Tuesday, November 08, 2011

American Pumpkin Chuckers


American Pumpkin Chuckers
by Mark Luedtke

Shows about Medieval knights and battles are popular shows on the History Channel. Renaissance festivals have become a modern American tradition. Americans love the romance of the Medieval period. Many dream of donning armor, riding a fine stallion, defeating the dark knight and saving the damsel in distress.

But engineers are a little different. They prefer to build and smash things. When they watch the History Channel, they wonder about the great siege engines of the period. That wonder motivated a local band of engineers to compete in the trebuchet division of the World Punkin Chunkin Championship.

The Trebuchet

The trebuchet is the most devastating catapult of the Medieval age. A trebuchet is basically a gigantic staff sling attached by an axle to a frame. The original models built in fifth century China were powered by humans pulling the short end of the staff to rotate the arm and throw a 250 lb weight a couple hundred feet. By the twelfth century, engineers had created much larger machines powered by counterweights that could hurl a 200 lb weight 1,000 feet. But after the invention of cannon, trebuchets were reduced to historic curiosity.

Then in 1986 John Ellsworth, Trey Melson, Bill Thompson and Donald Pepper challenged each other. The World Championship Punkin Chunkin website recalls the history, “‘It all started back in 1986,’ said Ellsworth. ‘We were playing around one day and somebody started talking about throwing pumpkins. There had been an article in a newspaper or on television about some people throwing pumpkins at Salisbury State. A physics class or something. One of us said that they could throw farther than someone else, and I threw my hat on the ground.’” The rest took up the challenge, and an event was launched.

To illustrate how far it’s come since, Melson’s winning chunk that year was 126 feet. The contest now has 13 categories, and the record toss excluding air guns was set in 2008 in the adult torsion category at 3091.78 feet. That’s well over half a mile. Air cannons fire pumpkins over a mile. The event includes a pageant, a chili cook-off and a pumpkin cooking contest. The World Punkin Chunkin Championship is simulcast on the Science and Discovery channels on Thanksgiving Day. Last year’s episode is the highest rated show in the history of the Science Channel.

The event has become so popular that engineers have developed modern designs and employed modern materials to throw pumpkins farther. One major design improvement, called a floating arm trebuchet, replaced the trebuchet axle with an arm that floats on wheels and allows the counterweight to fall perfectly vertically, imparting maximum energy to the pumpkin.

American Chucker

In 2004 Patrick Imlay, Don Poe, Ken Nairn and Eric Puschmann entered the inaugural CFC Pumpkin Chuck. Their website tells the story, “The first machine we built back in 2004 was made of used deck boards from a team member’s back yard. 'Chucky' threw 252 feet in a charity event in Dayton Ohio that was sponsored by the engineering department at Wright Patterson AFB. It was a very limited version of Yankee Siege design that broke on about the second throw, but we were hooked.” Hooked is an understatement.

In 2005 the team switched to a floating arm design made from wood, steel, aluminum and PVC. Rumors that it included a paper clip and gum wrapper cannot be confirmed. Each year they improved that design, replacing wood with steel to improve their performance.

By 2009 they were confident they could compete in the world championships. “We really beefed up for the 2009 WCPCA event. Our machine came off the ground and up on the trailer. Our arm was extended from 13 feet to 16 feet. The vertical supports went from 16 feet to 24 feet above the ground, although the drop is only 12 feet down to the wheel rails. The pivot between the arm and weight bar was strengthened so we could handle 2000 pounds. We launched our November 8 pumpkin with about 2250 pounds, and to be honest, we all paid homage to the Great Pumpkin, had our fingers crossed and hoped we wouldn’t break the machine.”

Once they decided to go to the world championships, they had to overcome a new hurdle: finding a new name. “We went to a series of ‘Chucky’ names, ‘Son of Chucky’, ‘Chucky Two’, etc, but when we started looking at the WCPCA, we found out that name was already taken, so in a serious team meeting at Hooters, over several pitchers of beer and a lot of painfully hot wings, we came up with American Chucker. In retrospect, I guess we're all happy with the name now.” Happy or not, it stuck. They earned second place out of 18 other trebuchets with a throw of 1885.99 feet.

Brimming with confidence, the engineers made some changes to American Chucker hoping for a win in 2010, but it was not to be. “We tried to beat our best throw from last year (1886 feet) by adding more weight and height, but ultimately failed. First we threw a 'safe' shot of 1783 feet Friday afternoon. Then during a Saturday morning open range test shot, the tip of our throwing arm struck the left upright. With help from other teams, we fixed the damage we could see before our afternoon shot.” But a spectacular failure proved the damage was worse than they realized. “The arm had internal damage which caused it to break and launch down range that afternoon. That shot made all the highlight reels, and we started gathering materials and tools for a major repair before the last shot Sunday afternoon.”

Other team members and local residents scrambled to assist. A local machine shop, closed on Sunday, opened to help them machine a brace to repair the broken arm. A participant welded the pieces back together so they could mount the arm and get off the final shot on Sunday. Even though the final throw wasn’t competitive. All the team members point to that project as an example of the camaraderie of the participants. Despite the setback, American Chucker still earned third place because of its first throw of 1780.75 feet.

2011

Team American Chucker includes four more team members now: James Connell, Steve Beyer, Tim Slifcak and Pete Hendricks. They converted Mr. Slifcak’s gigantic barn into a machine shop and began upgrading the trebuchet for 2011. The red metal barn with acres of farmland behind it provides a perfect work and test environment. The major upgrade this year was replacing the heavy steel arm with a significantly lighter aluminum arm. According to team captain, Patrick Imlay, they were expecting a 10 to 15 percent increase in distance because of the arm.

The American Chucker trebuchet is an impressive site on the field. At the 8th Annual CFC Pumpkin Chuck at Wright Patterson AFB National Museum, a charity event for the Combined Federal Campaign, held October 14th, American Chucker towered over the other five entries. When the machine throws, it’s even more impressive.

Pumpkin throwing contests require contestants use pumpkins weighing between 8 and 10 pounds. Because powerful machines like American Chucker exert so much force on the pumpkin, only special breeds are used so the acceleration doesn’t smash them in the sling. The team wouldn’t reveal the breed of pumpkin it uses. It’s a trade secret. For the first throw at the CFC event, the team hoisted 2,050 pounds for a drop of nearly twenty feet - that’s like dropping a small car off a two story building - to throw a 10 pound pumpkin. It launched the pumpkin with such speed it was nearly impossible to see and with a crack that sounded like a jet breaking the sound barrier. The throw went so far that the pumpkin nearly landed in the road almost half a mile away. The organizers should consider moving the machines farther back next year.

But for all the fun these guys have, there’s also frustration. The force of that first throw snapped their new aluminum arm into pieces. They lost about 15 man hours putting it on and another six replacing it. Mr. Nairn describes the frustration, “Aluminum is easier to cut and drill than steel, but welding it alters the internal structure of the aluminum near the weld points more than we expected, so that arm cracked near the welds when we dropped 2000 pounds of counterweights. It was frustrating watching a month of work and $300 dollars worth of aluminum in the new arm become scrap in 5 seconds. The next day we made a Frankenstein arm from pieces of our old steel throwing arms that we will use at the Young's Dairy exhibition tomorrow and the championships in Delaware in November.”

But Mr. Imlay reports expectations are still high, “Our goal this year? To set the world record!” The current world record for trebuchet is 2034.21 feet. But while winning and setting records is the goal, Mr. Nairn explains there’s more to throwing pumpkins than that. “I like the challenge of designing and building a simple machine to toss pumpkins over 2000 feet with my teammates, while drinking Yuengling beer.”

Scholarship

While also enjoying the social aspects, Mr. Imlay champions another goal, “This is the second year in a row that Rudolph Foods has sponsored our team. Rudolph Foods is a family company based in Lima, Ohio, and this year, they’re helping us provide a scholarship through the Midwest Pumpkin Chuck event for aspiring student chuckers. Our goal is to help students who are pursuing degrees in math, science and engineering. With the help of Rudolph Foods, we plan to give a $1,000 science scholarship to a student in 2012.”

Richard Rudolph, President of Rudolph Foods, describes the scholarship, “Rudolph Foods worked with Team American Chucker to set up a scholarship in conjunction with Punkin Chunkin. The sport of pumpkin chucking revolves around both math and science disciplines, and the scholarship is intended to encourage aspiring chuckers to pursue degrees in math, science and engineering. The hope is that this scholarship is the beginning of a long-lasting contribution to the Ohio community in the field of education. Student teams will compete at the First Annual Midwest Pumpkin Chuck, and the $1,000 scholarship will be awarded to a student on the winning team. Each team will be awarded various prizes as well.” For more information visit AmericanChucker.com.

Mr. Imlay invites everybody to watch the American Chucker team compete this year, “Watch the Science Channel’s Punkin Chunkin on Thursday, November 24th at 8:00 p.m. to see our team compete in the World Championships. We plan to compete again at Wright-Patterson base next year, and because the event is open to the public, it’s a great opportunity to bring the kids, watch some chucking and take part in the festivities. Pumpkin chucking is a great way to get our kids interested in science and engineering, and that’s our biggest goal.”

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