Disclaimer!
If used carelessly,
this balloon presents a serious fire hazard to surrounding buildings
and vegetation. Proceed only at your own risk. I am not responsible
for any damage inflicted by the use of this design.
Way back when I was growing up in Montana, I
learned from a friend how to build small-scale hot air balloons. It
was great fun to float one up at night with people nearby, and watch
their astonished reactions as they speculated as to the origin of
this strange glowing object. I improved on the design somewhat over
the years, and I still have fun sending them up every once in a
while. Here's what you'll need.
Materials:
1. Make the frame by attaching the strips of balsa
together in a cross shape. I sometimes use thread to lash the balsa
together, then drip a bit of wax on the thread to keep it from
unraveling. Another option is to simply glue the strips together. Do
whatever is easiest and lightest.
2. Attach candles to the
frame. To attach the candles, I just heat the bottom over a flame
for a split second (just long enough for the wax to get soft, but
not liquefy) then press it immediately onto the frame, and hold it
for a couple of seconds. Be careful not to heat the candle too long,
or it will not attach well. There should be 4 candles on each leg of
the frame, for a total of 16 candles. The spacing of the candles is
not critical, just don't get them any closer than two to three
inches from the end, or you will run the risk of burning your bag.
For best performance, I sometimes cut the candles in half before
attaching them. Although this reduces the burning time to about 10
min., it reduces the weight of the balloon considerably, and ensures
good performance.
3. Attach the bag to the frame. This is the
tricky part, and it is good to have a helper who can hold the bag
while you tape the corners. Otherwise, it's very easy to knock the
candles off the frame.
4. Float it! Wait for a cool,
breezeless night. If there is any wind at all, your balloon will
meet a fate like the Hindenberg's. Make sure that you are in a wide
open area with no surrounding trees or buildings. Once the balloon
gains altitude, you wont have any problem, but during the first part
of the flight, the balloon can be a serious fire hazard.
