A shrouded rotor assembly for an aircraft. The shrouded rotor assembly comprises a stator hollow structure comprises formed from a plurality of composite angular segments. Each composite angular segment includes: a core arched section of a central hub casing, a peripheral rim section of an external hollow duct and a pair of angularly opposed sliced portions, respectively for one of a pair of guide vanes. The resulting stator hollow structure is a unitary one-piece, integrating together continuously the composite angular segments. The invention typically applies e.g. to aircrafts such as rotary wing aircrafts.