Abstract: A pneumatic tire that includes a tread surface 1 including: two or more main grooves 3; and a pair of middle block rows 22, wherein one or more first middle blocks in the plurality of middle blocks each have a middle block inclined side wall surface 223 that faces an outer main groove in the pair of outer main grooves and that gradually inclines inwards in a tire radial direction as the middle block inclined side wall surface extends outwards in the tire width direction, and the middle block inclined side wall surface forms an acute angle ?223 of 30° to 50° with respect to a normal of the tread surface at an inner end in the tire width direction of the middle block inclined side wall surface.

Abstract: A pneumatic tire including a center block row 21 provided in a center area of a tread surface 1, wherein the center block row includes a plurality of center blocks 210 arranged along a tire circumferential direction, the plurality of center blocks includes a plurality of first center blocks 211 and a plurality of second center blocks 212, the plurality of first center blocks and the plurality of second center blocks have polygonal shapes on the tread surface, the polygonal shape formed by each second center block has a same number of sides as, but a different shape than, the polygonal shape formed by each first center block, each first center block and each second center block has one or more sipes, and a number n of sipes included in each second center block is greater than a number m of sipes included in each first center block.

Abstract: A cooling duct configured to introduce air flow to a cooling target device provided in a helicopter body of a helicopter includes a duct body, a front opening, an upper opening, a hinge, and a movable blade. The duct body is mountable below a main rotor of the helicopter to be adjacent to the cooling target device. The front opening is formed on a forward side of the helicopter body in the duct body. The upper opening is formed on an upper side of the helicopter body in the duct body. The hinge is disposed in an upper portion of the duct body and includes a pivot shaft extending in a lateral direction of the helicopter body. The movable blade with an end that is pivotally supported by the hinge is provided to be pivotable about the pivot shaft between a first position and a second position.

Abstract: A cooling duct configured to introduce air flow to a cooling target device provided in a helicopter body of a helicopter includes a duct body, a front opening, an upper opening, a hinge, and a movable blade. The duct body is mountable below a main rotor of the helicopter to be adjacent to the cooling target device. The front opening is formed on a forward side of the helicopter body in the duct body. The upper opening is formed on an upper side of the helicopter body in the duct body. The hinge is disposed in an upper portion of the duct body and includes a pivot shaft extending in a lateral direction of the helicopter body. The movable blade with an end that is pivotally supported by the hinge is provided to be pivotable about the pivot shaft between a first position and a second position.