Atlatl!

[corivax]

I was playing with gfish's atlatl (a gift from the wondrous keen vixyish), and it is neat. I will now proceed to gush about it. :)

Comments

[iridium]

ooooh neat neat neat neat!

*smile* that is all. 's too late at night for anything more coherent.

[bkleber]

I haven't heard about an atlatl since 7th grade history when my teacher was sharing the above-referenced in-and-out-of-armor-on-a-tree-stump story, and he did such an awful job of explaining how it worked that it never really made sense to me.

The harmonics of the flex wave traveling on the spear, though, is fantastic. Thanks for sharing! Now I want to try...

[corivax]

Depending on your age, we might not have known how they worked yet. An enterprising engineering student named Bob Perkins was the guy who figured out that using a flexible dart quadrupled range and power, and he didn't work it out until the eighties sometime.

If you happen to find yourself in Seattle, look myself or gfish up; I'm sure he'd let you fool around with his.

[dilletante]

interesting. on atlatl.com, mr perkins talks about the mechanics of the atlatl in such vague and mystical terms that if i hadn't been referred to him by you i would suspect he was making it all up. "the number pi is found for optimum performance in the Relationship between Atlatl length and dart length"?

[corivax]

Many of Perkin's ideas are generally accepted at this point. Others are still debated by people like Dick Baugh, another engineer-turned-atlatl-maker, who's done some interesting computer modeling. My objection to Baugh's computer modeling, as I understand it, is that he tends to model absolutely perfect throws on the human's part, and I think it'd be folly to design a weapon assuming that.

I don't know if the ideal ratio is pi (though I like to think it is), but it does seem to be very near 3.1.

Perkins has some papers that are much more interesting than his 'give me lots of money for a mysterious magical atlatl' website.

[sunspiral]

What a great explanation! I'd never known that an atlatl was anything more than a lever arm.

[dilletante]

yeah, me neither. neat!

does this make the exact length and stiffness of the dart fairly important, or can you learn to adjust your throw for them a bit?

[corivax]

Yes, construction has to be fairly exact. The dart:atlatl length ratio is, ideally, pi, which just fills me with glee. :)

The springiness of the atlatl itself, important for reflecting the wave once, is tuned with by the weight of the stone tied onto it.

[corivax]

Erk. That should be "less than a tenth an ounce's weight".

[twoeleven]

yay! ancient weapons and traveling waves. these are a few of my fav-or-ite things! (i'll be good and won't sing.)

This is incredibly spooky the first time it happens, I assure you. One wishes to grab the universe by its lapels, shake it a bit, and demand one's regular physics back.
hee! well put.

unfortunately many ancient weapons make good can openers. i've read a charming story of a different flavor of javelin that had a bad tendency to pierce both shield and armor, and pin guys to ground while they were standing upright. :P

[larksdream]

Wow, that's amazing. I feel the glee of new knowledge. :)