Friday, October 06, 2006

Be Careful What You Ask For

While in Virginia, we visited my cousin who is restoring some of our antiques. He showed us the pieces. We discussed some of the particular issues with flooded furniture. Then the conversation took a turn towards his true passion, Civil War-era cannons. Some of you have foolishly asked to hear more about this. I warned you not to, but you're the boss, so here goes:

When he was a kid he had been incredibly bored in school, and the teacher had sent him to the corner to read reference books, and he had seen a picture of an old cannon and fallen in love with it, and later on, he had trained as an engineer but decided it wasn't for him and had taken up cabinetry and furniture restoration, and in his free time, he now built third or half scale, fully functional replicas of Civil War-era cannons, and he had acquired copies of the diagrams drawn by the original Union engineer who designed the cannons, and as it happens, they're almost exactly one-third scale though he'd had to rescan and slightly alter the size to get an exact match, and although the diagrams existed there was no explanation for why they were designed that way, and he had wanted to understand why, so he was building replicas, and look at that picture - isn't that just the sexiest thing - and here's one of the spokes of the wheel which as you can see is not precisely vertical but is actually at a three and a half degree angle from the hub, which presented a special technical challenge to manufacture, and he spent days trying to duplicate them with little success until he researched the historical methods and learned the appropriate techniques, which were much more effective, although each spoke still takes one and three quarters hours to make because he hand whittles the tapered form, and he showed me a box full of spokes which represented weeks of work, and the reason for the three and a half degree outward radiating angle is that without it, as the wagon traveled over rough terrain, the axle would move laterally and just bust sideways through the wheel, but with the angle, the force is radiated out along the spokes and into the metal-bound rim, which contains it, but this presents another challenge because if the spokes are at a three and a half degree angle, they no longer maintain an optimal vertical load-bearing configuration, so the ends of the axles are actually tapered slightly and the wheel actually slopes outward at a slight angle, and the bottom spokes are oriented perpendicular to the ground while the top spokes are actually at a seven degree angle to the ground, so that if you actually saw one of these wagons from the front you would see the wheels angling out slightly in a v-form, and the cannon is hitched the front wheels, the "limber", with a single joint so the wheels are fully articulated and travel over the rough terrain - because there were very few good roads at the time, there was one over in the Shenandoah valley - without structural damage, and the limber of the cannon carried a metal-wrapped box with shot and gunpowder, and duplicating this presented additional technical challenges, because at one third scale, all the nails will actually split the grain of the wood so he had to drill one hole into the wood slightly smaller than the head of the nail and one whole into the copper slightly larger than the head of the nail, and of course, each box has dozens of nails, and each cannon had several auxiliary wagons travelling with it, carrying supplies and whatnot, and there were several cannons with each unit, and each unit also had a special forge-wagon, and of course, the limber for the forge wagon carried forge supplies, not cannon supplies, and there were special wagons specifically designed for the retrieval and transport of cannon barrels seized from enemy, which were considered important trophies, and the Union had one really genius engineer who designed this curious looking cannon with a bulbous back end that went something like this, and the brilliant thing about this cannon was that the curve of the barrel precisely represents the time/pressure curve as the cannonball travels the length of the barrel where X is time and Y is pressure inside the cannon, so the thickness of the cannon wall and the pressure is perfectly proportional at every point, and...

That'll do for now. Will pick up where we left off tomorrow.

7 comments:

  1. and the Union had one really genius engineer who designed this curious looking cannon with a bulbous back end that went something like this, and the brilliant thing about this cannon was that the curve of the barrel...

    Oooh oooh! Oooh! I know! Is it... Dahlgren?

    Great stuff :)

    ReplyDelete
  2. ROFLMAO! I love this! And it's gotta be the longest run-on sentence evber, right? Good show!

    ReplyDelete
  3. Now Slimbolala, did your cousin really say all that or were you being a bit creative and expansive?

    ReplyDelete
  4. Amazin!

    I await with bait on my breath for more.

    ReplyDelete
  5. Not the least bit creative and expansive. He said every darn bit of it, and I've even omitted a fair bit. For example, do you know how the size of the wheel was determined? The height of the horse. The most efficient wheel size is the one where the center of the wheel is at precisely the same height as where the harness attaches to the horse (though as the war progressed, the average size of the draft horses increased somewhat, so later in the war the axes were often slightly lower than the harness point).

    ReplyDelete
  6. Could we somehow make a recording of your cousin reciting this riff accompanied by Ornette Coleman?

    ReplyDelete
  7. Oh, I forgot to mention, Ornette Coleman actually was there, playing in the background...

    ReplyDelete