
- Main rotor diameter: 33 ft in (10 m)
- Height: 9 ft 9½ in (2.99 m m)
- Empty weight: 1650 lb (749 kg)
- Gross weight: 2700 lb (1226 kg)
- Powerplant: 1 × Franklin 6V6-245-B16F (Military O-425-1) air-cooled flat-6 piston engine, 245 hp (186 kW)
Performance
- Maximum speed: 110 mph (176 km/h)
- Cruise speed: 96 mph (154 km/h)
- Range: 415 miles (668 km)
- Service ceiling: 15,500 ft (4,724 m)
- Rate of climb: 1,300 ft/min (6.6 m/s)
[edit] See also
Related development
Related lists
[edit] References
[edit] Notes
- ^ Polmar, Norman, and Kennedy, Floyd D., Jr. Military Helicopters of the World (Annapolis, MD: Naval Institute Press, 1981), p.288.
- ^ Donald, David, ed. Encyclopedia of World Aircraft, (Etobicoke, Ontario: Prospero Books, 1997), p. 840, "Sikorsky S-52".
- ^ Donald, p. 840, "Sikorsky S-52".
- ^ Polmar and Kennedy, p.288.
- ^ FAA type certificate
- ^ flight manual at page 5
- ^ Polmar and Kennedy, p.288; Donald, p.840, "Sikorsky S-52".
- ^ Donald, p.840, "Sikorsky S-52".
- ^ Polmar and Kennedy, p.288.
- ^ Polmar and Kennedy, p.288.
- ^ Polmar and Kennedy, p.288.
- ^ Polmar and Kennedy, p.288.
- ^ Polmar and Kennedy, p.289 caption.
- ^ Harding 1990, p.228.
- ^ Vertical Aviation Technologies, Inc
[edit] Sources
- FAA Type Data Certificate, Helicopter Specification No. 1H2, rev. 3, July 7, 1961
- GAA Rotorcraft Flight Manual for Model S-52-3 Helicopter, Publication No. SA4045-10 Register 2, Sikorsky Aircraft Division of United Aircraft, 1952.
- Donald, David, ed. Encyclopedia of World Aircraft, p.840, "Sikorsky S-52". Etobicoke, Ontario: Prospero Books, 1997. ISBN 1-85605-375-X.
- Harding, Stephen. U.S. Army Aircraft Since 1947. Shrewsbury, England: Airlife, 1990. ISBN 1-85310-102-8.
- Polmar, Norman, and Kennedy, Floyd D., Jr. Military Helicopters of the World. Annapolis, MD: Naval Institute Press, 1981. ISBN 0-870321-383-0.
[edit] External links
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