Abstract: A rotorcraft includes a fuselage, rotors and circular wings. The rotors are attached to the fuselage. The rotors are attached to the fuselage. The circular wings are disposed under the rotors respectively. Upper surfaces of the circular wings have annular curved surfaces and thereby are convex upward respectively. The circular wings cause Coanda effects by the upper surfaces respectively. First lift is generated by rotating the rotors. Second lift is generated by the Coanda effects by the circular wings. Third lift is generated by air jets deflected downward along the upper surfaces of the circular wings respectively.

Abstract: A roadable vehicle includes main wings, a fuselage, a sliding door on a lateral side surface of the fuselage, and hinge mechanisms. The hinge mechanisms connect the main wings to the fuselage. The hinge mechanisms allow the main wings to turn between a first state where the main wings are folded beside the fuselage and a second state where the main wings are opened on the lateral sides of the fuselage. In the first state, the sliding door is opened and closed by sliding the sliding door in a space formed between one of the main wings and the fuselage while an outer side of the fuselage and an inner side of the sliding door facing each other.

Abstract: A fastening structure includes a first structural member, a second structural member, and a fastening member. The first structural member includes a composite material, and has a first electrically-conductive surface having electric conductivity. The second structural member has a second electrically-conductive surface. The second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity. The fastening member penetrates the first electrically-conductive surface and the second electrically-conductive surface, and fastens the first structural member and the second structural member.

Abstract: A land-and-air vehicle configured to switch between a ground traveling mode and an aerial flight mode incudes a body, a wing, a wheel, a suspension, and a lock mechanism. The wing is attached to the body. The wheel is provided on a lower side of the body. The suspension is configured to support the body via the wheel on ground, and to contract due to self-weight of the land-and-air vehicle. The lock mechanism is configured to limit expansion of the suspension from a state in which the suspension has contracted due to the self-weight.

Abstract: A resin impregnation measurement device includes a jig and a resin impregnation sensor. The jig is formed into an inner surface shape of a protrusion of a stringer. The jig includes outer surfaces including a facing surface that is to face an inner surface of the protrusion. The resin impregnation sensor is disposed on the facing surface of the jig.

Abstract: According to one implementation, a composite material structure includes a corrugated stringer and a panel. The corrugated stringer has a corrugated structure including portions each having hat-shaped cross section. The corrugated stringer is made of a composite material. The panel is integrated with the corrugated stringer. The panel is made of a composite material. Further, according to one implementation, a manufacturing method of a composite material structure includes: setting a textile on a laminated body of prepregs; and producing the composite material structure by covering the laminated body with a bagging film, forming a vacuum state in a space covered with the bagging film, impregnating the textile with the resin, and thermal curing of the laminated body of the prepregs. The laminated body is a panel before curing. The textile has a structure corresponding to a corrugated stringer.

Abstract: Provided is an air-ground use vehicle capable of opening and closing a door, while a main wing is folded along a fuselage, without interfering with the main wing. The air-ground use vehicle includes: a main wing; a fuselage; a sliding door provided in a side surface of the fuselage; and a hinge mechanism that connects the main wing to the fuselage and that is capable of rotating between a first state, in which the main wing 4 is folded along the fuselage, and a second state, in which the main wing is opened to a side of the fuselage. In the first state, the sliding door opens and closes by sliding in a space formed between the main wing and the fuselage, with an outer surface of the fuselage and an inner surface of the sliding door facing each other.

Abstract: A resin impregnation measurement system includes first electrodes, second electrodes, a measurement controller, and an impregnation ratio deriving unit. The first electrodes extend in parallel. The second electrodes are disposed so as to oppose to the first electrodes across a container and extend in a direction intersecting the first electrodes. The container is configured to be filled with a resin. The measurement controller is configured to sequentially switch between the first electrodes and the second electrodes and measure electrostatic capacities of measurement regions where the first electrodes are opposite to the second electrodes. The impregnation ratio deriving unit is configured to derive an impregnation ratio of the resin to the fiber base material in the container on a basis of a distribution of the electrostatic capacities of the measurement regions.

Abstract: A composite structure includes a composite member and a fastener. The composite member has a through hole. The fastener is inserted in the through hole and couples the composite member and another part to each other. The composite member includes an electrically-conductive composite member provided at least in part or all of a through-hole portion. The through-hole portion is a portion, of the composite member, having the through hole. The electrically-conductive composite member has a thickness that is greater in a portion, of the electrically-conductive composite member, included in the through-hole portion than in a portion, of the electrically-conductive composite member, other than the through-hole portion.

Abstract: According to one implementation, a composite material structure includes a corrugated stringer and a panel. The corrugated stringer has a corrugated structure including portions each having hat-shaped cross section. The corrugated stringer is made of a composite material. The panel is integrated with the corrugated stringer. The panel is made of a composite material. Further, according to one implementation, a manufacturing method of a composite material structure includes: setting a textile on a laminated body of prepregs; and producing the composite material structure by covering the laminated body with a bagging film, forming a vacuum state in a space covered with the bagging film, impregnating the textile with the resin, and thermal curing of the laminated body of the prepregs. The laminated body is a panel before curing. The textile has a structure corresponding to a corrugated stringer.

Abstract: A method of manufacturing a composite includes bringing a first surface of a first base in which a first fiber base that is to constitute the first base is impregnated with a first resin into contact with a second surface of a second base in which a second fiber base that is to constitute the second base is not impregnated with a second resin, and impregnating the second fiber base with a portion of the first resin with which the first fiber base is impregnated.

Abstract: A land-and-air vehicle configured to switch between a ground traveling mode and an aerial flight mode incudes a body, a wing, a wheel, a suspension, and a lock mechanism. The wing is attached to the body. The wheel is provided on a lower side of the body. The suspension is configured to support the body via the wheel on ground, and to contract due to self-weight of the land-and-air vehicle. The lock mechanism is configured to limit expansion of the suspension from a state in which the suspension has contracted due to the self-weight.

Abstract: A resin impregnation measurement device includes a jig and a resin impregnation sensor. The jig is formed into an inner surface shape of a protrusion of a stringer. The jig includes outer surfaces including a facing surface that is to face an inner surface of the protrusion. The resin impregnation sensor is disposed on the facing surface of the jig.

Abstract: A resin impregnation measurement system includes first electrodes, second electrodes, a measurement controller, and an impregnation ratio deriving unit. The first electrodes extend in parallel. The second electrodes are disposed so as to oppose to the first electrodes across a container and extend in a direction intersecting the first electrodes. The container is configured to be filled with a resin. The measurement controller is configured to sequentially switch between the first electrodes and the second electrodes and measure electrostatic capacities of measurement regions where the first electrodes are opposite to the second electrodes. The impregnation ratio deriving unit is configured to derive an impregnation ratio of the resin to the fiber base material in the container on a basis of a distribution of the electrostatic capacities of the measurement regions.

Abstract: A composite structure includes a composite member and a fastener. The composite member has a through hole. The fastener is inserted in the through hole and couples the composite member and another part to each other. The composite member includes an electrically-conductive composite member provided at least in part or all of a through-hole portion. The through-hole portion is a portion, of the composite member, having the through hole. The electrically-conductive composite member has a thickness that is greater in a portion, of the electrically-conductive composite member, included in the through-hole portion than in a portion, of the electrically-conductive composite member, other than the through-hole portion.

Abstract: A fastening structure includes a first structural member, a second structural member, and a fastening member. The first structural member includes a composite material, and has a first electrically-conductive surface having electric conductivity. The second structural member has a second electrically-conductive surface. The second electrically-conductive surface is in contact with the first electrically-conductive surface and has electric conductivity. The fastening member penetrates the first electrically-conductive surface and the second electrically-conductive surface, and fastens the first structural member and the second structural member.

Abstract: According to one implementation, a composite material structure includes a corrugated stringer and a panel. The corrugated stringer has a corrugated structure including portions each having hat-shaped cross section. The corrugated stringer is made of a composite material. The panel is integrated with the corrugated stringer. The is made of a composite material. Further, according to one implementation, a manufacturing method of a composite material structure includes: setting a textile on a laminated body of prepregs; and producing the composite material structure by covering the laminated body with a bagging film, forming a vacuum state in a space covered with the bagging film, impregnating the textile with the resin, and thermal curing of the laminated body of the prepregs. The laminated body is a panel before curing. The textile has a structure corresponding to a corrugated stringer.

Abstract: A method of reproducing a composition of an electrolytic polishing solution for a niobium material, characterized in that, when the composition of the electrolytic polishing solution for the niobium material which is composed of HF, H.sub.2 SO.sub.4 and water is lowered in the concentration of HF, the composition is replenished with fluorosulfuric acid and water in an amount equimolar therewith or so in order to recover the concentration of HF while the content of water is maintained substantially at a constant level.