Information
The 777 is Boeing's 2nd newest airplane type, designed to fill the size gap between the 767 and 747. It is the world's largest twinjet.The average number of passengers ranges from 305 to 328 passengers in three classes. The first 777-200, was first delivered in May 1995, has a range of up to 5,680 miles. An new version, the 777-200IGW, can carry passengers 8,320 miles. This version was first delivered in early 1997. The 777 provides the most payload and range capability and growth potential in the medium-size aircraft category.
New 777 designs
Boeing is now developing a new version of the 777 to carry 368 to 394 passengers in three classes, up to 6,200 miles. The company is also working on a derivatives of the 777-200 and 777-300, that could fly 10,000 miles.
Intial backers
At first, United Airlines, All Nippon Airways, British Airways, Japan Airlines and Cathay Pacific, were the carriers that Boeing originally consulted on the 777. They discussed traffic loads, service frequency, etc; to provide for the carriers needs. Out of these meetings came the ideas to include prevously 'optional' equipment, such as: GPS, and satellite communications. This claims Boeing will lead to less variance in designsm which will result in a more economical package.
Wing Design
The 777 wing uses the most aerodynamically efficient airfoil ever developed for subsonic commercial aviation. In a further refinement of designs introduced on the Boeing 757 and 767, the 777 wing features a long span with increased thickness while achieving higher cruise speeds. This advanced wing enhances the airplane's ability to climb quickly and cruise at higher altitudes than competing airplanes. It also allows the airplane to carry full passenger payloads out of many high-elevation, high-temperature airfields.
Fuel volume requirements for the 777 are accommodated entirely within the wing and its structural center section. For the initial airplane, fuel capacity is 31,000 gallons (117,335 L), while the longer-range model and the 777-300 model can carry up to 45,220 gallons (171,160 L).
Airlines helping to design the 777 encouraged Boeing to commit to the performance capabilities of an optimum wing, which has a span of 199 feet 11 inches (60.9 m).
Propulsion
The 777 engines are as quiet as a 767 engines, but provide 40 percent more power. Key factors in this performance are new, larger-diameter fans with wide-chord fan blade designs and bypass ratios ranging from 6-to-1 to as high as 9-to-1. This compares to the typical 5-to-1 ratio for the engines of today's widebody jets. The engines themselves are comparable to the fuselage of a 737 in width.
The three leading engine manufacturers have developed more efficient and quieter turbofans to power the 777, and all three have been selected by 777 customers. For the initial airplane, these engines are rated in the 74,000- to 77,000-pound thrust class. For the longer-range model and the 777-300, these engines will be capable of thrust ratings in the 84,000- to 98,000-pound category. The engines could be developed to even higher thrust ratings, depending on future payload and range requirements.
Materials
New, lightweight, cost-effective structural materials are used in several 777 applications. For example, an improved aluminum alloy is used in the upper wing skin and stringers. Known as 7055, this alloy offers greater compression strength than current alloys, enabling designers to save weight and also improve corrosion and fatigue resistance.
Progress in the development and fabrication of weight-saving advanced composite materials is evident in the 777. Carbon fibers embedded in recently available toughened resins are found in the vertical and horizontal tails. The floor beams of the passenger cabin also are made of these advanced composite materials.
Flight Deck and Airplane Systems
In response to airline preference expressed during the pre-launch definition phase, the layout of the 777 flight deck is in a horizontal format similar to that of the 747-400. Principal flight, navigation and engine information is presented on six large display screens. Although these displays resemble conventional cathode ray tube (CRT) screens, they incorporate advanced liquid-crystal display technology. The depth of the new "flat panel displays" are about half that of CRTs. In addition to saving space, the new displays weigh less and require less power. They also generate less heat, which contributes to greater reliability and a longer service life. Another benefit: they do not require the heavy, complex air conditioning apparatus needed to cool equipment on current flight decks. Pilots appreciate that flat panel displays remain clearly visible in all conditions, even direct sunlight.
Interior
In addition to being one of the most spacious passenger cabins ever developed, the 777 interior offers operators unsurpassed configuration flexibility. Flexibility zones have been designed into the cabin areas specified by the airlines, primarily at the airplane's doors. In one-inch increments, galleys and lavatories can be positioned anywhere within these zones, which are pre-engineered to accommodate wiring, plumbing and attachment fixtures. Passenger service units and overhead stowage compartments are designed for quick removal without disturbing ceiling panels, air conditioning ducts or support structure. A typical 777 configuration change is expected to take as little as 72 hours, while such a change might take two to three weeks on existing aircraft.
Large overhead compartments provide passengers with increased stowage capacity. Outboard as well as center stowage units are designed to open downward for convenient loading. When closed, they fit neatly into the streamlined contours of the interior architecture and allow ample overhead clearance.
For improved, more efficient in-flight service, the 777 is equipped with an advanced cabin management system. Linked to a computerized control console, the cabin management system assists cabin crews with many tasks and allows airlines to provide new services for passengers, including a digital sound system comparable to the most state-of-the-art home stereo or compact disc players.
Cargo Capacity
The fuselage cross-section of the 777 is circular and large enough to accommodate not only a spacious passenger cabin, but excellent capacity in the lower hold. The lower hold mechanized cargo handling system is compatible with all unit load devices (ULD) and pallets. One of the container arrangements utilizes LD-3s loaded side by side. The 777-200 can accommodate a maximum of 32 LD-3 containers plus 600 cubic feet (17 cubic meters) of bulk-loaded cargo for total lower hold volume of 5,656 cubic feet (160.17 cubic meters). The 777-300 can accommodate a maximum of 44 LD-3 containers plus the same amount of bulk-loaded cargo as the -200 model for a total lower hold volume of 7,552 cubic feet (214 cubic meters).
Landing Gear
The main landing gear for the 777 is in a standard two-post arrangement but features six-wheel trucks, instead of the conventional four-wheel units. This provides the main landing gear with a total of 12 wheels for better weight distribution on runways and taxi areas, and avoids the need for a supplemental two-wheel gear under the center of the fuselage. Another advantage is that the six-wheel trucks allow for a more economical brake design. The 777 landing gear is the largest ever incorporated into a commercial airplane.
777 - Aircraft Profiles - Aviation Resource Center
