23-08-2012, 01:42 PM
INTERNATIONAL MEDIUM-RANGE 280 SEATER PASSENGER AIRCRAFT
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INTRODUCTION
At the instant time there are different types of aircrafts with latest technology. Every year there is a great competition for making an aircraft of having higher capacity of members inside the aircraft. So here in this report, We intend to implant the differentiation among the aircrafts having sitting capacity of 250-350 members. This report gives the different aspects of specifications like wing specification, weight specification, power plant specification and performance specification. Airbus started the development of a very large airliner (termed Megaliner by Airbus in the early development stages) in the early 1990s, both to complete its own range of products and to break the dominance that Boeing had enjoyed in this market segment since the early 1970s with its 747. McDonnell Douglas pursued a similar strategy with its ultimately unsuccessful MD-12 design. As each manufacturer looked to build a successor to the 747, they knew there was room for only one new aircraft to be profitable in the 600 to 800 seat market segment. Each knew the risk of splitting such a niche market, as had been demonstrated by the simultaneous debut of the Lockheed L-1011 and the McDonnell Douglas DC-10: both planes met the market’s needs, but the market could profitably sustain only one model, eventually resulting in Lockheed's departure from the civil airliner business. In January 1993, Boeing and several companies in the Airbus consortium started a joint feasibility study of an aircraft known as the Very Large Commercial Transport (VLCT), aiming to form a partnership to share the limited market. Airplanes come in many different shapes and sizes depending on the mission of the aircraft, but all modern airplanes have certain components in common. These are the fuselage, wing, tail assembly and control surfaces, landing gear, and powerplant.
AIRFOIL SELECTION
The airfoil is the main aspect and is the heart of the airplane. The airfoils affects the cruise speed landing distance and take off, stall speed and handling qualities and aerodynamic efficiency during the all phases of flight
Aerofoil Selection is based on the factors of Geometry & definitions, design/selection, families/types, design lift coefficient, thickness/chord ratio, lift curve slope, characteristic curves.
LANDING GEAR SELECTION
In aviation, the undercarriage or landing gear is the structure (usually wheels) that supports an aircraft and allows it to move across the surface of the earth when it is not in flying. So more importance is to be given as it carries the entire load on the ground.
OVERVIEW
The design and positioning of the landing gear are determined by the unique characteristics associated with each aircraft, i.e., geometry, weight, and mission requirements. Given the weight and cg range of the aircraft, suitable configurations are identified and reviewed to determine how well they match the airframe structure, flotation, and operational requirements.
The essential features, e.g., the number and size of tires and wheels, brakes, and shock absorption mechanism, must be selected in accordance with industry and federal standards discussed in the following chapters before an aircraft design progresses past the concept formulation phase, after which it is often very difficult and expensive to change the design.
Three examples of significant changes made after the initial design include the DC-10-30, which added the third main gear to the fuselage, the Airbus A340, where the main gear center bogie increased from two to four wheels in the -400 series, and the Airbus A-300, where the wheels were spread further apart on the bogie to meet LaGuardia Airport flotation limits for US operators.
TYPES OF GEAR ARRANGEMENTS
Wheeled undercarriage comes in two types: conventional or tail dragger undercarriage, where there are two main wheels towards the front of the aircraft and a single, much smaller, wheel or skid at rear; tricycle undercarriage where there are two main wheels under the wings and a third smaller wheel in the nose. Most modern aircraft have tricycle undercarriage. Sometimes a small tail wheel or skid is added to aircraft with tricycle undercarriage arrangements.
RETRACTABLE GEAR
To decrease drag in flight some undercarriages retract into the wings and/or fuselage with wheels flush against or concealed behind doors, this is called retractable gear. It was in late 1920s and 1930s that such retractable landing gear became common. This type of gear arrangement increased the performance of aircraft by reducing the drag.
LARGE AIRCRAFT
As the size of aircraft grows larger, they employ more wheels to with the increasing weight. The airbus A340-500/-600 has an additional four wheel undercarriage bogie on the fuselage centerline. The Boeing 747 has five sets of wheels, a nose-wheel and four sets of four wheel bogies. A set is located under each wing, and two inner sets located in the fuselage, a little rearward of outer bogies.