CH-54 Skycrane / Tarhe
The Sikorsky (model S-64A) CH-54A/CH-54B "Skycrane", with a crew of three, was designed for heavy internal or external lift of heavy bulk loads. This helicopter was used to lift very heavy objects. It can pick up and move a small house. It can lift large, heavy pipes. It can carry a train engine or even another helicopter. It can be used to build buildings. The helicopter can lift a big, heavy object. The helicopter carries it through the sky. The helicopter can set it down many miles away.
A hoist was provided to allow pickups and deliveries without landing. A lightweight van (universal pod) could be attached to the fuselage for use as a mobile command post, maintenance and repair shop, or as a Mobile Army Surgical Hospital (MASH). The field hospital was equipped with X-Ray, lab equipment, and blood bank. It was well lighted and air conditioned so surgery could be performed where ever it was needed. A "people pod" was designed to carry 45 combat-ready troops.
The T-54A Tarhe had a six-bladed main rotor, four-bladed metal tail rotor, was powered by two Pratt & Whitney T73-P-1 4500 shp turbine engines, and had a speed of 128 mph (111 knots). The CH-54B was powered by two Pratt & Whitney T73-P-700 4800 sph turbine engines. Sikorsky designed a twin-engined lifting rotor system, with standard cockpit forward and a vestigial cockpit below and facing aft. This rear-facing pilot's seat to provide a clear view of the cargo. That latter position was used when the helicopter is lifting a large load; the direct observation of the hoisting process by the pilot makes for better coordination. To the lifting rotor the designers added widespread landing gear that could straddle large loads for easier pickup. Consequently, the various versions of the S-64 can handle individual cargos or special vans with equal ease.
The S-64 all purpose transport helicopter, also known as the flying crane, combined the maneuverability and vertical lift characteristics of the helicopter with a new concept-detachable pods. These pods, tailored to meet the requirements of a tactical mission, are attached to the underside of the S-64. The series of pods designed for the S-64 include a troop carrier, which holds up to 60 troops, and a cargo carrier. Without the pod, the S-64 can transport missiles and missile launchers, such as Honest John and Little John. In addition, the flying crane has a tow capability which provides a helping hand to disabled vehicles. The characteristics of the S-64 helicopter, designed by the Sikorsky Aircraft Company, include a 2-man crew, accommodations for 3 passengers, a gross weight of 38,000 pounds, and a maximum range of 600 nautical miles with two engine cruise and 800 nautical miles with one engine cruise.
Except for helicopters like the Sikorsky Skycrane that is designed especially for sling work, most helicopters have the attachment for external loads well below the center of gravity. Thus they can be inadvertently driven into the ground if the pilot tries to free the load by doing anything but pulling vertically.
Based on the previous records of utilizing military and commercial helicopters to transport external loads over terrain obstacles, it was recognized that a vehicle designed to accomplish this task more efficiently would be a requirement in the near future. Accordingly, Sikorsky Aircraft initiated design of the first prototype Flying Crane in 1958. Sikorsky's first 'flying crane' helicopter was the Sikorsky S-60, developed from the S-56 / H-37 and retaining that machine's powerplant, transmission and rotor system. 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. 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. The S-60 was used for a number of years, improving the concept of a heavy lift, external load, VTOL aircraft.
The S-60 utilized reciprocating engines. In order to obtain a more efficient vehicle for field operations, the S-64 turbine powered Flying Crane was initiated in 1959. The total IR&D funds associated with both of these efforts, excluding any engine development costs, amounted to over $11, 000, 000. During the past three years this airframe and equipment development !R&D funding amounted to over $1, 000, 000. Because of these efforts, it was possible to provide developed Flying Cranes for US Army use when the need arose.
Earlier Sikorsky designs contributed to the development of the S-64. The six-bladed rotor system came essentially intact from the twin-engined S-56. Much design and flight experience came from the S-60 program, the predecessor flying crane powered by piston engines. The original specification was developed by the Army of the Federal Republic of Germany for a heavy-lift helicopter capable of hauling ten tons vertically. Deliveries have been made to the German Army, and to the US Army. The US Army bought 97 with deliveries between June, 1964 and 1972. In a comparison based on similar funded aircraft development programs, it is estimated that the development of the S-64 Flying Crane would have cost approximately thirty to forty million dollars. Through the above company-funded IR&D austerity program, this effort was accomplished for less than $1Z million, thereby providing the developed vehicle for about one-third of the normal costs. An appreciable time savings was also accomplished by this company-sponsored development in advance of the military requirement. This permitted the S- 64 (YCH-54A) Flying Cranes to be delivered to the combat zone when needed in 1965. Had this program been initiated when the need arose for this aircraft in Viet Nam in 1965, it is estimated that a 3-year delay would have resulted in development of this aircraft toward fulfillment of the military's requirements.
The company sponsored IR&D development of the S-64 Flying Crane led to achievement of the largest heavy lift helicopter in the free world. Many technical advances inherent in the development of this large-scale helicopter were achieved. The technology advancement achieved on the S-64 Flying Crane development allowed a more rapid transition to the current CH-53A assault helicopter presently in production. As a result of very successful operation, the equipment developed through the IR&D sponsored 5-64 program has been ordered in large production quantities by the U.S. Army.
In early 1969 the US Army awarded a new contract to Sikorsky Aircraft to make several improvements on the CH-54 Flying Crane. The most notable change in the aircraft is an increased payload of 25,000 pounds. This is an increase of 5,000 pounds over the original. This modification also would increase the gross weight of the Crane from 42,000 pounds to 47,000 pounds. In addition, the contract called for improvements in altitude performance, hot weather operating capabilities, and the dynamic components. The new version of the Flying Crane was designated the S-64F.
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