Формування областей основних параметрів модифікацій транспортного літака за умовами його базування

Along with the unique flight performance indicators and economic indicators that characterize heavy transport aircraft, the priority is also to ensure the basing for their heavier modifications at the airfields declared for the base aircraft. This problem arises at the very early stage of the modification creation, when its main parameters such as the gross mass at takeoff and thrust-to-weight ratio are formed. This is due to the very essence of creating a modification ‑ increasing its carrying capacity (which leads to increase in the gross mass at takeoff and flight range ) with an increased payload by increasing the mass of fuel on board. Ensuring growth of flight and hour , performance underlies the creation of all modifications of transport category aircraft. For heavier modifications than their base aircraft, it is further complicated by the fact that the base models are based on the runways of the second and first class airfields, which creates an insurmountable limitation on the available runway length. The second limitation is the value of the decision-making speed during takeoff, in case of failure of the critical engine during the takeoff run, which predetermines the required length of the runway. Since the takeoff masses of aircraft modifications of this type continue to increase, the problem of their basing on the runways of existing airfields arises by forming the takeoff weight relationship – decision-making speed in case of a critical engine failure ‑ thrust-to-weight ratio, providing the basing of a heavier modification at the airfield declared for the base aircraft . To implement this condition, a model for determining the speed , in which a safe termination of the takeoff run is possible in the event of a critical engine failure. The resulting model allows to take into account a number of restrictions due to the properties of heavy aircraft, such as the minimum and maximum thrust of the cruise engines, which makes it possible to make reasonable recommendations in the operating rules for aircraft of this type. Taking into account the expressions obtained to determine , a model has been formed to determine and assess the required thrust-to-weight ratio of a heavier modification by condition for modifications with a takeoff weight of more than 300 tons. It has been established that the required relative thrust-to-weight ratio should be within . Defining parameters such as , and is the basis for the implementation of other modification changes in the heavy transport aircraft.