A hybrid type rotorcraft having a main rotor, at least two propulsion elements each mounted on respective half-wings arranged symmetrically on either side of an anteroposterior midplane XOZ, a horizontal stabilizer arranged in a rear zone of the rotorcraft on either side of the anteroposterior midplane XOZ, and two fins arranged respectively on either side of the anteroposterior midplane XOZ, each of the two fins comprising a respective left/right bottom fin airfoil arranged below the horizontal stabilizer and a respective left/right top fin airfoil arranged above the horizontal stabilizer.

A collapsible stabilizer assembly to provide directional stability to a windmill or an aircraft is disclosed. The collapsible stabilizer assembly comprises at least one fin 200 having a leading member 202 and a trailing member 204 respectively coupled with a first tube 104 and a second tube 106 that are pivotally fixed to frame 102 of the aircraft. The leading member 202 includes a first hole 208 for engaging a fastening member 302 when the first hole 208 is in alignment with a second hole 108 that is configured in the first tube 104 so as to couple the leading member 202 and the first tube 104. Coupling of the leading member 202 and the trailing member 204 with the first tube 104 and the second tube 106 respectively allows quick installation as well as removal of the at least one fin 200 from the frame 102.

A collapsible stabilizer assembly to provide directional stability to a windmill or an aircraft is disclosed. The collapsible stabilizer assembly comprises at least one fin 200 having a leading member 202 and a trailing member 204 respectively coupled with a first tube 104 and a second tube 106 that are pivotally fixed to frame 102 of the aircraft. The leading member 202 includes a first hole 208 for engaging a fastening member 302 when the first hole 208 is in alignment with a second hole 108 that is configured in the first tube 104 so as to couple the leading member 202 and the first tube 104. Coupling of the leading member 202 and the trailing member 204 with the first tube 104 and the second tube 106 respectively allows quick installation as well as removal of the at least one fin 200 from the frame 102.

A leading edge (3) of a control surface (1) for an aircraft includes a balance weight (6) attached to the forward-most region of the leading edge (3). The control surface (1) rotates with respect to the stabilizer (2) around a hinge line (5). The balance weight (6) is ahead of and adjacent to the most frontal portion (7) of the leading edge (3) of the control surface (1) are is inside the trailing edge of the stabilizer (2). This arrangement allows to have an anti-flutter balance weight without any impact in aerodynamic drag.

A leading edge (3) of a control surface (1) for an aircraft includes a balance weight (6) attached to the forward-most region of the leading edge (3). The control surface (1) rotates with respect to the stabilizer (2) around a hinge line (5). The balance weight (6) is ahead of and adjacent to the most frontal portion (7) of the leading edge (3) of the control surface (1) are is inside the trailing edge of the stabilizer (2). This arrangement allows to have an anti-flutter balance weight without any impact in aerodynamic drag.

A multirotor aircraft that is adapted for vertical take-off and landing. The multirotor aircraft comprises a fuselage, a tail boom that is provided with a vertical fin, a thrust producing units assembly that is provided for producing thrust in operation, at least one lower wing which comprises a lower wing inboard section that is connected to the fuselage and a lower wing outboard section that forms a lower wing tip, and at least one upper wing which is connected to the vertical fin and which forms an upper wing tip. The at least one upper wing is joined to the at least one lower wing in a joined-wing configuration.

A multirotor aircraft that is adapted for vertical take-off and landing. The multirotor aircraft comprises a fuselage, a tail boom that is provided with a vertical fin, a thrust producing units assembly that is provided for producing thrust in operation, at least one lower wing which comprises a lower wing inboard section that is connected to the fuselage and a lower wing outboard section that forms a lower wing tip, and at least one upper wing which is connected to the vertical fin and which forms an upper wing tip. The at least one upper wing is joined to the at least one lower wing in a joined-wing configuration.

A ballistically launched foldable multirotor vehicle has a central body frame. A battery is located in an upper vertical location of the vehicle and positions a center of mass of the vehicle to provide aerodynamic stability during a launch. Fins are attached to the central body frame such that aerodynamic forces on the fins shift an aerodynamic center (AC) of the vehicle downward below the center of mass of the vehicle. Three or more foldable arms are attached to the central body frame via a hinge and exist in two states—a closed state where the foldable arms are parallel to a central body axis, and an open state (after launch) where the foldable arms extend radially outward perpendicular to the central body axis. Rotors mounted to each foldable arm are controlled by a motor to enable flight.

Drag reduction systems and methods for an aircraft include a first vortex generator position on a portion of the aircraft, and a second vortex generator positioned on the portion of the aircraft. The first vortex generator is associated with the second vortex generator. The first vortex generator is asymmetrical to the second vortex generator in relation to a coupling axis in order to offset the longitudinal contribution of the vortex generator to vehicle cross-sectional area.

Drag reduction systems and methods for an aircraft include a first vortex generator position on a portion of the aircraft, and a second vortex generator positioned on the portion of the aircraft. The first vortex generator is associated with the second vortex generator. The first vortex generator is asymmetrical to the second vortex generator in relation to a coupling axis in order to offset the longitudinal contribution of the vortex generator to vehicle cross-sectional area.