Abstract. This article provides an overview of the evolution of bypass turbojet engines, examines the structure of modern commercial aircraft engines, the engineering solutions, materials and technologies used in their design. The study highlights the problems that arise when creating ultra-high bypass ratio engines, and also presents the prospects for their further energy efficiency increase. The authors conclude that the development of ultra-high bypass ratio aircraft engines, including propfan ones, is a key direction for achieving high efficiency, fuel economy and environmental friendliness of future aircraft propulsion systems.

Keywords: bypass turbojet engine, bypass ratio, power efficiency, turbofan aircraft engines, composites, propfan propulsion systems.