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Long endurance naval patrol aircraft of the future will require more efficient advanced turboprop powerplants. Engines used in this kind of application will have performance requirements emphasizing prolonged endurance and very low specific fuel consumption for cruise and part-power loiter operation. Regenerative, regenerative/intercooled and advanced conventional cycle screening studies were carried out to select the cycle pressure ratio and turbine temperature for each type, considering the effects on installed performance and weight. Design and cycle choices were studied in each engine category including recuperator types, effectiveness, pressure drop, bypass bleed and variable area turbine nozzle. The engine characteristics of each type were then compared using a representative mission. The advanced conventional engine showed the largest potential, the regenerative second and the regenerative/intercooled the least promise for lower installed fuel consumption and improved mission performance.