Models of early stages of design of trunk-route passenger airplanes with taking families into account

There is a tight connection between the Pre-Design (development of requirements for the designed airplane) and Conceptual Design stages while creating a new aircraft. Taking this connection into account would result in the design of more optimal aircraft that would have the appropriate advantage during operation. Previously when the ability to take such interconnections into the account was lacking the designers were forced to allocate certain reserves in the project based on previous design experience. The advancement of design, modeling and manufacturing methods allowed transitioning from allocating these reserves as means for possible error compensation to their planning or management. In particular, such planned reserves should be allocated in wing and landing gear at the Conceptual Design stage for the creation of passenger airplane families. The values of these reserves should be substantiated based on the evaluation of future functioning of the whole created airplane family within the airline fleet. This requires solving a problem of Pre-Design and requirements creation. Thus, the reserves become new design variables. The values of these new variables should be optimized together with the values of the existing “traditional” variables during airplane design. A model, which takes management of the aforementioned reserves into the account during airplane design, was constructed. The presented model is intended for usage within the framework of the models, which solve the problem of creation of a passenger airplane fleet at Pre-Design stage with taking the presence of an airplane family within this fleet into the account as well as optimization of this passenger airplane family. The model calculation results were verified for the trunk-route passenger airplanes of all main types with taking the existence of the appropriate families into the account. During verification the wing of each considered passenger airplane was sized for the appropriate family version with the maximum take-off weight. After that this wing was “fixed” and processed as initial data for the family version, statistics on which was used for checking the model calculation results. The verification demonstrated good correlation between the model calculation results and the available statistics. It also showed that the presented model can be used for the design of individual trunk-route passenger airplanes and families of all main types (short-, medium- and long-range).