C-17 Globemaster III Airlifter

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The U.S. Air Force C-17 Globemaster III airlifter is designed to fulfill global airlift needs for many years. It can carry large combat equipment and troops or humanitarian aid directly to small austere airfields anywhere in the world. Vought is the largest structures subcontractor to Boeing on the C-17, performing work at sites in Dallas, Texas, Milledgeville, Ga., and Brea, Calif.

In the Field

The C-17 program began in 1983, making its maiden flight on Sept. 15, 1991. The Air Force declared the first C-17 squadron operational in January 1995. Since then the fleet has amassed more than a million hours of flight. The milestone is the equivalent of one of the cargo jets flying every minute of every day continuously for more than 114 years.

The C-17 has flown a litany of missions in its brief history, including natural disaster relief for earthquakes, hurricanes Katrina and Rita, the 2004 Indian Ocean tsunami, and war missions that included an unprecedented formation of 15 C-17s that dropped more than 1,000 troops into northern Iraq during the first days of the Iraq conflict. This was the first combat insertion of paratroopers using a C-17.

The C-17 set 13 world records during flight testing in November 2001 at Edwards Air Force Base, including resetting two of the 22 world records that it claimed during initial flight testing in 1992-1994. Eleven of the records were for maximum altitude with various payloads as the C-17 carried payloads up to 40,000 kg (88,200 pounds) to an altitude in excess of 43,800 feet. The other records were for maximum altitude in horizontal flight without a payload, and greatest payload to a height of 2,000 meters.

In May 1995, Boeing and the C-17 received the prestigious Robert J. Collier Trophy from the National Aeronautic Association as the top aeronautical achievement in the United States for 1994.

U.S. Air Force Contracts

On May 31,1996, Boeing and the Air Force signed a seven-year $14.2 billion contract to build the next 80 C-17s, starting in 1997, with final deliveries in 2004. With the 40 aircraft previously on contract, the additional buy brought the Air Force C-17 fleet to 120. Follow-on procurement contracts since then include 60 more aircraft (in 2002) and 22 (in 2007), bringing the C-17 fleet total to 202 by late 2009.

Capabilities

The C-17 is a high-wing, four-engine, T-tailed aircraft with a rear-loading ramp. The aircraft is 174 feet long, 55.08 feet high and has a wingspan of 169.75 feet. Maximum payload is 170,000 pounds (about twice that of a C-141B).

With a payload of 160,000 pounds, the C-17 can take off from a runway of 7,600 feet, fly 2,400 nautical miles, and land on a small austere airfield in 3,000 feet or less. Ferry range of the C-17, which also can be refueled in flight, is 4,700 nautical miles. The four engines are Pratt & Whitney PW2040 series turbofans, designated by the Air Force as the F117-PW-100. Each engine produces 40,440 pounds of thrust, located on pylons ahead of and below the wing leading edge. The engines are equipped with directed-flow thrust reversers capable of deployment in flight. On the ground, a fully loaded aircraft, using engine reversers, can back up a 2 percent slope.

Two of the nacelle design features account for the C-17's capability to make extreme short-field landings at heavy gross weights: propulsive lift technology and an advanced thrust reverser design. Propulsive lift results from directing engine exhaust across both sides of the flap. Combined with the advanced thrust reversers, propulsive lift enables short landings. The thrust reversers are an integral part of the C-17 nacelle. When thrust reversal is initiated, both fan and core exhausts are redirected. Thrust is directed forward and upward through exposed louvers for maximum reverse thrust. During ground operations, the thrust reversers can be deployed with engines idling, directing engine blast away from personnel working cargo.

A cockpit crew of two, plus one loadmaster, operates the C-17, a cost-effective flight crew complement made possible through advanced digital avionics. The system uses four cathode-ray tube displays, two full-capability HUDs (Head-Up Displays) and advanced cargo systems.

Cargo is loaded onto the C-17 through a large aft door that can accommodate military vehicles and palletized cargo. The C-17 can carry and airdrop 102 paratroopers and virtually all of the Army's outsized combat equipment.

Vought’s Role

As the largest subcontractor on the C-17 program, Vought delivers 23,700 pounds of structure every 16 manufacturing days. Vought fabricates and assembles the engine nacelles, accessory doors, vertical and horizontal stabilizers, the rudders and elevators, ailerons, and the universal aerial refueling receptacle slipway installation (UARRSI). The company’s work on the C-17 tail sections and engine nacelles includes systems integration and engine build-up.

The nacelles, built of aluminum, titanium, high-strength steel and epoxy and polyimide composites, contain 2,405 parts. Each nacelle is 8 feet, 9 inches in diameter and 22 feet long.

Vought-built vertical stabilizers are 48 feet long and 13 feet wide, while the horizontal stabilizers measure 65 feet from end to end – larger than the wings on a typical fighter aircraft. Each horizontal stabilizer is 23 feet wide. The tail section contains 7,191 parts and 144,575 fasteners.

The company also produces the composite ailerons, elevators and rudders for the C-17 -- 10 assemblies per shipset, weighing 2,650 pounds. Each assembly is 15 to 21 feet long.

Vought also produces the upper forward fuselage panel assembly, which includes the UARRSI and crew escape door. The UARRSI allows the C-17 to receive fuel in flight from Air Force KC-10s and KC-135s, adding to the C-17’s range and mission effectiveness. The UARRSI is more than 11 feet wide and 19 feet long.

With the 2003 acquisition of The Aerostructures Corp., Vought provides the C-17 internal wing structure as well. The company’s facility in Brea, Calif., produces the wing spar webs, spar caps and stringers.

Vought’s Manufacturing Technologies and Initiatives

Vought’s C-17 parts production employs high﷓temperature carbon polyimides, placing the company on the leading edge of composites technology. Weight savings, combined with strength and the ability of the composite material to withstand extreme heat, make their use on the C-17 a superior alternative to conventional materials.

Another innovation developed for C-17 manufacturing was the design of an automatic fastener adapted to the complex circular shapes of the nacelle. The resulting nacelle autoriveter has a one-of-a-kind capability to manufacture parts for the aircraft. A unique part-handling and positioning system is a key to the system’s success. A five-axis semirobotic part positioner with laser sensors automatically locates the part for riveting. The sensors send data to the control system that automatically levels the parts.

The company's automated machining centers, Flexible Machining Cell (FMC) and Integrated Machining System (IMS) produce quality machined parts with up to a 3-to-1 improvement in productivity over conventional machining. These centers produce more than 250 parts for the C-17. In addition, Vought has installed a new High Speed Machining Center, equipped with machines that cut with speeds in excess of 18,000 rpm, producing parts with a 6-to-1 improvement over conventional machining.

Under a separate contract with the U.S. Air Force, Boeing and Vought redesigned, tooled, manufactured and assembled a lower-cost engine nacelle and thrust reverser for the C-17. The new nacelle concept was designed entirely using three-dimensional (3-D) computer models at Boeing’s Long Beach facility. It was directly transferred to Dallas for use in design of tools, and for electronic transfer to the machining center -- a virtual “art-to-part” manufacturing process. This new nacelle resulted in significant cost savings to the Air Force since 1997 production.

Vought worked with Boeing on a redesigned horizontal tail using a new graphite horizontal stabilizer that replaced the previous aluminum structure. The first C-17 Globemaster III with the composite horizontal stabilizer -- installed on aircraft number P-51 -- was delivered to the Air Force July 30, 1999. All C-17s from that point forward are equipped with the new composite tail. It has 2,000 fewer parts and 42,000 fewer fasteners than the aluminum unit and it weighs 470 pounds less.

Vought Milestones

In July 1997, Boeing and Vought signed a memorandum of agreement -- valued at $1.9 billion -- for production of major components for 80 additional C-17s over a six-year period. The agreement covers fiscal years 1997-2002 with deliveries continuing into early 2004.

In March 2002, Boeing and Vought signed another agreement to produce components for 60 additional C-17 aircraft. The contracts for follow-on aircraft, including the 22 additional aircraft in the fiscal year 2007 U.S. Department of Defense budget, will extend C-17 manufacturing at the Dallas and Milledgeville facilities through most of 2009.

In 2002, Vought celebrated delivery of its 100th shipset for the C-17. The finished aircraft rolled out of its hangar in Long Beach, Calif., in October and was delivered to the U.S. Air Force.