Sikorsky S-52
S-52 | |
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Sikorsky S-52-3 | |
Role | Helicopter |
Manufacturer | Sikorsky Aircraft |
First flight | 12 February 1947 |
Introduction | April 1951 |
Primary users | United States Navy United States Army United States Marine Corps United States Coast Guard |
Number built | 93[1] |
Variants | Sikorsky XH-39 Vertical Hummingbird |
The Sikorsky S-52 is a utility helicopter developed by Sikorsky Aircraft in the late 1940s. It was used by the U.S. Navy, Marines, and Coast Guard.[2] The S-52 was the first US helicopter with all-metal rotor blades. A two-seater, it was developed into the four-seat S-52-2. It was designated HO5S-1 by the U.S. Navy and Marine Corps; HO5S-1G by the Coast Guard; and YH-18A by the Army.
Design and development[]
Sikorsky Aircraft began designing the S-52 in late 1945.[3] The prototype S-52, first flown in 1947, was a two-seater and used a 178 hp (133 kW) Franklin air-cooled flat-six piston engine.[2]
The two-seat version was modified into the S-52-2, a four-seat helicopter using a 245 hp (183 kW) Franklin O-425-1 air-cooled flat-six. It had a semi-monocoque fuselage of pod-and-boom arrangement with a large bubble-like front greenhouse,[1] a three-blade rotor, and quadricycle fixed landing gear. The production S-52-3 (HO5S-1) incorporated a downward sloping (anhedral) v-tail stabilizer.[4] It also had sliding doors on the right forward 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.[5] The pilot-in-command occupied the right front seat.
The first American helicopter to have all-metal rotor blades,[1][2] the prototype[2] 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 (1,100 yd) circuit, and an absolute height of 21,220 ft (6,468 m).[1] 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.[1] The S-52 was the first helicopter to be flown in a loop, as flown by Harold E. Thompson on 19 May 1949.[6]
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) and retractable tricycle gear.[1]
Operational history[]
The Navy operated the aircraft as a utility type, and it was used by the Marines for observation and scouting in Korea,[7] where the HO3S proved more popular. Four S-52s were evaluated by the United States Army for utility use in 1950, as the YH-18A, but not purchased in quantity.[3]
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.[citation needed]
Variants[]
![](http://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Sikorsky_YH-18A.jpg/220px-Sikorsky_YH-18A.jpg)
- S-52-1
- Two-seat prototype, first flown in 1948.[8]
- S-52-2
- Improved three/four-seat variant.[8]
- S-52-3
- Variant of the S-52-2 for the United States Navy and Coast Guard, designated HO5S-1 and HO5S-1G.[9]
- YH-18A
- Four S-52-2s for evaluation by the United States Army,[3] two later converted into XH-39s.[10]
- HO5S-1
![](http://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Sikorsky_HO5S%E2%80%911.jpg/220px-Sikorsky_HO5S%E2%80%911.jpg)
- Model S-52-3, a United States Navy variant of the four-seat S-52-2, 79 built.[9]
- HO5S-1G
- As HO5S-1 for the United States Coast Guard, eight built.[9]
- Vertical Hummingbird
- Sold by Vertical Aviation Technologies of Sanford, Florida, the Hummingbird 260L is a kit-built design using the basic airframe, blades, main transmission, and tail rotor drive of the Sikorsky S-52 helicopter, but streamlined with a Bell 206 JetRanger nosecone and windshields. The Hummingbird is powered by a Lycoming VO-435—a vertically mounted, opposed six-cylinder 435-cubic-inch engine.[12]
Operators[]
- United States Army[3]
- United States Coast Guard[14]
- United States Marine Corps[citation needed]
- United States Navy[citation needed]
Specifications[]
Data from Jane's All The World's Aircraft 1951–52.[15]
General characteristics
- Crew: two
- Capacity: two passengers or two stretchers
- Length: 27 ft 5 in (8.36 m) (fuselage length)
- Height: 8 ft 8 in (2.64 m)
- Empty weight: 1,650 lb (748 kg)
- Gross weight: 2,400 lb (1,089 kg)
- Max takeoff weight: 2,700 lb (1,225 kg) (overload)
- Fuel capacity: 62 US gal (230 l; 52 imp gal)
- Powerplant: 1 × Franklin 6V6-245-B16F air-cooled six-cylinder horizontally-opposed piston engine, 245 hp (183 kW)
- Main rotor diameter: 33 ft 0 in (10.06 m)
- Main rotor area: 855 sq ft (79.4 m2)
Performance
- Maximum speed: 110 mph (180 km/h, 96 kn) at sea level
- Cruise speed: 96 mph (154 km/h, 83 kn)
- Range: 415 mi (668 km, 361 nmi)
- Service ceiling: 15,500 ft (4,700 m)
- Rate of climb: 1,300 ft/min (6.6 m/s)
See also[]
Related development
Related lists
References[]
Notes[]
- ^ Jump up to: a b c d e f Polmar and Kennedy, p. 288.
- ^ Jump up to: a b c d Donald 1997, p. 840.
- ^ Jump up to: a b c d Harding 1990, p. 228.
- ^ FAA type certificate
- ^ Flight manual, page 5
- ^ Guinness World Records 2019. Portable Press, 2019. p. 164. ISBN 9781684127184.
- ^ Polmar and Kennedy, p. 289 caption.
- ^ Jump up to: a b "Sikorsky S-52 Series – A Successful Little Helicopter and its Background". Flight International. 7 August 1953. p. 178.
- ^ Jump up to: a b c Andrade 1979, p. 195
- ^ Andrade 1979, p. 119
- ^ Andrade 1979, p. 122
- ^ Hummingbird Helicopter Archived 23 November 2009 at the Wayback Machine. vertical-aviation.com.
- ^ Hagedorn 1986, p. 63.
- ^ Pearcy 1991, pp. 292–293.
- ^ Bridgman 1951, pp. 289c–290c.
Sources[]
- FAA Type Data Certificate, Helicopter Specification No. 1H2, rev. 3; 7 July 1961.
- GAA Rotorcraft Flight Manual for Model S-52-3 Helicopter, Publication No. SA4045-10 Register 2, Sikorsky Aircraft Division of United Aircraft, 1952.
- Bridgman, Leonard. Jane's All The World's Aircraft 1951–52. London: Sampson Low, Marston & Company, Ltd, 1951.
- Donald, David, ed. "Sikorsky S-52". Encyclopedia of World Aircraft. Etobicoke, Ontario: Prospero Books, 1997. ISBN 1-85605-375-X.
- Hagedorn, Daniel P. "From Caudillos to COIN" Air Enthusiast, Thirty-one, July–November 1986. pp. 55–70.
- Harding, Stephen. "Sikorsky H-28". U.S. Army Aircraft Since 1947. Shrewsbury, England: Airlife, 1990. ISBN 1-85310-102-8.
- Pearcy, Arthur. U.S. Coast Guard Aircraft Since 1916. Shrewsbury, England: Airlife, 1991. ISBN 1-85310-118-4.
- Polmar, Norman, and Floyd D. Kennedy, Jr. Military Helicopters of the World. Annapolis, MD: Naval Institute Press, 1981. ISBN 0870213830.
External links[]
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- 1950s United States helicopters
- Single-engined piston helicopters
- 1950s United States military utility aircraft
- Sikorsky aircraft
- Aircraft first flown in 1947