Movable exhaust nozzle flap of a turbomachine with extended durability

The flap has a conical hollow body and a rectilinear generator (11). The body has a thin wall (12) that is divided transversally into a cold wall (14) and a warm wall (13) and two symmetrical lateral walls (15). The thin wall has a continuous inner surface with bend radius equal to twice the thin wall thickness. The thin wall is made of a composite refractory material with reinforcement fibers (18) embedded in a matrix. An independent claim is also included for a manufacturing process of a nozzle flap.