Jumbo Koinobori

Children’s Day, May 5, is celebrated in Japan by flying carps made of fabric. The normal size of flying carps is 3 to 5m in length. Kazo is a city which is famous for production of the fabric carps. In 1988, the city people consulted us after a failing experience about the possibility of flying a 100-meter-long carp that they had made for the purpose of advertising their city. There were three questions asked; Could the jumbo carp fly? If it could fly, how would it fly? Could the cotton skin stand stress during the flight? A dimensional analysis for flying conditions of the jumbo carp, a calculation of membrane stresses, and a series of wind-tunnel tests were undertaken, and the answers to the above questions were all obtained. After implementing improvements to the original design, the jumbo carp, a huge flying membrane, began to fly with the breeze and swam elegantly in the sky.