Today is a momentous day in the life of the Trebuchette. Today is the day when we unveil the new main arm design. We call it the Explorer Arm.

Now, I gotta be honest and say that most of the fun of trebuchets is playing with them. And a lot of that fun for me is being able to tweak the design slightly here and there and see how my modifications affect the launch.

Our existing main arm design, while optimized for flinging superballs and pennies, wasn't very tweakable. Now we've fixed that. The Explorer Arm (which will be coming standard on all of our trebuchets) gives you the ability to change several variables—the counterweight basket axle location, the main axle location, and the firing pin angle—and see how they affect the launch. The new range of options should also let you optimize your trebuchet for firing a wider range of projectiles. For example, while the standard arms are great for pennies and small superballs, they have a hard time with more massive objects. With the explorer arm, you can just bend the firing pin forward a little more in order to ensure that your new, larger ammunition flies forward as well as the small pieces did, and not backwards, or straight up, as sometimes happens.

Enough of the words now, it's time for some photos!

There's three pictures I've uploaded below. The first one is an overview of the new arm piece, and the second one is a closeup of the multiple holes available for the counterweight basket axle and the main axle. Those are pretty self-explanatory. But the third photo is magic.

On the third photo, you can see a close-up of the new firing pin. We're now using 12 gauge copper wire for the firing pin, rather than just cutting the pin out of the plywood with the rest of the arm. The 12 gauge wire is just stiff enough to hold its form without any trouble while undergoing all of the forces during a launch, while being thin enough to be easily bent to a new angle by hand or with a small pair of pliers. The slot it's being held in is also very carefully engineered. We went through more than a dozen prototypes in order to get the slot spacing and sawtooth design (the little bumps you see are a special one-way sawtooth design that lets you slide the copper firing pin into place and then holds it securely against slipping out) just right. The result is a completely adjustable main arm, for all your sieging needs.