Tham khảo tài liệu 'aircraft design - systhesis anh analysis 2008 part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | An aircraft does not have a single number that represents its range. Even the maximum range is subject to interpretation since the maximum range is generally not very useful as it is achieved with no payload. To represent the available trade-off between payload and range a range-payload diagram may be constructed as shown in the figure below. At the maximum payload weight is often constrained by the aircraft structure which has been designed to handle a certain maximum zero fuel weight. Sometimes the maximum payload weight is limited by volume but this is rather rare. It has been noted that the MD-11 would exceed its maximum zero fuel weight if the fuselage were filled with ping pong balls. So the airplane take-off weight can be increased from the zero fuel weight by adding fuel with a corresponding increase in range. This is the initial flat portion of the payload-range diagram. At some point the airplane could reach a limit on maximum landing weight. This usually happens only when the required reserve fuel is very large. Usually we can increase the weight until the airplane reaches its maximum take-off weight with the full payload. If we want to continue to add fuel and range from this point on we must trade payload for fuel so as not to exceed the maximum take-off weight. At some point the fuel tanks will be full. We could increase the range further only by reducing the payload weight and saving on drag with a fixed fuel load. This is the final very steep portion of the payload range diagram. Usually we are most interested in the range with maximum take-off weight and here we will focus on the range of the aircraft with a full compliment of passengers and baggage. This point is somewhere on the portion of the curve labeled maximum take-off weight but often at a point considerably lower than that associated with maximum zero fuel weight since the maximum zero fuel weight may be chosen to accommodate revnue cargo on shorter routes and to provide some growth .
