Sunday, September 29, 2013

Annals of Obsession: Introduction, Trebuchet Design

Recently, finding myself glued to the computer too late at night reading Android developer forums and feeling unable to put the subject down and go to bed even though I knew sleep was way more valuable than what I was doing, I got to thinking about my obsessive streak. I don't think it's extreme, as obsessiveness goes, but it's certainly something that's part of my personality and has an impact on my life.

Then I got to thinking it might be fun to make a chronological list of the things I've gotten caught up in. And even more fun than just a list would be a little synopsis and post-mortem on each. This has been going on for a long time (like "spent most of freshman year of high school on a BBS playing a text MUD, going so far as to learn Basic so I could keep my character gaining experience by running scripts while I was at school"), but working backwards from today I only got as far as...

Trebuchet Design and Construction

Some time in the winter or spring of 2007, a coworker brought the mini trebuchet kit that someone had gotten him for Christmas into the office.  A largish contingent of the programmers proceeded to build it, tweak it, create innovative targets and projectiles for it, and generally have a fun time.  So fun, in fact, that more than one of us started talking about building on a bigger scale.  Since the Punkin Chunkers have made it extremely hard to break new ground on size or power, I was content to set myself the goal of making an effective and fairly elegant water-balloon-scale trebuchet.

After tons of thinking, drawing, and running finely differentiated simulations on trebuchet modeling software (it looks like there are a few more options now than there were then.  I went through one or two before finding one that had all the options I needed and was reasonably usable), I built!

Then I learned some more things, like that the stresses on the cable holding the counterweight were greater than I had expected, and that it's kind of hard to get water balloons to stay in a sling rather than squeeze out the side and burst when they're being whipped around in a really fast arc.

And finally, in the glorious conclusion of the project, at our family Thanksgiving gathering in western Pennsylvania, I learned that I'm not a good skeet shooter.  But between the handful of us, we got a few good hits.  I found it rather magical.

That's my dad pulling.

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