XH-39 (S-59)
Sikorsky XH-39
Role Helicopter
Manufacturer Sikorsky Aircraft
First flight 26 August 1954
Introduction not produced
Primary user United States Army
Number built 1[1]
Developed from Sikorsky S-52

The Sikorsky XH-39 (manufacturer designation S-59), developed by Sikorsky Aircraft in 1954, was the U.S. Army's first turbine-powered helicopter. It was fast and innovative, but ultimately rejected by the United States Army in favor of the Bell UH-1 Iroquois.

Design and development

S-59 during runup

The four-seat XH-39 was powered by one Continental CAE XT51-T-3 400 shp (298 kW) turboshaft engine, a license-built development of the Turbomeca Artouste. It was developed from a previous Sikorsky model, the H-18 (company model S-52), and had the same layout. It differed in using retractable landing gear, modified tail rotor, and four-blade main rotor.[1] In the end, the U.S. Army selected the Bell XH-40, prototype of the UH-1 Huey. Two YH-18As were modified into XH-39s; one for flight testing and the other for static test.

On 26 August 1954, the XH-39 set a world helicopter speed record of 156.005 mph (251 km/h) over a three kilometer closed course at Bradley Field (now Bradley International Airport) in Windsor Locks, Connecticut.[2] The same year, on October 17, 1954, it set an unofficial world helicopter altitude record of 24,500 ft (7,474 m) at Bridgeport, Connecticut.[3]

In addition to the two XH-39s, one S-59, serial number 52004, registration number N74150, was produced for use for company demonstration flights.[2] It has been restored and is now on display at the New England Air Museum, Windsor Locks, Connecticut.[4]

Variants

Sikorsky S-59 on display at the New England Air Museum
XH-39
Former YH-18A modified for static testing, not flown and later modified back to YH-18A standard.
XH-39A
Former YH-18A modified for flight testing.

Specifications (XH-39)

3-view line drawing of the Sikorsky XH-39

Data from U.S. Army Aircraft Since 1947[5]

General characteristics

  • Crew: One
  • Capacity: 3 passengers
  • Length: 41 ft 0 in (12.50 m)
  • Height: 9 ft 7 in (2.92 m) (to top of rotor head)
  • Empty weight: 2,105 lb (955 kg)
  • Gross weight: 3,361 lb (1,525 kg)
  • Powerplant: 1 × Continental CAE XT51-T-3 turboshaft, 400 shp (300 kW)
  • Main rotor diameter: 35 ft 0 in (10.67 m)
  • Main rotor area: 962 sq ft (89.4 m2)

Performance

  • Maximum speed: 156 mph (251 km/h, 136 kn)
  • Cruise speed: 138 mph (222 km/h, 120 kn)
  • Range: 280 mi (450 km, 240 nmi)
  • Service ceiling: 17,900 ft (5,500 m)

See also

Related development

Aircraft of comparable role, configuration, and era

Related lists

References

Notes

  1. 1 2 Polmar and Kennedy 1981, p. 288.
  2. 1 2 "Sikorsky Archives | S-59".
  3. ↑ Hearst Magazines (February 1955). "Sets Helicopter Record". Popular Mechanics. Hearst Magazines. p. 113.
  4. ↑ "New England Air Museum".
  5. ↑ Harding 1990, p. 233.

Bibliography

  • Harding, Stephen. U.S. Army Aircraft Since 1947. Shrewsbury, England: Airlife, 1990. ISBN 1-85310-102-8.
  • Polmar, Norman and Floyd D. Kennedy, Jr. Military Helicopters of the World: Military Rotary-wing Aircraft Since 1917.. Annapolis, Maryland: Naval Institute Press, 1981. ISBN 0-87021-383-0.
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