Inspiration
This one came as a suggestion from my friend Clay Johnson who is a veteran of many spud launcher campaigns. There are oodles of plans and models out there for the picking, I went with a straight forward combustion based mid size plan for our first attempt. I was also feeling guilty for missing a weekend due to work, and wanted to something extra exciting to make it up to the girls.
Materials
1 x 4" PVC T joint - combustion chamber
2 x 4" PVC screw on cap pairs - one for the igniter trigger and one for access to add fuel.
4" - 3" PVC adapter - barrel (inside tip filed somewhat sharp to help cut and compress the potatoes)
4' x 3" PVC pipe - connector fro barrel to chamber
4' x 1.5 PVC pipe - rammer to push potatoes to about a hand width away from the combustion chamber
1 gas grill replacement igniter - trigger mechanism and ignition source
1 can of Aquanet hair spray - fuel (about 2-3 seconds is plenty for this size chamber)
1 bag of yukon gold potatoes - ammunition
1 rubber mallet - to jam and trim the shot in to the barrel.
Notes
This was a fun project to find supplies for and build and probably our most carefully planned event to date. I looked up various plans and possible legal issues as well as I could (eventually confirming with a local police officer that we wouldn't get in trouble for this so long as we were safe with it). We found a nice big abandoned field nearby for the proving grounds as well. Assembly was easy and with a hand saw and drill for the igniter (which I stripped down to its base components before fixing to an end cap). I was also glad to do test fires with the bare igniter in the closet with the girls to explain how that worked, along with dry runs with an open chamber and hair spray so we could test the fuel and ignition combo, and so the girls could see the flames involved in the combustion. We had previously talked about hot air expanding with a few other experiments so they had a good grounding in the physics involved. The results were spectacular to say the least, launching spuds between 100 and 150 years with ease. We turned the actual launching in to a drummer hoff like event letting them each play different parts. Eventually with some refinements we've gotten the cannon to send them over 190 yards.
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| Here I am doing my best Corporal Ferrel. |
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| Lana aka Major Scott bringing the shot. |
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| Sargent Chowder bringing the powder (or Aquanet in this case). |
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| Lana pounding the first shot down the barrel. |
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| Noelle doing her best Captain Bammer as she rams the shot in to position. |
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| Noelle and Lana going out in search of the evidence. |
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