Embodiments for aircraft keel beam assembly. One embodiment is a keel beam assembly of an aircraft. The keel beam assembly includes a keel attach chord to connect to a wing center section of the aircraft, the keel attach chord extending in a longitudinal direction between a rear spar and front spar of the aircraft. The keel beam assembly also includes a lower chord disposed underneath the keel attach chord and extending in the longitudinal direction between an aft wheel well bulkhead and a forward bulkhead of the aircraft. The keel beam assembly further includes a forward web to couple the keel attach chord and the lower chord, the forward web including a front edge extending in a diagonal direction from the keel attach chord that is downward and aft toward the lower chord to create an open area forward from the front edge.

An airfoil structure for an aircraft includes a spanwise-extending load-carrying member, a leading-edge structure, a trailing-edge structure, an upper cover, and a lower cover. The load-carrying member is configured to react more than half of all flight loads experienced by the airfoil structure during flight and is configured to have selected stiffness properties selected such that the airfoil structure bends and twists in a predefined manner in response to applied flight loads. The leading-edge structure is configured to form a leading-edge part of an aerodynamic surface of the airfoil structure. The trailing-edge structure is configured to form a trailing edge part of the aerodynamic surface. The upper cover is configured to form an upper part of the aerodynamic surface. The lower cover is configured to form a lower part of the aerodynamic surface.

A method of manufacturing a cured composite structure includes placing a radius filler element into a radius cavity extending along a length of a composite base member. The radius filler element is formed of a permeable material. The method also includes absorbing resin from the composite base member into the permeable material of the radius filler element. The method additionally includes curing or solidifying the resin in the radius filler element and in the composite base member to form a cured composite structure in which the resin bonds the radius filler element to the composite base member.

Described herein are aircraft, comprising rear spar integration assemblies, and methods of manufacturing these aircraft. Specifically, an aircraft comprises a keel beam and a center wing box, comprising a rear spar. The rear spar is attached to the keel beam using a rear spar integration assembly. The assembly comprises a rear spar stiffener, attached to the rear spar, and having a stiffener load axis. The assembly also comprises and a keel beam fitting, attached to the keel beam, and having a fitting load axis. The rear spar stiffener is also attached to the keel beam fitting, e.g., using splice plates. More specifically, the fitting load axis is offset relative to the stiffener load axis along the primary axis of the aircraft. This offset is designed to compensate for a bending moment at the keel beam-rear spar interface, which allows reducing the size and/or the number of fasteners needed.

A vertical takeoff and landing aircraft takeoff/land as a multirotor and cruises as an airplane. The aircraft comprises two major parts: a winged carrier frame comprises wings, engines, propellers and landing gears; a tilting fuselage comprises cockpit, cabin and tail. The winged carrier frame is basically an X/H frame multirotor in which its thruster carrying arms are wing shaped. The aircraft can vertical takeoff as a multirotor aircraft after gaining safe altitude and forward airspeed the aircraft changes its flying axis that the wings and the thrust direction parallel to the horizon. The lift generated by the wings and thrust generated by the thrusters that aircraft has basic airplane flying characteristics. The fuselage tilted to keep the crew, passengers and payload relatively parallel to the horizon. The speed is reduced then the winged carrier frame and the tilting fuselage returned to multirotor mode for the landing.

Embodiments for aircraft keel beam assembly. One embodiment is a keel beam assembly of an aircraft. The keel beam assembly includes a keel attach chord to connect to a wing center section of the aircraft, the keel attach chord extending in a longitudinal direction between a rear spar and front spar of the aircraft. The keel beam assembly also includes a lower chord disposed underneath the keel attach chord and extending in the longitudinal direction between an aft wheel well bulkhead and a forward bulkhead of the aircraft. The keel beam assembly further includes a forward web to couple the keel attach chord and the lower chord, the forward web including a front edge extending in a diagonal direction from the keel attach chord that is downward and aft toward the lower chord to create an open area forward from the front edge.

A reinforced structural component includes a body portion made of a combination of plastic material and chopped fibers. The body portion has a central longitudinal axis and a cross-section orthogonal to the central longitudinal axis, with the cross-section having an outer periphery and an inner core inward of the outer periphery. The body portion has an outer peripheral portion and an inner core portion corresponding to respective longitudinal projections of the outer periphery and inner core. The body portion is configured for being acted upon by a combination of forces causing tension within one or more longitudinal segments of the inner core portion. The reinforced structural component also includes one or more layers of continuous fiber disposed longitudinally within the one or more longitudinal segments, so as to resist tension caused within the one or more longitudinal segments.

A convertible aircraft system is provided that can convert to a helicopter configuration, an airplane configuration, or a gyroplane configuration before, during, or after flight. The convertible aircraft system includes a fuselage, a proximal flight assembly, a distal flight assembly, a support spar, and a tail assembly. The fuselage is the main structural body of the present invention. The proximal flight assembly and the distal flight assembly are the flight system of the present invention. The support spar provides an axis of rotation and a pole support for the proximal flight assembly and the distal flight assembly. The tail assembly provides stability during flight of the present invention. In more detail, the tail assembly may comprise at least one vertical stabilizer, at least one horizontal stabilizer, and at least one rudder in order to provide stability during flight of the present invention.

An aircraft empennage includes a vertical tail plane, a rear fuselage section attached to the vertical tail plane and including a skin and internal reinforcing members, a horizontal tail plane comprising two lateral torsion boxes and a framework located between the two lateral torsion boxes comprising a front spar, a rear spar and two ribs extending between the front and the rear spar and each adjacent to a lateral torsion box. The framework encloses a portion of the vertical tail plane along its spanwise direction. The aircraft empennage includes an attachment assembly attaching the framework to the rear fuselage section, the attachment assembly crossing the skin and extends between the internal reinforcing members of the rear fuselage section and the framework.

A method for producing a torsion box for a structure of an airplane. The method includes providing a first component made of a fiber composite material, the first component has a first planar base having a first inner side and a first outer side, first stiffening elements on the first inner side forming a composite with the first base. A second component is provided of a fiber composite material and has a second planar base having a second inner side and a second outer side. Second stiffening elements are on the second inner side and form a composite with the second base. The method includes superimposing the first component and the second component such that the first stiffening elements lie, at least in some areas, on the second inner side and the second stiffening elements lie, at least in some areas, on the first inner side. The methods includes connecting the first stiffening elements to the second base and connecting the second stiffening elements to the first base.