a gas turbine engine comprises a gear train defined along an axis . a spool along the axis drives the gear train and includes a low stage count low pressure turbine . a fan i s rotatable at a fan speed about the axis and driven by the low pressure turbine through the gear train . the fan speed is less than a speed of the low pressure turbine . a core is surrounded by a core nacelle defined about the axis . a fan nacelle i s mounted at least partially around the core nacelle to define a fan bypass airflow path for a fan bypass airflow . a bypass ratio defined by the fan bypass passage airflow divided by airflow through the core is greater than about ten .