c) At the present work, a detailed analysis of the thermodynamic cycle of a gas turbine operating with low pressure ratio for heli engine configurations was performed. The conditions of the selected configuration were based on data found in open literature. A heat exchanger core of circular tubes was designed respecting the heli engine geometrical limitations, implementation constraints and operational conditions, The heat exchanger sizing utilized heat transfer related correlations from literature. The assessment of the heat exchanger performance was carried out with detailed CFD computations including integration aspects of the heat exchanger detail geometry in the heli engine configuration. The computational results were used for the calculation of pressure loss and heat transfer characteristics. Finally, an assessment of the heat exchanger thermal and hydraulic effect was performed on a thermodynamic model of a recuperative heli engine which included the derived performance characteristics of the heat exchanger. The results presented a thermal efficiency improvement of 10.6% and fuel consumption reduction of 9.3%. The investigated heli engine was compared to a non-recuperative one of similar technological level, showing the existing significant potential for optimization based on recuperation technology for designing more cost-efficient and environmentally friendly heli engines. (C) 2018 Elsevier Ltd. All rights reserved.