Asymmetric fan nozzle in high-BPR separate-flow nacelle

A fan nozzle for a gas turbine engine, comprising:

• a fan cowl position about a central longitudinal axis of the gas turbine engine and being formed of an upper portion and a lower portion, the upper portion of the fan cowl having a first radius with respect to the central longitudinal axis of the gas turbine engine at a trailing rim of the fan cowl, the upper portion of the fan cowl being formed of a left arcuate member and a right arcuate member, the lower portion of the fan cowl having a second radius with respect to the central longitudinal axis of the gas turbine engine at the trailing rim of the fan cowl, wherein the first radius varies and the second radius is constant and the second radius is less than the first radius;
• a core engine cowl disposed within the fan cowl and positioned about the central longitudinal axis of the gas turbine engine, the core engine cowl being formed of an upper portion and a lower portion, the upper portion of the core engine cowl having a third radius with respect to the central longitudinal axis of the gas turbine engine at a rim of the core engine cowl, the lower portion of the core engine cowl having a fourth radius with respect to the central longitudinal axis of the gas turbine engine at the trailing rim of the core engine cowl, wherein the third radius is constant and the fourth radius varies and the third radius is less than the fourth radius;
• a pylon located between the fan cowl and the core engine cowl;
• and
• an air flow area being defined between the fan cowl and the core engine cowl.

A gas turbine engine, comprising:

• a fan;
• a fan cowl surrounding the fan;
• a core engine cowl disposed within the fan cowl, the core engine cowl surrounding a core engine, the core engine driving the fan, the fan cowl surrounding the core engine cowl and the fan, the fan cowl and the core engine cowl positioned around a central longitudinal axis of the gas turbine engine, the fan cowl having a first trailing rim, the core engine cowl having a second rim, the first trailing rim being formed of an upper portion and a lower portion, the upper portion of the first trailing rim having a first radius with respect to the central longitudinal axis of the gas turbine engine, the lower portion of the first trailing rim having a second radius with respect to the central longitudinal axis of the gas turbine engine, wherein the first radius is constant and the second radius varies and wherein the second radius is less than the first radius,
• the second rim having an upper portion and a lower portion, the upper portion of the second rim having a third radius with respect to the central longitudinal axis of the gas turbine engine, the upper portion of the second rim being formed of a left arcuate member and a right arcuate member, the lower portion of the second rim having a fourth radius semi-circular, wherein the third radius varies and the fourth radius is constant and wherein the third radius is less than the fourth radius;
• a pylon located between the fan cowl and the core engine cowl;
• and
• an air flow area being defined between the fan cowl and the core engine cowl.