Monday, January 11, 2010

Cannon Fodder - Applied Science

After reading A Brief History and Building a Cannon you should know that there is only one thing left to do. Actually use it. Well, I needed a fuse, and it turns out that the hobby shop doesn't sell the regular fuses anymore. They only have the electronic kind. I did find some online through a fireworks warehouse. You got to love the internet. You can buy anything online.

To begin the tests, I had to make certain that I wasn't going to blow myself up (a rather important step if you want to continue to have fun with cannons). I had built two combustion chambers (since I had two tubes of PVC), although I only assembled one in a cannon. The other was for cannon testing.

Over the course of a couple of evenings, I made some small fireworks displays in the backyard. I started with relatively little black powder (about a half a teaspoon) to see how much of a flame/ smoke it would create. I slowly built it up until I was igniting a full tablespoon of black powder. Then I tried it by covering the combustion chamber with a #10 can. Everything worked. And suprisingly, the neighbor kids either didn't notice that I was making big clouds of fire and smoke, or just didn't care.

My first thought was to test this out on Thanksgiving weekend. I was going to be down at my brother's place where there was plenty of open land. However, a combination of deer season (cannons tend to scare away deer, or so I've heard, I'm not a hunter and couldn't care less) and a broken fridge (he lives an hour from town and having a fridge die during a weekend when all of the family is in town is not fun) nixed the testing of the cannon. So it would have to wait until I had another opportunity.

That opportunity came on New Year's Day. What better way to ring in the new year than by firing off a home made cannon. I asked my wife if I could go test it in the afternoon and she consented. I figured that the cold weather (-5 degrees) and holiday would keep people away from the range. I didn't want anyone around in case something bad (like an explosion) happened. While I had tested out the combustion chamber in the backyard, this would be the first live test of the cannon.

For some crazy reason, there were actually half a dozen people at the shooting range. (Don't they know that it is freezing outside!) So I continued on driving down the road to the Shotgun range. I was sure no one would be dumb enough to be out shooting clays in this weather. I was right!

After setting up, I loaded the cannon with a half a tablespoon of black powder. For my shell (cannon ball), I used an empty can of peaches wound with duck tape to the same diameter as the barrel. So, for the first shot, it would be a very small charge, shooting out a very light (and non aerodynamic) shell. It took forever to light the fuse since the wind kept blowing the matches out. Finally, I saw the sizzle of the fuse, and ran back about 50 feet. While I wasn't expecting any negative consequences, I wasn't going to tempt the firearm gods.

Pfft! It sounded just like a 4th of July mortar firework. (Which makes perfect sense since it is basically the exact same thing minus the dazzling display of colors in the sky). The can flew out about 20 feet in the air and 10 yards down range. A big smile broke across my face. I had just built a working cannon with stuff you can get from a hardware store. Now, the fun was about to begin.

Just before Christmas, my kids cleaned out the basement and ended up with two trashbags full of stuffed animals that were not needed. Goodwill won't take them and I was thinking of sending them to fellow blogger JayG who loves to bayonet stuffed animals. But then I got a better idea. If bayoneting stuffed animals is an acceptable practice in the communist state of Massachusetts, then shooting them out of a cannon must be an acceptable practice in the slightly more free (we are still a May Issue state) land of Iowa!

So little teddy bear got to be the pioneering cannonaut! I used a full tablespoon of black powder and just stuffed the bear in the can. Pfft! A little louder this time and the teddy bear went sailing. About 20 yards. Not bad. One of the most satisfying things about a black powder cannon compared to an air cannon or even a flammable fluid cannon is the big puff of smoke. The wind was blowing perpendicular to the range of fire so after each shot there would be a nice 5-10 foot smoke cloud floating away.

A third time with a tablespoon and a half and a fourth time with two tablespoons. The teddy bear did not disappoint, each time going a little farther, until he peaked out at around 30 yards. I did notice that the can was going farther, about 40 yards. So, by my eighth shot I was practically frozen, the wind was blowing and the wind chill was about -30 (no, I am not exaggerating) and since I had to take off my gloves to light the fuse, my hands were numb.

I decided that my eight shot would be the final one for the day. I wanted to get some weight to the shell so that it would have more momentum (also less air resistance as I would fill up the can. At first I thought of packing the can with snow, but decided that it wouldn't really add that much weight, snow just doesn't weigh very much. While I was retrieving the can from the range, it hit me. I'm on a shotgun range and there are bound to be clays I could crush up into the can.

Sure enough, the people who use the shotgun range are about as good of a shot at flying clays as I am (which means not good at all!). In no time I had found a half dozen unbroken clays. I smashed them up into the can. Now it had some weight to it.

Three tablespoons of black powder in the chamber, then the can and the teddybear on top for good measure. I set the camera to continuous picture to be able to get multiple shots.

Pfft! Somehow my camera was timed perfectly to not only capture the teddybear in the early stages of flight but also the growing smoke cloud AND the two foot column of flame.

The teddy bear did a perfect spread eagle at the apex of his flight and traveled about 35 yards. The can continued on to about 65 yards.

I was giddy all the way home. In my mind I started planning what types of shells I am going to make and different combinations of powders to use. This was only a two foot cannon with a combustion chamber that is large enough for about a half cup of black powder (six or so table spoons). I think for the three foot cannon I'll make a combustion chamber that is twice that size. If anyone would like be to give a demonstration and a physics lesson to elementary, middle, or high school age kids, I'm ready. You can bet that the 4th of July will be a whole lot of fun at the Reputo Casa!


  1. You are CRAZY! I would be so worried about what other people were thinking I was trying to do I probably wouldn't experiment like you did. That looks like it was a blast!

  2. This is quite possibly the most awesome thing I will read today...

    I am honored to be the inspiration... :)

  3. Thanks for the complement JayG. If it weren't for you, those stuffed animals would have found a dumpster in no time flat. Now, me and my kids can feel good that we are putting the worn out toys to another use. Its like recycling only with a satisfying BOOM and a puff of smoke!