|
This past Friday, a few CR4 bloggers wanted to get into the
spirit of Halloween by launching pumpkins. While "pumpkin chuckin'" is a pretty
popular around this time of year, we decided to put our own twist on it by
using frankd20's drywall catapult as a trebuchet.
 Ready. Aim. Fire!
We began testing the trebuchet by launching water balloons.
Unfortunately, the first run didn't go as well as we'd hoped. Despite the high
levels of excitement from the crowd, the trebuchet repeatedly collapsed – even
leaving a couple of water balloons and a pumpkin relatively unharmed.
Ultimately, after multiple attempts, it was concluded that
the first run at firing the trebuchet was a failure due to lack of research. The
original device was built to lift dry wall, not to be a firing device. Only an
hour or so was spent doing the conversion from a lift mechanism to trebuchet,
which mostly consisted of making the firing release mechanism.
When the crowd had started to assemble that day, we weren't
even completely sure the trebuchet would launch anything. With each collapse,
we lost a few audience members. The problem with the trebuchet was that it
wouldn't let go of the pumpkin at the apex of the swing. Time after time, the
machine would hold on to its projectile and not fire anything.
See videos of the first attempts here.
Back to the Drawing
Board
Despite not having success, we were all pretty entertained
with the attempted launches and eventually returned to work as usual. However,
after just 15 minutes or so, frankd20 figured out the problem and did a quick
fix so that another round of launching could take place.
He determined that the solution was to add a mechanism for
the sling to let go at the apex. This consisted of a metal spike sticking out
of the end of the main beam that one side of the sling, tied into a loop, is loosely
hooked over. As the beam pulls the projectile, it stays hooked until the
projectile is pulled around by centripetal force and is in line with the beam. About
the time the main beam and sling are perpendicular to the ground, it will
release. The centripetal force of the sling pulls the loop off of the main beam,
which releases one side of the sling and let's go of the projectile.
Success!
Once the fix was made, the fun began. The second pumpkin of
the day sailed through the sky and landed with a satisfying thwack, breaking into pieces. We also
experimented with a rotten apple and a small stuffed animal dubbed "Sir
Launch-A-Lot" – both of which flew successfully. The final launch of the day
sent a pumpkin soaring; and as the crowd went wild, the pumpkin ended its
flight with a flurry of seeds and debris. Overall the experiment was a success;
only Sir Launch-A-Lot survived (because he's stuffed) and the rest was smashed
into deer food.
See videos of the successful launch here.
| 
Re: Pumpkin Chuckin’ With CR4
