User:BillCJ/Sandbox/Sikorsky S-60
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| S-60 | |
|---|---|
| Type | Cargo helicopter |
| Manufacturer | Sikorsky |
| Maiden flight | March 25 1959 |
| Status | Crashed in April 1961 |
| Primary user | United States Navy |
| Number built | 1 |
| Developed from | CH-37 Mojave |
The Sikorsky S-60 prototype "sky-crane" was derived from the S-56 in 1958. Its development led to the larger, turbine-engined CH-54 Tarhe military transport helicopter, and its civil S-64 Skycrane variant.
Contents |
[edit] Development
[edit] Design
The S-60 was equipped with an autopilot for stable hover, and featured a skeletal fuselage with a crew cockpit; the copilot could swivel his seat to face both fore and aft, and control it from either position. The skeletal nature of the helicopter allowed it to carry customizable, underslung 'modules' - nearly 100 troops, a medical outpost, a radar structure, etc.
[edit] Text 1
In May 1958, Sikorsky began work on an experimental "flying crane" helicopter, the "S-60", derived from the S-56 (HR2S-1 / H-37 Mohave) heavy-lift helicopter.[1] The S-60 inherited the S-56's rotor system and twin "power modules", each with a Pratt & Whitney (P&W) R-2800 Double Wasp radial piston engine, but had a stripped-down fuselage with long "taildragger" landing gear that allowed it to straddle cargoes. The crew operated from a glassed-in nose module; the copilot could swing his seat around to face the back to keep an eye on sling loads, controlling the helicopter in this position with an alternate set of controls. The S-60 had an automatic stabilization system to allow it to hover precisely, using inputs from a sidestick controller.
The S-60 performed its first flight on 25 March 1959.[1] It was intended only as a proof-of-concept demonstrator, since the company believed that a production machine would need to be powered by turboshaft engines for greater lift capability. Igor Sikorsky envisioned his flying crane carrying specialized modules or "pods", such as a field hospital or a radar station, as well as general heavy cargoes.
In any case, the company demonstrated the S-60 to the US Army and US Navy during 1960.[1] The military had already worked on the development of flying crane helicopters in the early 1950s, though they were unable to bring a machine to production. The Navy was interested in demonstrations of the S-60 towing a minesweeping sled, and particularly interested in demonstrations in which it hauled cargoes between ship and shore.
With the Navy intrigued, Sikorsky began to move ahead on the production machine.[1] The first obstacle was that a suitable turboshaft powerplant wasn't available. There were two engines under development that seemed like they could be adapted to the task, including the General Electric (GE) T64 turboshaft and the P&W JT12 turbojet. The problem with the GE T64 was that it had a front power shaft, and Sikorsky required a rear power shaft. GE didn't feel there was enough of a market to justify developing another major variant of the T64. The problem with the JT12 was that it would require substantial work to turn it into a turboshaft. However, both Sikorsky and P&W were members of the United Aircraft (UA) industrial group, and senior UA managers immediately committed to building a turboshaft based on the JT12.
The S-60 was lost in a crash in April 1961, but by that time the prototype for the turboshaft-powered "S-64 Skycrane" was already being built.[1] The US military hadn't provided as much support as hoped for, but the West German government had decided to evaluate the S-64 and bought two of the first three evaluation machines built, the third being retained by Sikorsky for development testing.
The initial prototype had a general configuration along the lines of that of the S-60, but was a generally new machine.[1] The cockpit had accommodations for pilot, copilot, and a rearward-facing crane operator / assistant pilot, plus folding seats for two passengers. It was powered by twin P&W JFTD-12A turboshafts with 3,020 kW (4,050 SHP) each, and had a six-bladed main rotor system, with a four-bladed tail rotor. The tricycle landing gear had single wheels on each assembly. There was a retractable tail bumper.
The S-64 performed its initial flight on 9 May 1962. The Germans didn't place orders following their evaluation, but the US Army became interested enough in the machine to place an order for six "S-64A" helicopters for evaluation in June 1963, with the service designation "YCH-54A Tarhe".[1] They were similar to the prototypes, but had production P&W T73-P-1 (notice the military designation) turboshafts with 3,360 kW (4,500 SHP) each.
[edit] Text 2
In 1958 Sikorsky began design work on the Model S-60 twin-engined heavy-lift helicopter, a machine that incorporated the pod-mounted piston engines and dynamic components of the earlier Model S-56/CH-37.[2] The S-60's fuselage was extremely simple, consisting of a central 'backbone' which supported the podded engines, main and tail rotor systems, and a nose-mounted crew cabin. Bulk cargo and passengers were intended to be carried in large rectangular pods that could be attached to the underside of the aircraft's central spine, whereas vehicles and other out-sized loads were to be sling-hoisted. One S-60 was built for Navy evaluation, but the craft was found to be underpowered for its intended roles and Sikorsky took the design back to the drawing boards for extensive reworking. The reconfigured machine, which was allotted the company designation S-64A, made its first flight in May 1962 under the watchful eyes of Army observers.
[edit] Text 3
Sikorsky's first 'flying crane' helicopter was the Sikorsky S-60, developed from the S-56 and retaining that machine's powerplant, transmission and rotor system. Work began in May 1958 and the prototype was flown on 2 March 1969; it was capable of lifting a 5443kg payload beneath the fuselage boom, and the co-pilot could turn his seat to face aft to control loading and unloading. The prototype S-60 crashed in April 1961, but by then Sikorsky had begun construction of an enlarged version, with a six-bladed main rotor driven by two 3020kW JFTD-12A turboshaft engines. Designated S-64, the prototype flew on 9 May 1962.
D.Donald "The Complete Encyclopedia of World Aircraft", 1997
[edit] Specifications (CH-37 Mojave)
This aircraft article is missing some (or all) of its specifications. If you have a source, you can help Wikipedia by adding them.- Note: Data for the S-60 is not available. The S-60 is similar in size to the S-56/CH-37, from which it was derived.
Data from The Complete Encyclopedia of World Aircraft[3]
General characteristics
- Crew: 3
- Capacity: 26 troops
- Length: 88 ft 0 in (26.8 m)
- Rotor diameter: 72 ft 1 in (22.0 m)
- Height: 22 ft in (m)
- Disc area: 4,080 ft² (379 m²)
- Empty weight: lb (kg)
- Max takeoff weight: 21,000 lb (9,500 kg)
- Powerplant: 2× Pratt & Whitney R-2800-54 "Double Wasp" radial engines, 2,100 hp (1,600 kW) each
Performance
- Maximum speed: 131 mph (114 knots, 211 km/h)
- Range: 247 mi (215 nm, 400 km)
- Service ceiling 8,000 ft (m)
[edit] References
The initial version of this article was based on a public domain article from Greg Goebel's Vectorsite.
[edit] External links
[edit] See also
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Related development
Related lists
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Category:Military helicopters H-37 Mojave Category:Vietnam War aircraft
