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Military

CHAPTER 1

INTERNAL CARGO-CARRYING HELICOPTERS

1-1. INTRODUCTION. This chapter identifies the Army helicopters used for carrying internal loads. It also describes the capacities, capabilities, and limitations of these helicopters.

1-2. UTILITY HELICOPTERS. A utility helicopter is a general-purpose aircraft that has limited carrying capability. Its mission includes transporting troops, cargo, or patients. Two helicopters fall into this type: the Iroquois and the Blackhawk.

a. The UH-1 (Iroquois) is a single-turbine-engine, single-rotor helicopter with a skid-type landing gear (Figure 1-1). There are three models of the UH-1: H, M, and V. The differences among models are engine horsepower, rotor size, and cargo compartment size and configurations.

(1) The UH-1 is used for aerial fire support, aerial command posts, light tactical transport, medical evacuation, and electronic surveillance.

(2) Depending on the model, the UH-1 can seat up to 11 combat-equipped troops. The cargo compartment floor has a maximum load limit of 100 psf. The cargo area contains about 220 cubic feet of obstruction-free cargo load space.

(3) The tie-down rings in the floor have a rated capacity of 1,250 pounds in the vertical and 500 pounds in the horizontal direction. Figure 1-2 shows the tie-down rings, and Figure 1-3 shows the UH-1 cargo compartment dimensions. Figure 1-4 shows a typical cargo load for the UH-1.

(4) The loading crew assembles the cargo and baggage to be transported. At the time of assembly and before loading, the loading crew compiles data covering weight, dimensions, center of gravity (CG) location, and contact areas for each item.

(5) Heavier packages will be loaded first and placed in the aft section against the bulkhead for CG range purposes.

(6) Calculate the allowable load and loading distribution by determining the final CG location, staying within the allowable limits for safe operating conditions.

(7) When operating the helicopter at critical gross weights, use the exact weight of each occupant plus equipment. If weighing facilities are not available, or if the tactical situation dictates otherwise, compute loads as follows:

  • Combat-equipped soldiers: 300 pounds per individual.
  • Combat-equipped paratroopers: 350 pounds per individual.
  • Crew and passengers with no equipment: compute weight according to each individual's estimate.
  • Litter patients (including litter, splints, and so forth): 200 pounds per individual.
  • Medical attendants: 200 pounds per individual.

b. The UH-60 (Blackhawk) is a twin-turbine-engine, single-rotor helicopter with a tricycle-type landing gear (Figure 1-5). It has a four-blade main rotor system. The Army uses two models. The UH-60A has an 8,000-pound load capacity and the UH-60L has a 9,000-pound load capacity.

(1) The UH-60 is used mainly for tactical transport of troops, supplies, and equipment. It is also used for training, mobilization, medical evacuation (Figure 1-6), and development of new and improved concepts.

(2) Depending on how the seats are installed, the cargo compartment of the UH-60 can seat up to 14 combat-equipped troops (Figure 1-7). The cargo compartment floor has a maximum load limit of 300 psf. The cargo compartment dimensions are about 72 inches wide, 54-inches high, and 150 inches long (Figures 1-8 and 1-9).

(3) The tie-down rings in the floor have a rated capacity of 5,000 pounds in any direction. The cargo restraint net rings on the walls and ceiling have a rated capacity of 3,500 pounds (Figure 1-10).

(4) When operating the helicopter at critical gross weights, use the exact weight of each occupant plus equipment. If weighing facilities are not available, or if the tactical situation dictates otherwise, compute loads as follows:

  • Combat-equipped soldiers: 300 pounds per individual.
  • Combat-equipped paratroopers: 350 pounds per individual.
  • Crew and passengers with no equipment: compute weight according to each individual's estimate.

1-3. CARGO HELICOPTERS. The cargo helicopter has a much larger capacity for carrying loads than the utility helicopter. The cargo helicopter can lift heavy, oversize loads, such as artillery weapons and ammunition, vehicles, and large boxes. The two types of cargo helicopters are the Chinook and the Tarhe.

a. The CH-47 (Chinook) aircraft is a twin-turbine-engine, tandem-rotor helicopter (Figure 1-11). There are presently two models (C and D) in the inventory. They differ mainly in engine horsepower, rotor blades, and gross weight capacity.

(1) The CH-47 is used for troop movement, cargo and weapons transportation, and as an air ambulance under day, night, visual, and instrument conditions.

(2) The CH-47 has a power-up operated ramp that permits straight-in rear loading. Two auxiliary loading ramps are hinged to the aft end ramp. When the ramp is lowered, these auxiliary ramps provide flush contact between the ramp and the ground. They may be positioned to accommodate various vehicle tread widths or butted together for easier loading of bulk cargo. The fuselage design gives the helicopter a water-landing capability. A gas turbine, auxiliary power unit provides hydraulic and electric power for ground operations.

(3) The Chinook is fitted with a hydraulic winch for use in cargo loading and rescue operations. A 3,000-pound capacity winch is mounted on the floor in the right-hand forward bulkhead. The winch has 150 feet of cable and can winch up to 12,000 pounds of cargo with the aid of snatch blocks. In addition, an internal cargo-handling system with rollers can be installed in the CH-47D model cargo compartment.

(4) The cargo compartment floor rests on rubber vibration isolators. The floor has a maximum load limit of 300 psf. The treadway aft of station 160 will withstand a wheel load of 2,500 pounds. The remaining treadway area will withstand a wheel load of 1,000 pounds. When used for additional cargo space, the ramp must be positioned level with the cargo floor, and the load on the ramp must not exceed 3,000 pounds. All models have the same cargo compartment dimensions: 90 inches wide, 78 inches high, and 366 inches long (Figure 1-12). The forward door is 36 inches wide and 66 inches high. The ramp opening is 90 inches wide and 78 inches high, and ramp incline is 6.7 degrees.

(5) The eighty-three 5,000-pound capacity tie-down fitting in the cargo floor are equally spaced in five rows 20 inches apart longitudinally (Figure 1-13). The four in the ramp are in a rectangular pattern. Each 5,000-pound capacity fitting swivels freely and can resist a single maximum load of 5,000 pounds exerted along any radius of a hemisphere, the flat side of which is the surface of the floor. The fittings are hinged so that they can be seated in floor recesses when not in use.

(6) Eight 10,000-pound capacity tie-down fittings are on the cargo compartment floor. Four fittings are interposed along both outboard rows of 5,000-pound capacity fittings, spaced at intervals of 80 inches from station 240 to station 480. These fittings are installed only when necessary because they are not always used and they might be in the way. When they are to be used, the fittings are screwed into threaded receptacles at the fitting locations. When they are not being used, threaded plugs are screwed into the receptacles to prevent entrance of foreign material and to protect the thread in the receptacles.

CAUTION

The 10,000-pound capacity tie-down fittings must be screwed into the threaded receptacles to full depth to achieve their rated capacity.

(7) The ramp provides a means of quickly loading and unloading troops and cargo. It can also support portions of a cargo load that exceed the longitudinal dimensions of the cargo floor. When used for additional cargo space, the ramp must be positioned so that the ramp floor is level with the cargo floor. The weight of the cargo item resting on the ramp must not exceed 3,000 pounds or 300 psf.

(8) The cargo compartment can hold up to 33 combat-equipped troops, 24 litters, or a combination of both (Figure 1-14). When operating the helicopter at a critical gross weights, use the exact weight of each occupant plus equipment. If weighing facilities are not available, or if the tactical situation dictates otherwise, compute loads as follows:

  • Combat-equipped soliders: 300 pounds per individual.
  • Combat-equipped paratroopers: 350 pounds per individual.
  • Litter patient (including litter, splints, and so forth): 200 pounds per individual.
  • Medical attendants: 200 pounds per individual.
  • Crew and passengers with no equipment: compute weight according to each individual's estimate.

b. The CH-54 (Tarhe) is a twin-turbine-engine, single-rotor helicopter (Figure 1-15). Two models of CH-54 are used by the military: A and B. They differ mainly in their lifting capability. The B model has more engine power and has a detachable pod that gives it internal load capabilities.

(1) The CH-54 is used to transport troops, equipment, and weapons under day, night, visual, and instrument conditions.

(2) The detachable universal pod that allows internal loads is used for many operations (Figures 1-16 and 1-17). It holds up to 45 combat-equipped troops or 24 litters (Figure 1-18). When the litters are installed, there is still room for 15 seats down the middle for ambulatory patients, attendants, or troops. The pod has a reinforced tread area that will hold equipment as heavy as a 12,700-pound howitzer. The pod has no winch, so the load must be driven or pushed into the pod. The pod can be loaded on the ground and then raised up to the helicopter. Wheels on the pod allow it to be moved on the ground.

(a) Interior dimensions of the pod are 106 inches wide, 78 inches high, and 328 inches long. There are ninety-six 5,000-pound capacity tie-down rings on the floor of the pod. Pod limitation is 20,000 pounds.

(b) Design gross weight of the pod is 20,000 pounds with an empty weight of 3,020 pounds.

(c) Exterior dimensions are--

  • Length--28 feet 1 inch.
  • Width--9 feet 6 inches.
  • Height (wheels up)--7 feet 8 inches.

(d) Floor loading is 334 psf at any location. In the vehicular tread area, the maximum allowable floor loading is 1,500 psf. Cargo fittings are flush with the floor. They have a load capacity of 5,000 pounds each. The spacing of the fittings is a standard 20-inch grid pattern.

(e) The pod has a conventional four-wheel system with pneumatic tires. It may be towed up to 5 miles per hour on level ground at a maximum gross weight of 20,000 pounds. Each of the four wheels has an independent retraction and extension system manually operated by the mechanical jacks or alternate hydraulic pumps attached to each wheel gear. These permit the pod to be raised or lowered when fully loaded. This action aids unloading the pod by allowing the use of a forklift and other cargo-moving equipment. To obtain the maximum pod wheel ground clearance of 18 inches when the pod is attached to the helicopter, full retraction of the pod wheels is possible. The pod is detached from the helicopter without using winches by extending the wheel mechanism. Figure 1-19 shows the locations of the cargo restraint rings in the CH-54 pod.

WARNING

Cargo-lifting capacity will change depending on weather and fuel level of each aircraft. Do not plan an internal cargo mission without direct coordination with the supporting aviation unit.

1-4. ATTACK HELICOPTER. The AH-58D Warrior is a new concept that has been developed under the US Army Multipurpose Light Helicopter Program. It has a 2,000-pound lift capacity. It uses the cargo hook adapter taken from the civilian Ranger 206 helicopter.

a. Characteristics. The AH-58D is the smallest helicopter and has the lowest lift capacity. The standard apex will fit the cargo hook. There is no flight engineer on the aircraft.

b. Safety. The AH-58D has the same safety items to look for as the utility helicopters, such as tail rotor, skids, and wire strike kit.



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