Date: Tue, 20 Jan 1998 00:06:50 -0800
From: Johnny <johnny@johnny-enterprises.com>
Newsgroups: rec.aviation.homebuilt
Subject: Re: Anybody ever gotten a Model Hot Air Balloon to fly?

Yet another route, all though not really a balloon, is the road flare
and parachute method. This is a great one at night because you can see
the flare literally for miles, and it will get really good altitude and
range because of the extended flight time and excessive heat. I've heard
of them being able to go from one end of Seattle to the other, if the
wind was just right.

Method of attachment varied, but usually it consisted of a ring of some
sort to keep the strings for the parachute on an outside perimeter to
the flare. The flare was supported vertically inside the ring. Parachute
canopy was typically 3-6 feet in diameter. The string length was one of
the key factors to let the canopy capture the heat, without getting so
hot that it would burn. The mysterious flight path and glow of the units
were told to have prompted more than one UFO report. Loads of fun for
bored kids. This was before we had the Young Eagles program of course.
;)

-j-


Ronald James Wanttaja wrote:

> In article <69tqbt$bho$1@news.xmission.com>, wdonohoo@xmission.com (Walter
> Donohoo) wrote:
> >
> > I have heard of people building small Hot Air Balloons using just a
> > birthday candle to heat the air. Does anyone know the procedure for
> > doing this? I built one out of a small, mylar like,  garbage bag taped
> > to a portion of an aluminum pop can to hold the candle and could not
> > get the air in the bag hot enough to provide lift inside my house or
> > outside. I also tried filling the bag with hot air from my hairdryer
> > first to fill it up and then attached the candle, still no luck. Is
> > there some secret to getting the air hot enough to get the bag to
> > rise?
>
> I used to do this a bunch back in my younger days.  I see three major
> problems with your approach:
>
> 1.  Use of a garbage bag for an envelope.  Too heavy
> 2.  Use of a pop can to hold the candle.  Too heavy.
> 3.  Use of a birthday candle for a heat source.  Too heavy, not enough
> heat.
>
> Solution:
>
> Use a clear plastic dry-cleaner bag, the kind that clothes come back
> from the cleaners in.  Use scotch tape to seal the holes in the top, and
> cut off any extra plastic beyond the "seal line."
>
> To hold the big end open, make a set of cross-braces out of thin balsa
> sticks.  Something ~1/8" square, or maybe even less.  Glue them into an
> "X", or get out the scotch tape again.
>
> We used to get hexamine fire-starter tablets at the surplus store
> for our heat source.  Use two, they're each about the size of two
> Life-Savers.  Alternatively, use a dollop of Sterno.  To hold the Sterno
> or fire-tablets, make a holder out of aluminum foil.  Cut out a ~2.5"
> square and fold up the edges to make a little tray.  Scotch-tape it to
> the cross-pieces.
>
> I actually have heard that they'll fly with a birthday candle.  My
> suggestion for that is to cut the candle into four equal lengths and
> tape them to the crosspieces (no tray necessary).  Light 'em all, and
> you've got four times the heat (at 1/4 the total burn time, of course).
>
> The key is lightness, lightness, lightness.  One little factoid sticking
> in the back of my mind is that the air in the balloon must about ~100
> degrees hotter than the ambient air to generate any appreciable lift.
> Obviously, a cool night is best.
>
> Back in North Dakota on a -20 degree winter's night, we used to be able
> to get tons of lift.  We bought some dethermalizer fuse from the hobby
> shop, and would load up a couple of firecrackers and bottle rockets.
> We'd start the balloon fire, wait until we got positive lift (BTW, it
> takes a bit of work to keep the plastic bag away from the fire until the
> bag inflates), then light the DT fuse and let 'er go.  With presence of
> mind, one could even do the old "One thousand, two thousand" routine
> when the firecrackers flashed to determine the approximate range.
>
> We started no range fires...that we knew of.
>
> Ron Wanttaja
> wanttaja@halcyon.com
> http://www.halcyon.com/wanttaja/