There was only one entry in Salisbury High School’s annual turkey toss competition, but physics teacher Paul Koba said he found the trailer-mounted trebuchet machine “impressive.”

Since the mid-1990s, Koba has offered his physics students extra course credit if they applied the principles he teaches in a course module that studies the simple siege machines used in Medieval times by armies seeking to toss fire-bearing missiles designed to capture opponent’s castle defenses.

Koba started the practice when he found himself the recipient of multiple frozen turkeys awarded around Thanksgiving bowling tournaments. He saw it as a way to more deeply involve his students in the course module built around the study of siege weapons employed by Medieval armies. He also saw the competition as way to recognize students for other than sports prowess.

Since the first competition, almost 30 years ago, Koba has kept the same frozen turkey to keep the competition level from year to year as his students seek to break the turkey toss record. The longest toss record of 92 yards was set in 2014. The competition normally attracts multiple entries, but this year Michael Staack’s was the only one.

It was impressive in its scale and weight and had to be mounted on a trailer because it would have been so unwieldy otherwise.

Staack said he found most of the materials in his machine in his father’s 5,000-square-foot garage at the Staack homestead. He said he had “less than $100” invested in his project. Most of that went into concrete and other material in the trebuchet’s 1,200-pound counterweight fashioned around a used 50-gallon drum.

Staack’s father, Josh, an automotive instructor at Lehigh Career and Technical Institute in Schnecksville, helped Matthew with the technical welds in his son’s trebuchet, “but the design is all his.” Dad also provided the trailer and tow vehicle the heavy machine required.

Even as he watched the trebuchet toss the frozen turkey 30 yards down the athletic field, Matthew said he wanted to modify the counter weight to give the machine more energy. He asked Koba if he could return after the modification to try again with the same turkey.

Matthew’s brother, Nathan, who will be in Koba’s physics class in a few years, said he has his eye on keeping the machine around for him to modify when his turn comes.

Koba, for his part, said the shirt-sleeve weather Nov. 26 just “did not feel like the November weather” he was used to. “I’ll have to grab that turkey and get it back in the freezer before it thaws,” he joked.