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Hydroaeropropulsion Rocket Research Labs
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5 september 2002
A new toy ... erh ... piece of scientific equipment: a 2 liter bottle!
Four metal plates make a little device you can use to push corks
into bottles. Pushing the bottle itself is not a good idea: the 2 liter
bottles are not as strong as the 1.5 liter ones and get bent when you
push a little too hard.
This one did not fly extraordinarily high, alas. Still not bad, but we'd
expected more from a bigger bottle.
The second launch was higher and fulfilled our expectations better,
except that it ended in a tree. We'll try to recover that bottle
some later day ... so no more 2 liter launches for today.
Look, visitors, interested in science and technology!
This time, the 1.5 liter bottle will be launched.
We try the 1.5 liter bottle with parachute, just like we did yesterday.
Alas, the parachute detached from the bottle!
The cords were clearly
not connected well enough to the bottle (we used two (too) short pieces
of yellow duct tape).
Second attempt, this time with a 1.5 liter coke bottle. Because this
bottle is a little wider, I made four cuts in the bottle cap so it could
more or less fit atop the coke bottle.
Alas, this one suffered from the same disease: the parachute detached
from the bottle in full flight and both pieces landed separately.
The problem seems to be that the cap comes loose when the bottle
is still at reasonable speed. Then, the bottle pulls the whole
parachute construction with considerable force (since it still has good speed),
which the duct tape could not withstand.
Launching went a little problematic today. Often, you had to pull
really hard at the rope before the nails would move; sometimes
the whole launch pad was pulled instead of only the nails.
And when the nails finally shoot out, they frequently fly loose from
the rope, disappearing somewhere in the grass (we lost 4 of them today).
So I plan to paint some nails bright yellow and use those; hopefully
we'll spot them better in the grass ...
