Pumpkin Chuckin - Where Aerodynamics, Science, and Gourds Intersect Written 13 November 2014
by Duane Hyland, AIAA Communications (2008-2017)
Pumpkins can fly! Who Knew? The members of Team AIAA Greater Huntsville, that’s who. Composed of intrepid aerospace professionals from AIAA’s Greater Huntsville Section, the team took to the fields of Tate Farms in Meridianville, Alabama, to represent the section, and AIAA, in the farm’s “Pumpkin Blast 2014” competition, or as it’s colloquially known “some pumpkin chuckin.” At the end of the day, AIAA’s band of “pumpkin chuckers” placed 2nd in the events Adult Division, and earned the event’s “Outstanding Spirit and Blastmanship” award from the judges.
Team members, a mix of young professional, student, and professional members, were: Launch Crew: Brandon Stiltner, the team’s captain; Eric Becnel, Daniel Colty, and Michael Dunning. Team Members: Nathanial Long and Colin Moynihan. Other contributors were: Anthony Bartins, Ali Butt, and Tia Ferguson. Kenneth Philippart, the chair of the AIAA Greater Huntsville Section, served as the team’s program manager.
The team entered the competition not for potential glory or even for the advancement of pumpkin aerodynamic science and design, but because “we just wanted to see pumpkins fly through the air,” according to team member Brandon Stiltner. And who wouldn’t?
Each team’s propulsion device had to be capable of propelling a pumpkin weighing two to four pounds over a distance of at least 75 yards, with possible propellant systems including air cannons, catapults, slings, slingshots, or trebuchets. The team decided that a trebuchet, a medieval siege weapon used to fling heavy stones at the walls of cities, would be their “chuckin” device of choice. Once the team settled on the old device, they gave it a modern update, “once we had an idea of what the trebuchet was going to look like, we went to drawing sketches in computer-aided-design CAD,” explained team leader Brandon Stiltner. The computer analysis allowed for precision in the building process. Somewhere France’s Phillip II had to be envious. Once the team built and tested the design, it was off to the competition.
Each of the event’s teams where provided five pumpkins to “chunk,” and 30 minutes in which to chunk them at a target some 95 yards distant. Team AIAA Greater Huntsville longest chunk was 80 yards. Teams started the day with 350 points, from which the judges deducted one point per foot that the pumpkin finished away from the target. Teams earned bonus points if their pumpkins weighed more than four pounds, with the maximum weight limit being ten pounds. Other bonus awards included 50 bonus points for using trebuchet designs, and another 50 bonus points for the team finishing with the day’s longest “chunk, and another 50 points for winning one of the event’s special awards. The starting points, minus deductions, combined with any bonus points, determined the team placement in the event. The team’s longest “chunk” was 240 feet (80 yards).
Team AIAA Greater Huntsville also aided the next generation of aerospace during the event. “When one of the youth division teams had a major equipment failure, our team grabbed their tools and spare lumber and without hesitation, helped the high school team repair their machine,” said Team XXX member Ken Philippart, chair of the Greater Huntsville Section. “The event organizer, students and parents came up to us after the event and thanked AIAA for helping their kids. We couldn't have asked for a better way to give a favorable first impression of AIAA and a practical application of STEM in action!”
The neat part about the process, according to the team, wasn’t so much watching the pumpkins soar, or the application of practical engineering skills to but rather the teamwork and camaraderie that resulted from working on the device and competing. “This was a practical and educational engineering exercise but more importantly, the team came together as a team and became friends. They worked late into the night the week before the competition to meet the deadline,” explained Philippart, who continued “they are already hanging out together and planning other activities. And they reminded me that I told them if they won; I would take them all out to dinner. We have that scheduled for Friday!” Philippart concluded with a view toward next year, stating: “I have no doubt that through this competition, our section planted the (pumpkin) seeds for the next generation of AIAA leaders. They did AIAA and the Greater Huntsville Section proud!“
When asked about the role of aerospace technology in the team’s design, Philippart explained: “. When we started the design process, we talked about NOT having to comply with the aerospace engineering design philosophy of lighter, smaller and high tech. The guys all agreed that big and beefy would be better. But we discovered that there was a natural tendency for aero engineers to default to the aerospace design philosophy. For example, the guys used a composite beam for the launch arm which while very light and strong, flexed such that it affected the accuracy. Their axle design was not beefy enough and started bending during the competition although it did not fail. They went with a powered, remote controlled winch to cock the arm but by the end of the day, the battery was getting low and the winch was struggling. They had to attach ropes to help it.” Concluding: “The team members learned that light, small and high tech are great for things that fly but not for medieval siege machines! They also learned that our experiences color our perspectives and influence our design choices even when we are aware of them ahead of time. We default to what we know. Great lessons for young engineers to learn early in their careers!
Pumpkin Chucking has become a national sport in recent years, with a National Championship Tournament held every year in Delaware. Team American Chucker Inc., holds the current record for longest chuck, at 4,694.68 feet (1,564.66 yards), the team used a compressed air cannon to achieve the mark. Team Yankee Siege II holds the current trebuchet “chuck” record at 2,835.81 feet (945.27 yards). Surely the collective power of aerospace technology and know-how can beat these records in future years! Right?!