Indoor Hot-Air Ballooning at TEP
A not-quite-typical Saturday evening at TEP
So it was Saturday night, and a bunch of us were sitting around, doing
nothing, just sort of flaming away, with nothing in particular to do.
Somehow the conversation got twisted over to talking about how somebody
had heard about how you could fill up garbage bags with hot air by
placing them over a stove with the burners on. Being, of course, bored,
Schmooz immediately leapt up
and went downstairs to grab a garbage bag and try this. I trailed along
behind, just out of curiosity as to whether it would work or not. We
grabbed a couple garbage bags, went back to the upstairs kitchen, and
turned on all the burners there, and held the bag over it. After a
while of filling, we let go, and the balloon floated to the ceiling.
Whee.
This was not nearly as exciting as we thought it would be. Then Schmooz
came up with the idea that we should try to float it up the center
stairwell of TEP. So we filled up a garbage bag again with hot air, and
then ran over to the center stairwell with it, and let it go, where it
rose about 2 feet and then collapsed because the air had cooled enough
that it didn't have much lift anymore. This was a big disappointment.
Somebody sighed: "If only we had the stove in the center stairwell..."
You could see Schmooz's eyes light up, as he said, "I have it!" and ran
away again.
He came back in a minute from downstairs holding a propane torch. We
all groaned, as we realized his "great" idea. He pooh-poohed our
caution and said, "We have a fire extinguisher right here! what's the
worry!" So we tried it again - this time, filling up the garbage bag in
the center stairwell itself with the propane torch, and somebody
wielding the fire extinguisher right there just in case. This worked
much better - the air was hotter, and we could release it immediately.
Unfortunately, the bag kept on drifting off to one side or the other as
it floated up the center stairwell.
The new goal of the night had become to create a hot-air balloon that
would make it up all 5 stories of the center stairwell and hit the
woodwork at the top. The first problem - the balloon kept on drifting
off and hitting the sides of the stairwell. The answer? Stabilize the
garbage bags by attaching weights to the sides of it. We fiddled about
trying to do this for a while, until somebody hit on the notion of
taping string to each side, and then tying all the string together in
the middle, where we would dangle paper clips from it. This seemed to
work quite well, and the question then became how many paper clips was a
good compromise between stabilization and too much weight on the
balloon.
Meanwhile...
Meanwhile, also in the center
room, Brad had a new toy to play with - a
blowpipe that he had just bought. This blowpipe came with several darts
which were basically just pieces of wire with beads on the end to make
them fit in the pipe. So of course we started trying to hit targets
with it. We started with simple stuff - hit the Purple board. Then
we got more advanced, trying to hit specific targets on the Purple
board. Somehow, some stupid person came up with the idea of trying to
puncture cans with the blowgun darts. So we started setting up cans and
seeing if we could get the dart to puncture through both sides of the
can, for instance. This was quite amusing, and everybody wanted to take
their turn.
Back with the ballooners
Back with the ballooners, it was quickly discovered that the optimum
number of paper clips was around 3-4. We also discovered during this
period that we had to be careful when filling the garbage bags to keep
the heat away from the sides of the bag and far away from the top,
otherwise the plastic started to melt and that was quite a mess. But we
still had the fire extinguisher on hand in case things went wrong, and
we were being relatively safe - at least by TEP standards. The other
tricky part was now getting the torch in and out from between the
strings holding the paper clips, without lighting the string on fire,
the bag on fire, or the people holding the bag on fire. This required
great delicacy and lots of advice from all quarters.
After a few more runs, we realized that one garbage could not hold
enough hot air to make it all the way up the center stairwell, even if
it didn't hit the sides. It would get up to about the third floor, and
just run out of gas (so to speak), and start floating back down slowly.
But we remained firm in our purpose, that we would get a
garbage bag balloon to hit the top of our center stairwell.
So since we didn't have enough hot air in one bag, we decided to try 2.
We cut 2 bags apart into sheets of plastic, and then taped them together
carefully. After attaching the strings and paper clips again, we
inflated it and let it fly. It just SCREAMED up the center stairwell
going up like a rocket and hit the woodwork at the top hard! It was
amazing to watch and vastly satisfying to have achieved our impromptu
goal for the night.
What would you say if...?
What some of us knew, but none of us remembered was that this was the
night that Deb had offered our front room as a crashing spot for
several
of his friends from SEDS that evening. So imagine this group of people
walking in the door with Deb in the lead and seeing the center room of
TEP at this point. Picture this - there are several
people playing with a blowpipe, and putting little darts through
aluminum cans at high velocity. Right next to this group are another
group of people, one of whom is holding a propane torch underneath a
LARGE garbage bag (actually two garbage bags taped together but we're
describing what you see at a glance here), which has string dangling
down from it. There is somebody standing nearby with a fire
extinguisher at their side, and lots of people sitting around flaming
about what's going on. Now, wouldn't you be scared if you had
to spend the night in a place like this?
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Eric Nehrlich's WWW home page / nehrlich@alum.mit.edu