By Dr. Martin Cwiakala, Special to the Sword and Shield
On Saturday, November 5, the Robo-Raiders won 3rd place and $250 dollars for the robotics team. The Robo-Raiders competed in the first annual Pumpkin Chunkin’ event sponsored by Theta Tau, an engineering fraternity at the University of South Carolina (USC). Students constructed a medieval catapult known as a trebuchet (pronounced treb-o-shay), which threw a 2-pound ball a distance of 30 yards. The team and machine were judged on knowledge, accuracy and maximum distance. Eleven teams from 9 high schools competed at this event held in a Lexington recreational park.
This event was selected as a preseason activity to help introduce the design process to this year’s robotics team, blessed with many Freshmen. Students learned about design, researched the problem, developed a design, created a prototype and built the full-scale trebuchet. Team leader Nathaniel Abraham, a Senior Engineering Design and Development student, found a computer trebuchet simulator which allowed students to experiment with various parameters and predict performance.
The goal for the trebuchet was to have a range of 40 yards. In the competition, it achieved 39 yards, speaking well of the design process. During the competition, the accuracy target range was changed from 40 yards to 30 yards. Keenan achieved 29- and 31-yard launches by adjusting the sling length. For the team’s final long-distance launch, an approach known as “propping the counterweight” was attempted. During this distance launch, the counterweight, which was suspended from a 2-foot arm was rotated 180 degrees and rested above the arm. This increased the gravitational potential energy of the 98-pound counterweight from 3 feet to 7 feet. On launch the trebuchet literally left the ground as the weight swung around, resulting in the shot being fired toward the ground. Next year the machine will be secured to the ground.
This was a very exciting competition. Keenan faculty members who attended included Mrs. Kirstin Bullington and Mr. KaReem Beckett, Science Teachers; Mr. James Coleman, Instructional Assistant; and Dr. Martin Cwiakala, Engineering Teacher. Students attending were Freshman Briana Abraham, Senior Nathaniel Abraham, Freshman Kaira Boyd, Sophomore Charann Brown, Freshmen Micah Crumpton, X’Avier Douglas and Carmen Hare, Junior Greg Lindsey, Freshman Mia Mack, Sophomore Zoe Ellis, Freshmen Kendra Entzminger, Nikia Franklin and Chibuzo Ibemere, Senior Terrell Ross and Freshmen India Glover and Ty’Kira Smalls. Other volunteers include Mrs. Peggy Cwiakala, who provided lunch. Support was provided by parents Mrs. Georgette Hare, Mr. Charles Hare, Mrs. Antionetta Entzminger, and Ms. Antonette Crumpton.
Links to photos of the build can be seen at http://tinyurl.com/keenantrebuchetpics. An accuracy launch video can be seen at http://tinyurl.com/keenantrebuchetvideo1 . A distance launch video is at http://tinyurl.com/keenantrebuchetvideo2 .
Dr. Cwiakala is Keenan’s Engineering Teacher.