Back Sikorsky S-56 / CH-37 Mojave / HR2S
1953

Sikorsky S-56

The Sikorsky S-56 came into being as an assault transport for the U.S. Marine Corps, although some 60 per cent of those eventually built were to meet U.S. Army orders. The original requirement was for an assault transport helicopter capable of air-lifting 26 troops and their equipment. The S-56 was Sikorsky's first twin-engined helicopter, although the traditional single main rotor layout was retained, this being a 5-blade unit designed to be able to sustain the aircraft in flight with one blade shot away. For several years the S-56 was the western world's largest and fastest military helicopter, and held two height-with-payload records from 1956-59. It was also the first production helicopter to have a retractable main undercarriage, this being housed at the extremities of the small stub wings in the pods containing the engines. Loading of the aircraft was via clamshell nose doors, giving access beneath the flight deck to the 53.80m3 cabin in a similar manner to the fixed-wing Bristol 170 Freighter. A winch capable of hoisting 907kg at a time was fitted in the cabin roof to assist the loading of cargo.

The U.S. Navy placed an order in May 1951 for a prototype XHR2S-1, which was flown for the first time on 18 December 1953. The first of sixty HR2S-1's was flown on 25 October 1955, deliveries to Marine Corps Squadron HMX-1 starting in July 1956. A small batch of these aircraft were modified as HR2S-1W patrol aircraft with a huge AN/APS-20E search radar under the nose and additional crew members for radar picket duties. In 1954 an HR2S-1, redesignated YH-37, was evaluated by the U.S. Army, from which followed orders for ninety-four similar aircraft as H-37A Mojave for general transport duties.

Production of the S-56 ended in May 1960, but Sikorsky were engaged until the end of 1962 in converting all but four of the H-37A's to H-37B (later CH-37B) standard. Improvements in this version included the installation of Lear auto-stabilisation equipment and the ability to load and unload while the helicopter was hovering. The Navy and Marine S-56's became CH-37C's under the 1962 designation system. Some later production S-56's had 2100hp R-2800-54 engines.

The S-56's rotor and transmission systems were utilised in the development of the abortive Westland Westminster and Sikorsky's own S-60 and S-64 crane helicopters, but hopes of selling the S-56 on the commercial market were not realised, due mainly to the high operating costs of a piston-engined machine of this size, and a proposal to fit Lycoming T55 gas turbines was not adopted.

K.Munson "Helicopters And Other Rotorcraft Since 1907", 1968

Sikorsky S-56 / CH-37 Mojave / HR2S

Immediately after the S-55 had entered production, Sikorsky began working on the design of a larger helicopter, intended as an assault transport for the Marines. A twin-engine solution was chosen, and to save cabin space, it was decided to house the two large radial engines in outboard nacelles, from which two drive shafts linked up directly with the reduction gear assembly which drove the big five-blade metal rotor. The large cargo bay had a hoist capable of lifting a one tonne load. The main landing gear wheels retracted, but the tailwheel was fixed.

Some of the 60 aircraft ordered by the Marine Corps were converted into radar patrol craft (military designation HR2S-1W), with a bulbous dielectric radome under the nose, but this transformation was unsuccessful. The Army ordered 91 aircraft, designated H-37A "Mojave".

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

Sikorsky S-56 / CH-37 Mojave / HR2S

Sikorsky originally developed the Model S-56 twin-engined heavy lift helicopter in response to a 1950 Marine Corps requirement for an assault transport able to carry twenty-three fully equipped troops. In 1951 the Navy ordered four XHR2S-1 prototypes for USMC evaluation, and the first of these made its maiden flight in December 1953. In 1954 the Army borrowed one of these preproduction machines, designated it the YH-37, and subjected it to rigorous operational and maintenance evaluations before returning it to the Marines. On the basis of the large helicopter's excellent showing during the Army evaluation, Sikorsky was in late 1954 awarded a contract for nine production H-37A Mojaves. The first of these reached Fort Rucker during the summer of 1956, at about the same time the HR2S-1 naval variant was entering regular Marine squadron service. The Army subsequently placed orders for a further 85 H-37As, and all ninety-four aircraft were delivered by June of 1960.

At the time of its introduction into the Army inventory the H-37A was the largest helicopter in U.S. military service. It was also Sikorsky's first multi-engined helicopter, and in developing it the company chose to break with then-current industry practice by using a single five-bladed main rotor instead of two fore- and aft-mounted tandem rotors. The Mojave's designers chose not to locate the aircraft's engines in the upper section of the fuselage, as was common with most other contemporary heavy lift helicopters, but instead placed the 1900hp Pratt & Whitney radials in nacelles fixed to the ends of short shoulder-mounted stub wings; the engine nacelles also accommodated the machine's fully retractable, twin-wheeled main landing gear legs. The H-37's innovative engine arrangement gave the craft an unobstructed cargo bay of nearly 1500 cubic feet, large enough to carry three Jeeps, twenty-four stretchers, or up to twenty-six fully-equipped troops. The Mojave's nose section was equipped with large clam-shell doors which allowed vehicles to be driven straight into the cargo area, with the cockpit placed above and slightly to the rear of the doors to ensure good visibility forward and to the sides. The H-37's tailboom was very similar in appearance to that of the H-34, in that it sloped downward toward the tailwheel and ended in a sharply upswept vertical tail unit carrying a four-bladed anti-torque rotor.

In 1961 Sikorsky began converting the Army's H-37As to -B model standard by installing automatic flight stabilization systems, crash-resistant fuel cells and modified nose doors. All but four -A model aircraft were eventually converted; in 1962 these were redesignated CH-37A, while the modified machines became CH-37B. Records indicate that the Army also evaluated one of the Navy's two radar-equipped HR2S-1W airborne early warning (AEW) aircraft. This machine (BuNo 141646) retained the AEW variant's large chin-mounted radome and AN/APS-20E search radar, and was operated in Army markings and two-tone 'Arctic' paint scheme.

The CH-37 was developed just prior to the widespread adoption of the turbine engine as a standard helicopter powerplant and, as a result, the type was forced to rely on larger, heavier and less powerful pistons. This did not prove to be an insuperable handicap, however, for the Mojave ultimately proved to be a more than capable heavy lifter when properly employed. Perhaps the best illustration of such employment occurred in Southeast Asia during the summer and fall of 1963. In June of that year four CH-37Bs were temporarily deployed to Vietnam to assist in the recovery of downed U.S. aircraft. By the following December the Mojaves had recovered an estimated $7.5 million worth of equipment, most of which was sling-lifted out of enemy-dominated areas virtually inaccessible by any other means. That the CH-37 did not see more extensive service in Vietnam is primarily the result of its replacement in the Army inventory by the turbine-powered Sikorsky CH-54 Tarhe, a machine that weighed slightly less than the CH-37 but which could carry nearly four times as many troops or five times as much cargo. The last CH-37 was withdrawn from Army service in the late 1960s.

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

Sikorsky S-56 / CH-37 Mojave / HR2S

Developed to meet a US Marine Corps requirement for a large assault helicopter to carry 26 troops or military vehicles, for which clamshell nose-opening doors were provided, the Sikorsky S-56 was the first Sikorsky twin-engined helicopter. Two 1417kW Pratt & Whitney R-2800-50 Double Wasp engines (1566kW R-280054s on late production aircraft) were mounted on stub wings, and the nacelles also housed the main legs of the retractable landing gear, the first application of this feature in a production helicopter. The prototype XHR2S-1 flew on 18 December 1953 and 60 production machines were delivered from July 1956. Two HR2S-1W . helicopters were converted for US Navy early warning operations with AN/APS-20E radar under the nose. US Army evaluation of an HR2S-1, under the designation YH-37, resulted in orders for 94 H-37A Mojave helicopters which went into service, initially with 4th Medium Helicopter Transportation Company, in February 1958. Modernised H-37As redesignated H-37B (later CH-37B), were redelivered to the US Army from 1961.

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

FACTS AND FIGURES

- Mojaves were replaced by the CH-54 Tarhe, which weighed less but could lift five times as much cargo as the CH-37.

- In all, 150 S-56s were built; a prototype, 55 for the USMC and 94 for the Army.

- 1959 saw the first overseas H-37 deployment, by the Army to Germany.

- Army H-37As entered service with the 4th Medium Helicopter Transportation Company in February 1958.

- The H-37A had a fuselage capacity large enough to hold three Army jeeps.

- The Army briefly evaluated one of the two HR2S-1Ws in 'Arctic' colours.


Photo Gallery 

An Army H-37 sits in the Arizona desert with its clamshell nose doors open and a jeep 4x4 light truck driving out. The Marines were able to operate these relatively large aircraft from helicopter carriers as well as from shore bases and in the field.

A U.S. Marine Corps HR2S-1 twin-engine helicopter lifts an experimental automatic artillery weapon weighing 3,000 pounds. Twin external drop tanks are also fitted. This was Sikorsky's first helicopter with twin engines, which, mounted externally, allowed for maximum internal cargo space.

Sikorsky S-56

Technical data for S-56

Engine: 2 x Pratt & WHitney R-2800-54 turboshaft, rated at 1565kW, main rotor diameter: 21.95m, fuselage length: 26.80m, height: 6.71m, take-off weight: 14074kg, empty weight: 9457kg, max speed: 209km/h, service ceiling: 2652m, range: 235km

Comments1-20 21-40 41-60 61-80 81-100
Tony Soares, e-mail, 31.01.2011reply

I was with the 90th Aviation Company in Germany from Nov 1966 to April 1969. It was located in Illeshein and later moved to Hanau in 1968. I was a crew chief then flight engineer on "615". Another member of the unit, Jim Pimental, posted above and I remember pilot Clarence Gatewood, Donald Gatewoods father who posted above also. I might even have some old orders with Gatewood on them. Any others from the unit please contact me. tony_is@msn.com

francis j oconnor, e-mail, 20.03.2011reply

I served with the 90th transportation co. from 1961 to 1964 in Illeshiem germany willy permansu was the company cleark Billy mynahan was in the motor pool sargant bantugun was the 1st sargent they called me shorty if anyone remembers contact me at oconnor237@live.com

A. Wayne Ward, e-mail, 11.05.2011reply

Seems I should call most of you guys 'whippersnappers' except we share some unique experiences tho years apart. I piloted HUS (261)and HR2S (461)in '56-'60 at New River. Remember the night training and carrier exploits? Although no combat service one recalls flying the HUS and HR2S with Aircraft Carriers as base with certain memories of feeling one had just been through a war each at-sea ops!

lxbfYeaa, e-mail, 14.03.2024 A. Wayne Ward

20

reply

RBONCZEWSKI, e-mail, 09.07.2011reply

need an s-56 pylon for restoration of a s-60 skycrane. it will be a static display in a museum. thankyou!

ron hodges, e-mail, 26.07.2011reply

I was in the 19th trans co at camp humphrey,s. korea and was with them in vietnam in 1963-64.And returned to korea with the 19th.

Walter Kern(Zych), e-mail, 04.09.2011reply

During the time, 1962 thru 1964, that I was in the 90th, Master Sargent Beneford M. Rushing, was the first sargent. Before I left, he was promoted to Sargent Major.

Bill Peukert bpeukert@gmail.com, e-mail, 28.09.2011reply

Went through Rucker in the spring /summer 62 then Ft. Riley, 47th trans. then Ft. Benning. 188th Transport Hel Co. attached to 1st Air Calv. Most of the Grads from Rucker stayed together though at least 1 /2 went to OCS or WO school. Most of the time was spent w new pilots or in the field in S.C. and Ft. Stewert GA. Squirrel hunting production droppe and wound up with hearing aid. Love to touch base with a great bunch of guys.....b

Joseph L. Mills, e-mail, 01.12.2011reply

30 November 2011 - I grew up on the CH-37. I served with the CH-37's from Mar 1959 early 1965. I was age 17 when I joined the 152nd Trans Detachnment (H-37 Maint Det for the 4th Trans Co.) at Ft. Benning, GA in March 1959. Deployed to Hanau Germany in July 1959 with the unit. Returned to the U.S. and joined the CH-37 unit (47th Trans /329th Maint Det)at Ft. Riley, Kansas in Nov 1962. The unit moved to Ft. Benning in Mar 63 and was assigned to 10th Air Tranport Bde, supporting the 11th Air Assault Div (Test). The unit was redesignated as the 188th Trans or Hel Co? The CH-37's were reassigned and replaced with the Chinooks. The Mojave helped to pioneer Army Aviation and Air Mobility as we know it today. It was a great helicopter in its day! I retired after 21.5 years of service in Army Aviation in 1980.

The 4th Trans Co (CH-37) and 152d Tran Det has been having an annual reunion since about 1990. Anyone who served in the 4th or 152nd is welcome to join. If interested, contact me an my email address josephmills@centurytel.net

Douglas H Muenzhuber, e-mail, 05.01.2012reply

I was with the 90 trans co.in Illeshiem Germany from 1963 to 1965 when I went to fort benning Ga to the 610th. I was schooled on the chinook & went to veitnam with the unit.
Glad to see some 90 guys out there. I remember 1st sargent Bantugan. My platoon sargent was sgt shaw. Give me a line anytime.

Jerry Ogles, e-mail, 27.06.2013reply

I, too, was checked out on the CH 37 at Ft. Rucker, graduating from the transition course April 11, 1968. Was assigned to Camp Humphreys, Korea with the 19th Avn Co from June 1968 to February 1970. I was involved in flying the last CH-387's out of Korea to Tokyo Bay in 1969. CW2 Brian Arsenault, a neighbor today, flew the last CH 37 out of Korea, and I was the last CH 37 pilot left in the unit. I have a plaque to prove it. (*__~)

Jim Boyle, e-mail, 13.11.2013reply

I was stationed at Nelligen from Jan 70 to 71. 10th Avn Co. We had about 4 37's but only one was usually flyable. Most of our time was penciled in at the time. Chinooks were on the way over and they replaced the aging 37's. Jim Reynolds was the chief pilot and flew most of the nuclear warhead replacement missions. VietNam was in winddown and Warrant officers like me were offered and early release. I took and early out but have often wonderd what staying on and flying Chinooks would have wrought.






cements. We put my V.W. thru the clam shells so we'd have a car at the Canadian fly-in.

Jim Boyle, e-mail, 13.11.2013reply

I was stationed at Nelligen from Jan 70 to 71. 10th Avn Co. We had about 4 37's but only one was usually flyable. Most of our time was penciled in at the time. Chinooks were on the way over and they replaced the aging 37's. Jim Reynolds was the chief pilot and flew most of the nuclear warhead replacement missions. VietNam was in winddown and Warrant officers like me were offered and early release. I took and early out but have often wonderd what staying on and flying Chinooks would have wrought.






cements. We put my V.W. thru the clam shells so we'd have a car at the Canadian fly-in.

Anthony Gargani, e-mail, 26.02.2012reply

The HR2S-1 (We called it the Cross Eye) was used to take us from Cherry Point to Bomb Target 11 in 1960 to 1962 when we had to take boats, motors and fuel. It was good duty. Sargeant Bill Baucom was the greatest. The Cross Eye was a fun ride. Some of my Buddies were: Sgt Ray (Distinguished Life Expert Team Shooter) who helped us with M-1 trigger housing groups to improve our marksmanship. Sgt Baucom let us shoot all day when we could get the ammo. Cpl Gates, Cpl Victor G Vanous, Fred Davis, Hollis, Fuzullo seem to be the only guys I remember. As I said IT WAS GOOD DUTY: Hunting,fishing, wild ponies and all. Semper Fi.

Bill Davenport, e-mail, 29.06.2012reply

I served in Santa Ana Ca. 1957-58-59 with hmr462, we had about 20 planes of the S-56 , flew them across county from Conn. An old man now but that was a good time to look back on.

Dan DeStefano, e-mail, 08.07.2012reply

To Donald Gatewood: Star Elton & I were pilots in 90th from Nov 67 to Dec 68. We both flew with your dad "Cal" and deeply admired him, along with Paul Shaw, and John Banks. They were in my opinion, icons of Army Aviation. I met my wife Susan in Hanau, who worked as a hostess for the service club at Fliegerhost. I remember having dinner at your house, where your mom made Mexican food that was so good, it would make you cry.

Of all the aircraft I piloted in the Army, the Mojave was my favorite. Your dad & I would sneak my VW beetle into the cargo compartment so that we'd have a way for the crew to get to a town nearby town for a better room and food than the local Army base. I last spoke to Cal by phone around 2000. He was the best.

Dan DeStefano

Bob Dashiell, e-mail, 09.07.2013reply

I too flew crew chief /Gunner on 998 out of natrang 1964 /65

Glen Price, e-mail, 09.06.2014reply

I was in the 90th Aviation Company from 1967 to 1968. I was station in Illesheim Germany, help get all CH37 Mojaves out of mothball storage and make ready to fly and we the 90th Avn. Co. moved to Hanau. I had to work in my class A uniform because that was all I had, my first tour was Vietnam, B Co.1st. Avn. Bn. 1st.INFANTY DIVISION.I was a crewchief I remember Tony Soares, Dan DeStefano drove VW inside and I straping it down for the last time, after that we could only haul military jeep on missioms. I also was company amateur photographer for a very short time.

Bob Cox, e-mail, 22.06.2014reply

Would anyone have known my father Thomas C. (Kip) Cox?
He died with his mother in a car crash ten years ago and I've found done things recently he never spoke of.
He apparently flew " extraction detail"- based out of El Toro, overseas Marble Mountain in '66.
You guys are my heroes!

Pete Zielenski, e-mail, 07.06.2010reply

I was serving as a FA advisor to the Vietnamese in June 1965. We used the CH37 to internally load and move two stripped down 105 MM howitzers into Dong Xoai to replace two that were damaged during the battle of Dong Xaoi. As I recall I heard that one of those two blew an engine after
off loading the weapons. I remained on the ground with the weapons. Checkout the new book "Dong Xoai Vietnam 1965" by Joe Kubert. Amazon has the book. The book doesn't ref the move but I was there.

nike air max 90, e-mail, 09.07.2010reply

There are multifarious Nike Air Max 90 shoes are available for you now. Nike Air Max 90 shoes are sold so well on iofferitems.com.The best and cheapest nike shoes sell on iofferitems.com.They are absolutely needed because of their comfortable and smart.And these Nike Air Max 90 shoes sneakers are the perfect partner for your favorite jeans.The best and cheapest nike shoes sell on iofferitems.com.

1-20 21-40 41-60 61-80 81-100

Do you have any comments ?

Name   E-mail


Virtual Aircraft Museum


All the World's Rotorcraft


Back AVIATION TOP 100 - www.avitop.com Avitop.com