Adjustable nozzle for a solid-propellant engine, and engine featuring such an adjustable nozzle

In a solid-propellant engine (1), a variable-throat nozzle (6) has a conduit (10) for conducting the gases produced by combustion of a solid propellant, and a choke device (16) for varying a reference section (11) of the conduit; the choke device (16) in turn having a choke body (18) movable with respect to the conduit (10), and a wearable, controlled-wear member (25) for maintaining the choke body (18) in a rest condition, and allowing movement of the choke body (18) into a choke position choking the reference section (11) after a predetermined time.