Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . ut 50 , with hemispherical ends,having a radius of 10 ft. Theshape is preserved by the useof an air-bag, with a capacity of5,300 cubic feet; an ingeniousarrangement is used by whichit is automatically filled by thewind under pressure. Sup-pose the balloon to be slightlyinclined to the horizontal, andthat a section is made on ahorizontal plane passingthrough the middle of thelower hemispherical end. Theair-bag is then fastened to thebody of the bal
Airships past and present, together with chapters on the use of balloons in connection with meteorology, photography and the carrier pigeon . ut 50 , with hemispherical ends,having a radius of 10 ft. Theshape is preserved by the useof an air-bag, with a capacity of5,300 cubic feet; an ingeniousarrangement is used by whichit is automatically filled by thewind under pressure. Sup-pose the balloon to be slightlyinclined to the horizontal, andthat a section is made on ahorizontal plane passingthrough the middle of thelower hemispherical end. Theair-bag is then fastened to thebody of the balloon round theedge of this sectional is therefore joined to boththe hemispherical and cylin-drical portions, and forms asort of inner envelope, leaving,however, a space between thetwo, into which the air can bedriven by the wind. In thisstate the balloon must be sup-posed to be fully inflated. Assoon as it rises, the gasexpands, and the pressure onthe envelope wTould increase tothe bursting point if the gaswere not allowed to escape. The valve is however opened bya cord as soon as the air-bag is completely emptied. The careful. Fig. 115a.—The kite-balloon designedby Major von Parseval and Majorvon Sigsfeld. BALLOON CONSTBUCTION, ETC, 189 adjustment of this rope is therefore a matter of great soon as the volume of the balloon begins to contract, air entersthrough an opening into the air-bag, and the valve closes of itsown accord. A non-return valve prevents the air from escaping,and the capacity of the air-bag is about 5,300 cubic feet, when it is completely air is slightlycompressed by theaction of the gustsof wind, and thispressure extends tothe hydrogen andreacts upon theenvelope. This isresisted by an in-ternal pressure equalto that on the out-side, and also by thestatic pressure actingon the top of theballoon, which, ac-cording to Parsevalsreckonings, amountsto the pressure of acolumn of water, 0*3or 04 in. high. Ifthere is a sufficiencyo
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Keywords: ., bookcentury1900, bookdecade1900, bookpubl, booksubjectaeronautics
