Test of Pilot-balloons

Abstract

The author tested the breaking limit of gummy balloons made in Japan. Those having weight of 23gr. break at about the diameter of about 75cm. While the diameter suitable to the asccnt of 150m/min is about 54cm. Leakage of hydrogen into the air from the balloon with this diameter is about 4gr. per hour.
By equating the bouyan_??_y with the resistance of during the ascent of balloon the author obtained an equation
where D is the diameter of the balloon, V its ascending velocity assumed to be a constant, W+ω is its weight with hydrogen, ρ is the density weight of the surrounding air and K is the constant of resistance. Solving this equation he obtained the value of D, with corresponding ρ which is a known function of height for average atmosphere. So that the diameter of the balloon, at any hight can be given. Hence the height at which the balloon comes to have the diameter of breaking limit can be obtained. He, however, not yet check the formula with the data of aetual observation.