US Patent 10260427 Variable area bypass nozzle

A gas turbine engine includes a first duct, a second duct, and a bladder. The bladder is disposed in the first duct and communicates with the second duct. A first gas flow is capable of passing through the first duct and a second gas flow is capable of passing through the second duct. The bladder is adapted to receive a bleed gas flow from the second duct and inflate within the first duct, thereby decreasing an area in the first duct through which the first gas flow is capable of traveling.