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Hydroaeropropulsion Rocket Research Labs
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6 september 2002
More wind today than yesterday, so we decided not to try parachute launches
today because they would probably end up too far away from the launching site.
We added a little bicycle pump tube between our pump and the cork to ensure a
better fit to the valve. On the picture is a 1.5 liter bottle.
Notice the upgrades to the launcher: larger L-pieces, thicker threaded
rods, wing nuts.
A close-up view of the launching system.
Next, a 2 liter bottle.
Alas, the 0.5 liter bottle does not seem to fancy a flight.
One of the nails shot out but the other one refused. The bottle
depressurized slowly and then we could remove everything safely
from the launching platform.
Probable cause: as you can see here, the left wing nut is positioned
a lot higher than the right one.
This is the 0.5 liter bottle again, about 0.2 seconds before start of the flight.
This time, everything went fine except that I wanted to get a picture
of that bottle about 0.2 seconds after the launch.
It's not easy to press the photograph button at the right time;
next time better luck ...
An 1.5 liter bottle just after launch.
The bottle itself is not visible on the picture (it's somewhere far up);
the 0.5 liter bottle you see
on top of our water reservoir has nothing to do with the launch,
it ended up there by coincidence, just in case you'd wonder.
We put the water reservoir on the launch pad to avoid the situation
that when pulling the rope, the nails do nothing and the whole launch
pad starts sliding over the grass. Next time, our photographer will
try to find a better angle.
We also had some trouble with the cork not sealing the bottles completely;
sometimes we could only manage to get 2 bar of pressure inside the bottle.
Probably the cork is at the end of its lifetime and needs replacement.
On the plus side, we didn't lose a single nail any more. As an extra
precaution, I had taped some yellow duct wire to the nails but it would
not have been necesarry for today.
