Rotary combustion engine comprising: - a frame forming a stator in which is formed a cavity extending along a longitudinal axis and having at least one first transverse dimension termed the greater width and a second transverse dimension termed the lesser width, which longitudinal axis is immobile relative to the frame, - a rotor comprising a cylindrical body extending longitudinally in the cavity and mounted to be mobile in rotation in the frame about the longitudinal axis, which cylindrical body has a diameter corresponding to the lesser width of the cavity and defines two opposite zones (48a, 48b) flush with the surface of the cavity forming a bottleneck that separates the cavity in sealed manner into an oxidant gas intake compartment and a burnt gas exhaust compartment, each of the intake and exhaust compartments (7, 8) being delimited by said external face of the cylindrical body and said surface of the cavity and being respectively in fluidic communication with an oxidant gas intake inlet and a burnt gas exhaust outlet formed in the wall of said frame, - said rotor comprising at least one member (9a, 9b) for driving the gases contained in the compartments (7, 8) mounted in a longitudinal opening formed in the cylindrical body of the rotor and configured to be driven in rotation by said cylindrical body about the longitudinal axis, - said engine comprising means whereby the free ends (45a, 45b) of the drive members (9a, 9b) are flush with the internal face of the cavity by sliding of said drive members (9a, 9b) in the opening in a direction perpendicular to the longitudinal axis between a minimal position in which its free end (45a, 45b) is flush with the internal face of the cavity at the level of its lesser width and a maximal position in which its free end (45a, 45b) is flush with the internal face of the cavity at the level of its greater width, and - an alternated combustion device comprising means (19, 20) for injecting fuel into a combustion chamber (14, 15) and combusting it therein fluidically connected to an oxidant gas inlet in fluidic communication with the intake compartment and to a burnt gas outlet in fluidic communication with the exhaust compartment via an alternated fluidic communication device (16, 17, 18) configured to place the combustion chamber (14, 15) alternately in fluidic communication with the oxidant gas inlet and the burnt gas outlet. - a frame forming a stator in which is formed a cavity extending along a longitudinal axis and having at least one first transverse dimension termed the greater width and a second transverse dimension termed the lesser width, which longitudinal axis is immobile relative to the frame, - a rotor comprising a cylindrical body extending longitudinally in the cavity and mounted to be mobile in rotation in the frame about the longitudinal axis, which cylindrical body has a diameter corresponding to the lesser width of the cavity and defines two opposite zones (48a, 48b) flush with the surface of the cavity forming a bottleneck that separates the cavity in sealed manner into an oxidant gas intake compartment and a burnt gas exhaust compartment, each of the intake and exhaust compartments (7, 8) being delimited by said external face of the cylindrical body and said surface of the cavity and being respectively in fluidic communication with an oxidant gas intake inlet and a burnt gas exhaust outlet formed in the wall of said frame, - said rotor comprising at least one member (9a, 9b) for driving the gases contained in the compartments (7, 8) mounted in a longitudinal opening formed in the cylindrical body of the rotor and configured to be driven in rotation by said cylindrical body about the longitudinal axis, - said engine comprising means whereby the free ends (45a, 45b) of the drive members (9a, 9b) are flush with the internal face of the cavity by sliding of said drive members (9a, 9b) in the opening in a direction perpendicular to the longitudinal axis between a minimal position in which its free end (45a, 45b) is flush with the internal face of the cavity at the level of its lesser width and a maximal position in which its free end (45a, 45b) is flush with the internal face of the cavity at the level of its greater width, and - an alternated combustion device comprising means (19, 20) for injecting fuel into a combustion chamber (14, 15) and combusting it therein fluidically connected to an oxidant gas inlet in fluidic communication with the intake compartment and to a burnt gas outlet in fluidic communication with the exhaust compartment via an alternated fluidic communication device (16, 17, 18) configured to place the combustion chamber (14, 15) alternately in fluidic communication with the oxidant gas inlet and the burnt gas outlet.