US Patent 8690097 Variable-geometry rotating spiral cone engine inlet compression system and method

The present disclosure is generally directed to a system, aircraft and a method of operation of an aircraft engine including an intake portion and an exhaust portion, an engine inlet, oriented in a forward direction to the intake portion, the engine inlet defined by a peripheral cowling that directs airflow to the intake portion of the aircraft engine, and a spiral cone positioned proximate the engine inlet, the spiral cone including a variable compression surface area that directs airflow immediately in front of the engine inlet.