XH-39 (S-59)

Sikorsky XH-39
Role	Helicopter Type of aircraft
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

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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

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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)

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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)

References

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Notes

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^ ^a ^b Polmar and Kennedy 1981, p. 288.
^ ^a ^b "Sikorsky Archives | S-59".
^ Hearst Magazines (February 1955). "Sets Helicopter Record". Popular Mechanics. Hearst Magazines. p. 113.
^ "New England Air Museum".
^ Harding 1990, p. 233.

Bibliography

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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.

External links

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Wikimedia Commons has media related to Sikorsky S-59.

"Sikorsky Model XH-39 (S-59)." at Global Security (accessed 12 May 2008)

v t e Sikorsky aircraft
Fixed-wing aircraft (company designations)	S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 S-11 S-12 S-13 S-14 S-15 S-16 S-17 S-18 S-19 S-20 S-21 S-22/23/24/25/26/27 S-28 S-29-A S-30 S-31 S-32 S-33 S-34 S-35 S-36 S-37 S-38 S-39 S-40 S-41 S-42 S-43 VS-44 S-45
Fixed-wing aircraft (military designations)	C-6 C-28 JRS JR2S PS P2S RS XBLR-3 XPBS XSS XV-2
Helicopters (company designations)	VS-300 (S-46) S-47 S-48 S-49 S-50 S-51 S-52 S-53 S-54 S-55 S-56 S-57 S-58 S-59 S-60 S-61 S-61L/N S-61R S-62 S-63 S-64 S-65 S-66 S-67 S-68 S-69 S-70 S-71 S-72 S-73 S-74 S-75 S-76 S-80 S-92 S-95 S-97 S-100 S-102 S-103 S-300 S-333 S-434
Helicopters (military designations)	SH-3 Sea King HH-3E/F R-4 H-5 H-6 H-18 H-19 Chickasaw H-34 Choctaw CH-37 Mojave XH-39 HH-52A Seaguard CH-53 Sea Stallion CH-53E Super Stallion CH-53K King Stallion MH-53 CH-54 Tarhe UH-60 Black Hawk HH-60G Pave Hawk HH-60J/MH-60T MH-60R/S Seahawk SH-60B/F Seahawk H-60J/K VH-60 RAH-66 Comanche VH-92 Patriot CH-124 Sea King CH-148 Cyclone HLH
Experimental aircraft	Cypher/Cypher II Firefly Raider Raider X SB-1 X2 XBLR-3 XV-2

United States helicopter designations, Army/Air Force and Tri-Service systems

Numerical sequence used by USAAC/USAAF/USAF 1941–present; U.S. Army 1948–1956 and 1962–present; U.S. Navy 1962–present

Army/Air Force sequence
(1941–1962)

Prefix R-, 1941–1948	R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16
Prefix H-, 1948–1962	H-5 H-6 H-9 H-10 H-11 H-12 H-13 H-13J H-15 H-16 H-17 H-18 H-19 H-20 H-21 H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-31 H-32 H-33 H-34 H-35 H-36¹ H-37 H-38¹ H-39 H-40 H-41 H-42 H-43 H-44¹ H-45¹

Tri-Service sequence
(1962–present)

1962 redesignations	H-13 H-13F H-13J H-19 H-21 H-23 H-25 H-34 H-37 H-43
New designations	H-46 H-47 H-48 H-49 H-50 H-51 H-52 H-53 CH-53/E/K HH-53/MH-53 H-54 H-55 H-56 H-57 H-58 H-59 H-60 UH-60 SH-60 HH-60 MH-60 H-61 H-62 H-63 H-64 H-65 H-66 H-67 H-68 H-69¹ H-70 H-71 H-72 H-73
Alternate sequence	H-1 AH-1/J/T/W/Z UH-1/N/Y H-2 G H-3 CH-3/HH-3 SH-3 H-4 H-5 H-6 AH-6 MH-6 OH-6
Non-sequential	H-90 H-92 CH-92/VH-92 H-139

¹ Not assigned

Design and development

Variants

Specifications (XH-39)

See also

References

Notes

Bibliography

External links