Parameters, indexes and performances to estimate the technical and economical perfection of aviation engine in the airplane system are discussed. The index of the engine project creation cost and criterion of its modification, which can be utilized at the preliminary stages of aircraft power plant designing, is offered. Essence of the developed index consists in determination of the engine project cost per one hour of its appointed life-time. The ways of engine designing using minimum existent elements and using maximum of previously designed elements are grounded. The last approach includes development and modification of some subsystems, that finally results in creation of family of engines.
aircraft, criterion, index of cost, aviation engine, power-plant, cost of life cycle of engine, techno-economic efficiency, previous stage of planning, family of engines