Nozzle extension for a jet engine and method for producing and cooling a nozzle expansion

Nozzle extension (10) for an engine (74), with a nozzle casing (18) defining a flow cross section (24) which extends from a nozzle extension input (14) extended towards a nozzle expansion outlet (16), the nozzle extension input (14) a combustor exit (54) of a combustion chamber (44) of an engine (74) is connectable, characterized in that the nozzle casing (18) at least two, made of a ceramic fiber composite material, relative to each other fixed shell elements (26, 28, 142), wherein at least two shell elements (26, 28, 142) are integral with one another and spaced from one another, wherein the distance between the at least two shell elements (26, 28, 142) from the nozzle extension input (14) decreases in the direction of the nozzle expansion outlet (16).