Purpose The purpose of this work is to further develop the methodology for calculating the aircraft take-off mass and its main functional components for the conceptual analysis and synthesis of new projects. Design/methodology/approach The method is based on the assessment of changes in the take-off gross mass (TOGM) of the already developed project or already existing a basic version of the aircraft when making local mass changes for its modification or for the numerical researches to create a more advanced project. The method is based on the “sensitivity factors of mass” (SFM) of aircraft, which represents the ratio of TOGM to initial (local) mass changes of its main functional components. The method of analytical refined calculation of SFM for the initial mass change and the main aerodynamic characteristics is given. Findings In comparison with the long-known method based on weight (mass) growth factors, which were considered constant, this method takes into account the dependence from the value of the initial local mass change and its functional purpose. Practical implications This method allows the designer to calculate more strictly the final changes in the TOGM on the initial stages of conceptual design when finding new project solutions. Numerical calculations are given on the example of passenger aircraft. The dependence of SFM and TOGM and its functional masses on the value of the initial change of the structure mass are shown. This method is used in the educational process at the college of Aerospace Engineering in the Aircraft Design department. Originality/value The considered method based on SFM is simple and convenient and more accurate for conducting project research on many project parameters when analyzing and synthesizing a new project.

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The effect of heating on the mass of load-carrying structures is analyzed using the weight Komarov formula in the framework of the design calculations by examples of a panel and spar. The results obtained have been compared with the data on real structures of supersonic passenger aircraft and aerospace aircraft of reusable transport systems.Weight is a major factor in aircraft design as well as one of the main criteria being used. The structure, which takes all spectrum of acting loads, accounts for the greatest share of aircraft weight. There are tens and even hundreds of the so-called weight equations to estimate the structure mass at the early design stages. Let us apply the general-purpose Komarov weight equation [1] in the following form:

A mass-economic assessment of replacement of aviation kerosene with cryogenic fuel is carried out based on the analysis of the mass sensitivity to the initial change in the aircraft parameters and on an example of transferring the Tu-204 aircraft to liquefied natural gas (Tu-206 project).

The application of the wings with a high aspect ratio for future-oriented transport category aircraft is being considered. Such a solution makes it possible to increase fuel efficiency by reducing induced drag. This goal is achieved by increasing the wingspan, when the wings made of composite materials are used. The wings of an increased span complicate the arrangement of the aircraft in the existing infrastructure of airports. To eliminate this drawback, the application of folding wingtips was considered. The effect of such a folding device on the mass of the airplane was estimated. The approach to estimating the mass of composite structures with folding wingtips has been proposed. A conceptual assessment of the Boeing 737 and A-320 aircraft with higher aspect ratio composite wings was performed.

The purpose of this research is to improve the approach for evaluating of new design solutions based on sensitivity analysis of takeoff mass (SFM) to initial changes in the basic project. The approach is based on the changes assessment in maximum takeoff mass of a developed project or an already existed basic variant of an aircraft with local design (project) changes, including the aerodynamic ones, that ensure the developing of a more advanced aircraft. In comparison with the existed known approaches based on the mass growth factors, which were considered constant, the proposed approach takes into account more exactly the dependence of the takeoff mass on the initial local change in mass in terms of their functional purpose, as well as the aerodynamic characteristics. This approach allows the designer to calculate more precisely the final maximum takeoff mass changes in the early (preliminary) stages of conceptual design when looking for new design solutions. On numerical examples, carried out on the examples of transport category airplanes, a significant dependence of the wing aspect ratio influence on fuel efficiency is shown. The considered approach using SFM with semi-analytical aerodynamic analysis combination is simple, reliable and convenient in the analysis and synthesis of a new project for the design process based on the base variant.

One of the success indicators for any new aircraft is its fuel efficiency, influencing both range and cost-effectiveness, as fuel costs amount to 30% of direct operating costs. Based on the analysis of take-off mass response to design changes, a solution to the basic-type aircraft improvement in terms of fuel efficiency is considered. The feature of proposed redesigning is the use of a higher aspect- ratio of an airfoil allowing for fuel efficiency to be increased by reducing the induced drag. Two solutions are considered to substantiate this approach. The first one is the transition to composite wing structures, which will allow for a high aspect ratio of an airfoil without losing rigidity. The second one is the application (if necessary) of devices, reducing the wingspan, caused by the airport restrictions. The methodology for assessing the mass of composite wings based on the universal weight formula by V.A. Komarov which was specified by applying an integral factor considering the features of mass distribution in the structure, the structural adaptation of structure elements and their strength performance, has been proposed. To simplify the arrangement of aircraft with large-span wings in the available airport layout, the application of folding wingtips was considered. The principal analysis of the wingtip swiveling unit structure was performed. The assessment of the folding device effect upon the mass of a passenger aircraft was completed. The proposed approach was verified based on the Boeing company of B777 aircraft family. The numerical analysis of the composite wing application for the IL-96, Tu-214 and SSJ-100 was performed, and the winglet use effect on the MC-21 aircraft was studied.

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