A gas
turbine engine defining a centerline and a circumferential direction, the gas
turbine engine comprising: a turbomachine comprising, in serial flow order, a compressor section, a
combustion section, and a
turbine section, the turbomachine defining a working gas flow path and a fan duct flow path; a primary fan driven by the turbomachine, the primary fan defining a primary fan tip
radius R1 and a primary fan hub
radius R2; a secondary fan downstream of the primary fan and driven by the turbomachine, at least a portion of
airflow from the primary fan being configured to bypass the secondary fan, the secondary fan defining a secondary fan tip
radius R3 and a secondary fan hub radius R4, wherein the secondary fan is configured to provide, during operation, a fan duct
airflow through the fan duct flow path to generate a fan duct thrust, wherein the fan duct thrust is equal to a %Fn of a total engine thrust during operation of the gas turbine engine at rated speed during standard day operating conditions 3S ; wherein a ratio of R1 to R3 is equal to wherein EFP is between 1.5 and 11, wherein RqR Prim.‑Fan is a ratio of R2 to R1, and wherein RqR Sec.‑Fan is a ratio of R4 to R3.