This project involves using flammable materials to create a miniature hot-air balloon, and because of the danger of fire, the balloon should be ignited and flown only under the supervision of adults and with the appropriate safety precautions including a fire extinguisher. The balloon should be flown only over water.
This type of balloon, made spherical or designed like the regular aeronaut's hot-air balloon, are the best kind to make. Those having an odd or unusual shape will not make good ascensions, and in most cases, the paper will catch fire from the torch and burn before they have flown very far. The following description is for making a tissue-paper balloon about 6 ft. high.
The paper may be selected in several colors. The gores cut from these and pasted in alternately will produce a pretty array of colors when the balloon is in flight. The shape of a good balloon is shown in Fig. 1. The gores for a 6-ft. balloon should be about 8 ft. long or about one-third longer than the height of the balloon. The widest part of each gore is 16 in. The widest place should be 53 1/2 in. from the bottom end, or a little over halfway from the bottom to the top. The bottom of the gore is one-third the width of the widest point. The dimensions and shape of each gore are shown in Fig. 2.
The balloon is made up of 13 gores pasted together, using about 1/2-in. lap on the edges. Any good paste will do--one that is made up of a well-cooked mixture of flour and water will serve the purpose. If the gores have been put together correctly, the pointed ends will close up the top entirely and the wider bottom ends will leave an opening about 20 in. in diameter. A light wood hoop having the same diameter as the opening is pasted to the bottom end of the gores. Two cross wires are fastened to the hoop, as shown in Fig. 3. These are to hold the wick ball, Fig. 4, so that it will hang as shown in Fig. 5. The wick ball is made by winding wicking around a wire, with the wire ends bent into hooks as shown.
The balloon is filled with hot air in a manner similar to that used with the ordinary cloth balloon.A small trench or fireplace is made of brick with a chimney over which the mouth of the paper balloon is placed. Use fuel that will make heat with very little smoke. Hold the balloon so it will not catch fire from the flames coming out of the chimney. Have some alcohol ready to pour on the wick ball, saturating it thoroughly. When the balloon is filled with hot air, carry it away from the fireplace, attach the wick ball to the cross wires, and light it under the supervision of an adult.
In starting the balloon on its flight, take care that it leaves the ground as nearly upright as possible.