Thing That Go Boom!  by Rob Bernstein


      This past year's winner of the "Punkin Chunkin" tossed a pumpkin 1,700 yards, or 5,100 feet--at just under one mile, the flying gourd landed only a few feet shy of a nearby highway. Attendees cheered as the pumpkin exploded on contact with the ground, splattering its gooey innards across the asphalt and the sides of passing vehicles.

For the past three years, the townsfolk of Lewes, Del. have been holding the annual competition to see who can launch a pumpkin the greatest distance. Rumor has it that the contest began as a challenge between local farmers who were bragging about how far they could throw an anvil. Inexplicably, the anvil became a pumpkin, and somehow the contest of human power transformed into a battle between huge pressurized cannons, some with barrel extensions of over 100 feet in length. Yes, it's absurd, but it's also infinitely cool.

The pneumatic cannons at the Punkin Chunkin are the grandest, most monstrous of the vegetable- tossing launchers that spud gun enthusiasts have been building for years. And where else would one learn and exchange information about such a device than on the Net?

Constructed from PVC tubing, the ordinary spud gun, or potato cannon, is made from a barrel, a chamber, a screw cap, an igniter and some form of propellant-- usually hair spray. More modern spud guns employ pneumatics (the use of compressed air instead of propellant) to fire off spuds. But as 15- year-old potato gun enthusiast TJ Christiansen explains with terrific hurrah, "You can shoot pretty much any fruit from these things. I've tried putting arrows through the potatoes and shooting those. I shoot toilet paper."

Christiansen, who has been designing his own custom spud guns for years now, says he has learned everything there is to learn about the hobby online: the study of pressures, expanding gases and Newton's Law. What goes up must come down. Christiansen learned this the hard way after he and some friends fired a potato straight into the air. The shot was so powerful that everyone lost sight of the potato. Remembering the unfortunate incident, Christiansen recalls, "We all went running. Not expecting it to come down, it blasted me on the top of the head. I can safely say that that knocked a little sense into me. I don't shoot straight up anymore."

Jim Hammer, 41, a.k.a. Mr. Science, is also a big fan of "things that go boom." At his Web site , Hammer shows off his massive Watermelon Cannon, made from a 12" PVC sail tube, and propelled by cinnamon Glade ("It smells better than hairspray"). When he first fired the gun off in his friend Scott's basement, he was concerned "that the muzzle blast would blow the windows out of Scott's basement." Nevertheless, Hammer says they were "not nearly concerned enough to refrain from firing it." The result: a really big blast and a lot of shrapnel. Approximately six feet of the cannon blew apart into itty-bitty chunks. No one was hurt, but Hammer now focuses his attention on his more tame tomato gun (which recently blasted a hole through his garage door before splattering into tomato paste on the driveway outside).

Hammer also has been conducting experiments with oranges: "We shoot them straight up so we can time them and calibrate our computer models. We think we're getting oranges to 200 feet per second which is like 150 mph. It's fun to watch the orange go way, way up in the air and just hang there." As dangerous as the hobby may sound, the possession and firing of spud guns is legal in most states. A letter from the Department of Alcohol, Tobacco and Firearms, posted on the Net by spud gun hobbyists, explains, "The Bureau has previously examined devices known as 'Spud Guns, Potato Guns or Spudzookas' and have determined that such devices, in and of themselves, are not firearms..." To be considered a firearm, a firing device has to be capable of shooting projectiles over 500 feet per second. But given some of the firepower displayed at the Punkin Chunkin Web site, at the Radical & Extreme Hobbies home page, it might not be too long before some of these cannons fire off projectiles at such high speeds.

It should be noted that some local law enforcement agencies, however, have banned the use or possession of such devices; stories abound on the Net, written by disappointed spud gun lovers who explain that locals who misused the guns (by firing vegetable projectiles from moving vehicles or at one another) have caused unnecessary prohibitions of spud launching.

Despite taking a spud to the head, Christiansen believes the hobby is truly safe. Online enthusiasts agree and have posted dependable spud gun blueprints and precautions to keep newcomers from causing themselves injury. At the Spud Zone, interested visitors are provided with the spud gun code of ethics: Always use alcohol-based propellants; do not fire guns at people, animals or moving vehicles; store the gun in a dry place; and keep the ammo in a separate location (apparently, spudzooka lovers have a sense of humor, too).

In addition to posting blueprints and safety precautions online, spud gun zealots also trade information on gun accessories and different varieties of guns that have been successfully experimented with; at his site, Christiansen details how to attach shoulder straps, sights and scopes, wheels (for big guns), shoulder rests and ram rod holders. The author of the Spud Gun Fuel Experiments Homepage has been posting empirical information regarding different propellant formulas, including variations of methyl hydrate, white gas (camping fuel), alcohol and propane. And Hammer posts descriptions of catapults and chicken guns; "For industrial strength lobbing, it's hard to beat the chicken guns used by most of the major aircraft manufacturers to test windshields and other airplane parts which must stand up to bird strikes," writes Hammer. "I witnessed a test shot recently against a 1-inch-thick aluminum plate. The plate rang like a bell when struck by the chicken, and chicken parts shot 50 to 80 feet into the air."

As intriguing as the chicken gun display may sound, it's widely accepted among spud gunners that the Punkin Chunkin is the big daddy of all such launching sports. There, human powered devices, like catapults, rubberband slings and bicycle- operated centrifugal throwers all make for a good pumpkin mess. The real attractions, of course, are the enormous pneumatic cannons; despite their intricacy, and incredible cost, many cannons fail to work, or only work once before self-destructing in comical fashion. "You have to be a certain person to really enjoy the massiveness of it all," laughs Scott Fichter, author of the Radical & Extreme Hobbies home page. "The power is just so out of control, it's just so out of hand. I brought a couple of friends to see the cannons and they've since lost their minds."

 

 
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