User:Fnlayson/Sikorsky S-xx

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[edit] S-59

This is a sandbox for the new Sikorsky S-59 article.
S-59/XH-39
Type Utility helicopter
Manufacturer Sikorsky
Primary user United States Army
Developed from Sikorsky S-52

The Sikorsky S-59

The Sikorsky H-19, (also known as the S-55) was a multi-purpose helicopter used by the United States Army. It was also license-built by Westland Aircraft as the Westland Whirlwind in the United Kingdom. United States Navy and Coast Guard models were designated HO4S, while those of the U.S. Marine Corps were HRS.

[edit] Design and development

Text 1

Around 1955, the two-blade Bell rotor scored a brilliant victory over the four-blade Sikorsky. In fact, the Model XH-39 (S-59), using a 400shp Continental XT51 turbine, was rejected by the US Army, despite its speed and the advantage of retractable landing gear, as being old-fashioned in design and unsuitable for further development. Instead, the Army chose the Bell XH-40 with a Lycoming XT53 turbine. Nevertheless the four-seat XH-39, with retractable tailwheel landing gear and a new four-blade rotor, broke the world speed record over 3km in 1954 by flying at 251km/h. The ill-fated Sikorsky aircraft had been built using a modified YH-18A airframe, itself derived from the unsuccessful postwar S-52.

G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984

Text 2

In late 1953 the Army awarded Sikorsky a contract for the experimental conversion of two existing H-18 helicopters from piston to turbine power. The two aircraft selected for conversion were 49-2890 and -2891, the third and fourth H-18s built, with the former to be used for flight testing and the latter for static engineering evaluation. Sikorsky allotted the two craft the company designation S-59, and began the conversion work in early 1954.

The H-39 retained the H-18's basic pod-and-boom layout, but differed from the earlier machine in several significant ways. The most obvious difference was, of course, in powerplant. The H-39 was powered by a single 400shp XT51-T-3 Artouste II turbine engine, which drove a new, fully-articulated, four-bladed main rotor. Other changes included a modified tail rotor, strengthening of the fuselage, incorporation of retractable wheeled landing gear, and the addition of updated electronics.

The H-39 was the Army's first turbine-powered helicopter, and was for a time the world's fastest rotorcraft. On 26 August 1954 Army Warrant Officer Billy Wester flew the craft to a new world helicopter speed record of 251kph; less than two months later Wester and his H-39 set a new world helicopter altitude record by reaching 7474m. The H-39 provided the Army with much valuable information on the capabilities of turbine-powered helicopters, and the success of its three-year evaluation was instrumental in bringing Army aviation into the turbine age.

S.Harding "U.S.Army Aircraft since 1947", 1990

Text 3

The Sikorsky Model XH-39 (S-59) was the Army's first turbine-powered helicopter, and was for a time the world's fastest rotorcraft. In late 1953 the Army awarded Sikorsky a contract for the experimental conversion of two existing H-18 helicopters from piston to turbine power. Sikorsky allotted the two craft the company designation S-59, and began the conversion work in early 1954. The Sikorsky aircraft was built using a modified YH-18A airframe, derived from the unsuccessful postwar S-52 project.

The four-seat H-39 retained the H-18's basic pod-and-boom layout. The H-39 was powered by a single 400shp XT51-T-3 Artouste II turbine engine, which drove a new, fully-articulated, four-bladed main rotor. Other changes included a modified tail rotor, strengthening of the fuselage, incorporation of retractable wheeled landing gear, and the addition of updated electronics.

On 26 August 1954 Army Warrant Officer Billy Wester flew the craft to a new world helicopter speed record of 251kph; less than two months later Wester and his H-39 set a new world helicopter altitude record by reaching 7474m.

The H-39 was rejected by the US Army, despite its speed and the advantage of retractable landing gear, as being old-fashioned in design and unsuitable for further development. Instead, the Army chose the Bell XH-40, which soon gained fame as the UH-1 Huey.

Nevertheless the H-39 provided the Army with much valuable information on the capabilities of turbine-powered helicopters, and the success of its three-year evaluation was instrumental in bringing Army aviation into the turbine age.

[edit] Variants

S-59 
XH-39 

[edit] Operators

[edit] Specifications (H-19)

General characteristics

  • Crew: 2 (pilot, copilot)
  • Capacity: 12 troops or 8 litters
  • Length: 62 ft 7 in (19.1 m)
  • Rotor diameter: 53 ft (16.16 m)
  • Height: 13 ft 4 in (4.07 m)
  • Disc area: ft² (m²)
  • Empty weight: 4,795 lb (2,177 kg)
  • Loaded weight: 7,200 lb (3,266 kg)
  • Max takeoff weight: 7,900 lb (3,587 kg)
  • Powerplant:Pratt & Whitney R-1340-57 radial engine, 600 hp (450 kW)

Performance


[edit] References

[edit] External links

[edit] Sikorsky S-69

Main article: Sikorsky S-69

[edit] Design and development

Also known by the military designation XH-59A, the S-69 was part of the Advancing Blade Concept (ABC) program.[1] This Advancing Blade Concept system consisted of two rigid, contra-rotating rotors which made use of the aerodynamic lift of the advancing blades. At high speeds, the retreating blades were offloaded, as most of the load was supported by the advancing blades of both rotors and the penalty due to stall of the retreating blade was thus eliminated. This system did not even require a wing to be fitted for high speeds and to improve manoeuvrability, and also eliminated the need for an anti-torque rotor at the tail.[2], Avia.Russian.ee Website[3]

Text 1

In late 1971 the Army Air Mobility Research and Development Laboratory awarded Sikorsky a contract for the development of a single engine research helicopter prototype designed specifically to flight test the company's Advancing Blade Concept (ABC) rotor system.[2] The resultant Model S-69, which was allotted the military designation XH-59A and the serial number 71-1472, made its first flight in July 1973.

The XH-59A's ABC system consisted of two three-bladed, coaxial, contra-rotating rigid rotors, both of which were driven by the craft's single 1,825shp PT6T 3 Turbo Twin Pac engine.[2] During high speed flight only the advancing blades of each rotor generated lift; this off-loaded the retreating blades and thereby eliminated the aerodynamic restrictions caused by blade-stall and the high mach number effect of the advancing blade tip. This, in turn, produced greater stability and maneuverability while eliminating the need for either a supplementary lift-generating wing or an anti-torque tail rotor_ The XH-59A's streamlined fuselage more closely resembled that of a conventional airplane than a helicopter, having a cantilever tail unit with twin endplate rudders, side-by-side seating for the two crewmen, and fully retractable tricycle landing gear.

The crash of the first XH-59A early in the flight test program led to the construction of a second prototype incorporating several significant control system modifications.[2] This second machine (73 21941) flew for the first time in 1975, and in 1977 was converted into a compound rotorcraft through the installation of two 3.000 lbst J60-P-3A turbojet engines. The modified machine was joint1% evaluated by the Army, Navy and NASA beginning in 1978, and was later able to reach and maintain speeds in excess of 320 mph in level flight. The first prototype was ultimately rebuilt as a compound rotorcraft under a NASA contract and subsequently test flown (with the new serial 73-29142) by mixed Army, Navy, USAF and NASA crews at NASA's Moffet Field, California, test facility. Both XH-59A aircraft were officially transferred to NASA following the 1981 end of joint Army/Navy participation in the tri-partite flight test program.

[edit] S-52

The Sikorsky S-52-1 was the first US helicopter with all-metal rotor blades. A two-seater, it was developed into the three/four-seat S-52-2. Neither model was very succesful.

[edit] Design and development

Text 1

Sikorsky's long and eventful partnership with Army aviation can accurately be said to have started during the Second World War when the company's XR-4, the first helicopter built for military service, was delivered to the USAAC. Two other Sikorsky designs, the R-5 and R-6, also entered Army Air Force service before VJ Day, and all three types made important contributions both to the American war effort and to the development of military rotary-wing doctrine. However, it is the H-18 that holds the distinction of being the first Sikorsky helicopter to be procured for service evaluation by the Army Ground Forces, as distinct from the USAAF.

Design work on the Sikorsky Model S-52 began in late 1945, and the craft made its first flight in the summer of the following year. The first American helicopter to be equipped with all-metal main and anti-torque rotor blades, the S-52 had a semi-monocoque, pod-and-boom type fuselage, a single 175hp Franklin engine, quadricycle wheeled landing gear, and a fully-enclosed cabin that could seat up to three people. The machine's performance was quite impressive by the standards of the day; indeed, the commercial S-52 set three international speed and altitude records in 1948.

The S-52's performance was certainly a factor in the Army's 1949 decision to purchase four examples of the slightly modified Model S-52-2 for service test and evaluation.

S.Harding "U.S.Army Aircraft since 1947", 1990

Text 2

The first US helicopter with all-metal rotor blades, the Sikorsky S-52-1 two-seater was first flown on 12 February 1947, powered by a 133kW Franklin engine. In 1948 it established three international helicopter records for speed and altitude and was developed into the S-52-2, a three/four-seater with a 183kW Franklin O-425-1 engine which was ordered by the US Marine Corps as a replacement for the HO3S.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

Text 3

The S-52's performance was certainly a factor in the Army's 1949 decision to purchase four examples of the slightly modified Model S-52-2 for service test and evaluation. The Army's four YH-18As (serials 49-2888 through -2891) were essentially similar to the standard commercial S-52, differing primarily in their ability to carry a fourth passenger. Extensive testing showed the YH-18A to be quite capable in the light utility and observation roles, but the Army ultimately decided not to procure the type in quantity. One aircraft was later converted into the sole H-39 turbine-powered research helicopter and the S-52-2 eventually served the Navy, Marine Corps and Coast Guard as the HO5S.

S.Harding "U.S.Army Aircraft since 1947", 1990

Text 4

The first US helicopter with all-metal rotor blades, the Sikorsky S-52-1 two-seater was first flown on 12 February 1947, powered by a 133kW Franklin engine. In 1948 it established three international helicopter records for speed and altitude and was developed into the S-52-2, a three/four-seater with a 183kW Franklin O-425-1 engine which was ordered by the US Marine Corps as a replacement for the ÍO3S. Deliveries of the HO5S-1 began in March 1952, and the type served also with the US Coast Guard as the HO5S-1G.

D.Donald "The Complete Encyclopedia of World Aircraft", 1997

[edit] Variants

YH-19

[edit] Operators

[edit] External links