Abstract: A pressure tight large-scaled membrane structure includes a bag body having a plurality of gores attached to each other along an attachment line, and a plurality of first ropes attached over a predetermined range of the bag body in such a manner as to be orthogonal to the attachment line of the gores, whereby a cylindrical shaped portion is formed. The cylindrical shaped portion has a substantially circular cross-sectional area that is a maximum substantially circular cross-section of the bag body and the plurality of first ropes each having approximately the same length as a circumference of the substantially circular-cross section having a maximum area with respect to the bag body.

Abstract: A pressure tight large-scaled membrane structure comprising a bag body having a plurality of gores attached to each other along an attachment line, and a plurality of first ropes attached over a predetermined range of the bag body in such a manner as to be orthogonal to the attachment line of the gores, whereby a cylindrical shaped portion is formed. The cylindrical shaped portion has a substantially circular cross-sectional area that is a maximum substantially circular cross-section of the bag body and the plurality of first ropes each having approximately the same length as a circumference of the substantially circular-cross section having a maximum area with respect to the bag body.

Abstract: A separable cord connection structure of a parachute, wherein it has a separable cord 11 for being anchored to the airplane via or not via a static cord, a main cord 13 unreleasably fastened to the canopy top of the parachute, and a deployment bag 5 for packing said parachute, and said separable cord 11 has two loops of separable cords 112,113 formed to face each other, and on the other hand, two intersecting coupling loops 141, 142 are formed across one upper end to the other upper end fastened thereto on the side of the separable cord of said deployment bag, characterized in that a rigid pin 12 passes through the loops of the two separable cords, further, passing through the loops formed by the intersection of said coupling loops, further, passing through a metallic guide in the separable cords, and one end part is temporarily fastened to the separable cords, the other end part is connected to the main cord, and said main cord has a branch 131, and said branch is fastened to the pack.