Sikorsky XH-39

XH-39 (S-59)

Sikorsky XH-39
Role	Helicopter
Manufacturer	Sikorsky Aircraft
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

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, CT.^[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, CT.^[3]

In addition to the two XH-39's, 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, CT ^[4]

Variants

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)

S-59 during runup

Sikorsky S-59 on display at the New England Air Museum

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

General characteristics

Crew: Four
Length: 41 ft 0 in (12.50 m)
Rotor diameter: 35 ft 0 in (10.67 m)
Height: 9 ft 7 in (2.92 m)
Disc area: 962 ft² (89.4 m²)
Empty weight: 2,105 lb (957 kg)
Loaded weight: 3,361 lb (1,528 kg)
Powerplant: 1 × Continental CAE XT51-T-3 turboshaft, 400 shp (298 kW)

Performance

Maximum speed: 136 knots (156 mph, 251 km/h)
Cruise speed: 120 knots (138 mph, 222 km/h)
Range: 243 NM (280 mi, 451 km)
Service ceiling: 17,900 ft (5,460 m)
Disc loading: 3.49 lb/ft² (17.1 kg/m²)
Power/mass: 0.12 hp/lb (0.20 kW/kg)

References

Notes

1 2 Polmar and Kennedy 1981, p. 288.
1 2 http://www.sikorskyarchives.com/S-59.php
↑ "Sets Helicopter Record." Popular Mechanics, February 1955, p. 113, bottom of page.
↑ http://neam.org/index.php?option=com_content&view=article&id=882
↑ 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.

External links

Wikimedia Commons has media related to Sikorsky S-59.

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

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 S-23 S-24 S-25 S-26 S-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 RS XBLR-3 XPBS XSS XV-2

Helicopters (company designations)	VS-300 (S-46) S-47 S-48 S-49 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/H-92 S-97 S-300 S-333 S-434

Helicopters (military designations)	SH-3 HH-3E/F R-4 H-5 H-6 H-18 H-19 H-34 CH-37 XH-39 HH-52A CH-53 CH-53E CH-53K CH-54 HH-60G HH-60J MH-60R/S SH-60B/F SH-60J/K UH-60 VH-60 RAH-66 CH-124 CH-148

Experimental aircraft	Cypher Cypher II Firefly 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; US Army 1948–1956 and 1962–present; US Navy 1962–present

Main 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/J 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

Main joint sequence
(1962–present)

1962 redesignations	OH-13/UH-13J UH-19 CH-21 OH-23 UH-25 CH-34 CH-37 HH-43

New designations	CH-46/HH-46/UH-46 CH-47 UH-48 XH-49 QH-50 XH-51 HH-52 CH-53/HH-53/MH-53/CH-53E/CH-53K CH-54 TH-55 AH-56 TH-57 OH-58 XH-59 UH-60/SH-60/HH-60/HH-60J YUH-61 XCH-62 YAH-63 AH-64 HH-65 RAH-66 TH-67 MH-68 H-69¹ ARH-70 VH-71 UH-72 H-73 to H-89¹ MH-90 H-91¹ VH-92

1962 redesignations
reusing old numbers

¹ Not assigned

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