Immersed core flow inlet between rotor blade and stator vane for an unducted fan gas turbine

An unducted thrust producing system, comprising:

• a rotating element having an axis of rotation about a central longitudinal axis and comprising a plurality of blades attached to a spinner, wherein the rotating element defines an annular valley positioned between a first annular crown and a second annular crown, the first annual crown having a first radius (R1) measured to the central longitudinal axis;
• a stationary element positioned aft of the rotating element, wherein the stationary element comprises a plurality of vanes and a housing defining an inlet lip such that an inlet is positioned between the rotating element and the stationary element to pass radially inward of the stationary element, wherein the inlet lip defines a forward tip having a lip radius (RL) measured from the forward tip to the central longitudinal axis;
• wherein the inlet lip has a degree of immersion of about 50% to 125% with respect to the first radius of the first spinner crown, where the degree of immersion is calculated according to the formula:
• degree of immersion=(R1)2/(RL)2×100.