Systems and methods for controlling a fixed-wing aircraft during flight are disclosed. The aircraft comprises first and second flight control surfaces of different types. The method comprises determining that a pilot command of the first flight control surface will excite a structural flexible mode of the aircraft and then executing the pilot command of the first flight control surface in conjunction with a command of the second flight control surface to mitigate the effect of the excitation of the structural flexible mode of the aircraft.

An aircraft empennage includes a lower vertical fin member attached to a rear portion of a fuselage, and an upper stabilizer assembly connected to the lower vertical member by an articulating mount configured to allow movement of the upper stabilizer assembly relative to the lower vertical member to adjust pitch trim of the fuselage. The upper stabilizer assembly includes first and second horizontal stabilizer portions and at least one upper vertical member.

An aircraft empennage includes a lower vertical fin member attached to a rear portion of a fuselage, and an upper stabilizer assembly connected to the lower vertical member by an articulating mount configured to allow movement of the upper stabilizer assembly relative to the lower vertical member to adjust pitch trim of the fuselage. The upper stabilizer assembly includes first and second horizontal stabilizer portions and at least one upper vertical member.

A propulsion device with double-layer flow guiding assembly and a flight vehicle using the same are provided. The propulsion device includes a propulsion body, a first-layer flow guiding assembly and a second-layer flow guiding assembly. The propulsion body includes a housing, an airflow suction port and an airflow discharge port. The first-layer flow guiding assembly includes a front flow guiding ring and at least one first-layer flow guiding plate. The front flow guiding ring is disposed outside the airflow discharge port and has a first axis. The front flow guiding ring swings relative to the airflow discharge port along a first rotation axis. The first rotation axis intersects the first axis. The first-layer flow guiding plate is fixed in the front flow guiding ring and extends along the first rotation axis. The second-layer flow guiding assembly has a structure similar to the first-layer flow guiding assembly.

A propulsion device with double-layer flow guiding assembly and a flight vehicle using the same are provided. The propulsion device includes a propulsion body, a first-layer flow guiding assembly and a second-layer flow guiding assembly. The propulsion body includes a housing, an airflow suction port and an airflow discharge port. The first-layer flow guiding assembly includes a front flow guiding ring and at least one first-layer flow guiding plate. The front flow guiding ring is disposed outside the airflow discharge port and has a first axis. The front flow guiding ring swings relative to the airflow discharge port along a first rotation axis. The first rotation axis intersects the first axis. The first-layer flow guiding plate is fixed in the front flow guiding ring and extends along the first rotation axis. The second-layer flow guiding assembly has a structure similar to the first-layer flow guiding assembly.

A variable camber system for an aircraft wing including a wing bracket extending downward from a wing, a flap bracket pivotably coupled to the wing bracket, and a flap pivotably coupled to the flap bracket such that the flap pivots around an axis of rotation through the flap. The variable camber system is configured to adjust position of both the flap and the flap bracket relative to the wing while maintaining position of the flap relative to the flap bracket. The variable camber system is also configured to adjust position of the flap relative to the flap bracket.

A variable camber system for an aircraft wing including a wing bracket extending downward from a wing, a flap bracket pivotably coupled to the wing bracket, and a flap pivotably coupled to the flap bracket such that the flap pivots around an axis of rotation through the flap. The variable camber system is configured to adjust position of both the flap and the flap bracket relative to the wing while maintaining position of the flap relative to the flap bracket. The variable camber system is also configured to adjust position of the flap relative to the flap bracket.

A secondary flight control system comprising: a first flight control surface system; a second flight control surface system; and a power distribution unit operably connected to the first flight control surface system and the second flight control surface system, wherein the power distribution unit is configured to generate torque to actuate the first flight control surface system and the second flight control surface system.

A piezoelectric steering engine of bistable includes a base, four torsion units respectively fixed on the base, and four stiffness devices respectively located at a free end of the four torsion units. The four torsion units share the same structure, and are sequentially arranged at an interval of 90° in a same plane. The four stiffness devices share the same structure and are all connected to rudder blades. Every torsion unit includes a cantilever beam, a first macro-fiber composite actuator and a second macro-fiber composite actuator both of which are respectively attached to two opposite surfaces of the cantilever beam. A first stiffness device includes an elastic ring and a bearing pad mounted inside the elastic ring. After the cantilever beam passes through the bearing pad, a torque is exerted on the cantilever beam by the elastic ring through the bearing pad, resulting in the buckling of the cantilever beam.

A piezoelectric steering engine of bistable includes a base, four torsion units respectively fixed on the base, and four stiffness devices respectively located at a free end of the four torsion units. The four torsion units share the same structure, and are sequentially arranged at an interval of 90° in a same plane. The four stiffness devices share the same structure and are all connected to rudder blades. Every torsion unit includes a cantilever beam, a first macro-fiber composite actuator and a second macro-fiber composite actuator both of which are respectively attached to two opposite surfaces of the cantilever beam. A first stiffness device includes an elastic ring and a bearing pad mounted inside the elastic ring. After the cantilever beam passes through the bearing pad, a torque is exerted on the cantilever beam by the elastic ring through the bearing pad, resulting in the buckling of the cantilever beam.