Hot Air Balloon (O gauge)
by Charles R. Hentz
xNew for 2018 is a traveling hot air balloon for our O gauge layout that has a simulated flame that lights up for 5 seconds and then off for 9 seconds. This is made from two 8 inch Styrofoam hollow hemispheres purchased at an craft supply store that are glued together. The walls are about 1/2 inch thick. The cone shape was made from poster board and glued to the spheres. Holes were carefully drilled through the center for the wiring. After painting with a base coat of latex paint, Marie Diehl painted this to copy the real Garden Spot Village Balloon. Art Johnsen made the basket with HO scale people.
The balloon is hung from the 1/16 inch aircraft cable of galvanized steel loop that is between two horizontal pulleys that are 24 feet apart. Two additional pulleys are mounted at the center of the span to prevent sag and allow tension adjustment. You may need to tilt one of these upward to prevent the cable from hopping off when the ferrules contact the pulley. We used some silicon sealant to smooth the blunt ends and also increase friction at the drive pulley. The cable is in two sections of steel connected to two six inch sections of nylon cable using ferrules that are crushed. The two insulated nylon sections must be exactly placed at each end. The balloon is hung near one insulated section so that one wire goes to one steel cable and the other wire is attached to the other cable. One end pulley is +12 vdc and the other is negative 12 vdc. Because each cable will alternately contact a pulley of either positive or negative polarity, inside the balloon a diode bridge will provide the correct polarity to two LEDs in series with a 1000 ohm resistor to simulate a flame.
We used a Canakit.com R191A timer circuit board to provide a light that is on for 5 seconds and off for 9 seconds.
The geared 12 vdc drive Nextrox motor is 15 rpm with a 1/4 inch shaft mounted on a uxcell 37mm bracket holder. To this shaft we added a collar with a 1/4 inside hole and with a outside diameter of 1/2 inch so we could attach a standard 3 inch v belt type metal pulley. A DPDT center off toggle switch was used to control the direction.