Author/Authors :
Yoshitaka Saito، نويسنده , , Eiji Kamioka، نويسنده , , Michihiko Toriumi، نويسنده , , Yukihiko Matsuzaka، نويسنده , , Michiyoshi Namiki، نويسنده , , Naoki Izutsu، نويسنده , , Shigeo Ohta، نويسنده , , Takamasa Yamagami، نويسنده , , Jun. Nishimura، نويسنده , , Kiyoho Matsushima، نويسنده ,
Abstract :
For a new balloon material, we have been studying the properties of an EVAL (Ethylene-Vinyl-ALcohol) film during a part of few years. The EVAL film is a product of Kurare Plastic Company, and has mechanical properties similar to that of a Mylar film. Besides this strong mechanical strength, we found that the EVAL film has several characteristics which seems to be suitable for the balloon material. Those are:
1.
1. Sandwiched EVAL films laminated by polyethylene films can be heat-sealed,
2.
2. Gas leakage through the EVAL film is extremely low, and for Helium gas, it is almost 100 times less than that of a Mylar film,
3.
3. The EVAL film is transparent in the optical band, while it efficiently absorbs the infrared radiation from the earth.
In 1997, we have carried out a test flight from the Sanriku Balloon Center using a small balloon with a volume of 1000 m3. The balloon reached an altitude of 22 km successfully and showed a maximum burst pressure of 2.1 g/cm2.
In this paper, basic properties of the EVAL film and performance of the test balloon a
