Physics of a Spudgun :: physics potato gun cannon

Well it's quite simple actually. Spudguns use some of the same principles as internal combustion engines. Just as burning gas forces a piston out of a cylinder it can also force out a potato. A spudgun is a device that uses some form of propellant to project a potato across the sky. Usually these devices are made of ABS plastic sewer pipe. There are several major parts of the spud gun that these pages will refer to. These parts are the firing chamber, the igniter, and the barrel. The ignition device of a spud gun is simply put the spark generator that causes the combustion of the fuel in the firing chamber. This device is usually a charcoal grill lighter. The button on the sparker is depressed and a spark arcs across a wire lead and a ground wire. The grill sparker is installed in to the back of the firing chamber by means of threading, epoxy, and bolts. This sparker becomes a projectile if it is not well seated in the end cap of the firing chamber. It must be held firmly in place withstanding any pressure produced by the fuels being burned in the chamber. This type or igniter will work in most conditions including when it becomes wet with fuel. Other igniters exist but are not recommended as highly as the charcoal grill sparker. The Colmen lantern spin lighter which use a flint and striker can become gummed up with some fuels and is not recommended for use in spud guns which will use hairspray as a primary fuel. This lighter must have new flints installed when they run out. This type of lighter also will fail to function when wet with fuel. The flame style barbecue lighter is a click lighter that produces a small-sustained flame. This lighter rarely misfires but is very hard to install given the high pressures it would be subjected to. Also the fuel in the lighter it self must be refilled. Some Spud Guns use a spark plug and battery setup that involves more work as well as more components. The benefits of this style of ignition system is that you have the ability to remote detonate the fuel from a safe distance. By far the push button charcoal grill sparker is the recommended igniter. It is cheap, effective, relatively easy to install and long lasting.