Smatterings of applause were mixed with sighs of frustration in the Duffield Hall atrium April 30, as engineering students showed off their air motors on the penultimate day of classes.

The goal for the sophomore mechanical engineering students: build a motor powered only by compressed air that would pack enough punch to push a flat cart up a slight incline.

The project culminated the students' coursework in MAE 2250, Mechanical Synthesis, one of the first required courses for mechanical engineering majors. Co-taught by Professors Michel Louge and Zellman Warhaft, the course showed students how to use machine tools and involved two projects, the second of which was the air motor. Earlier in the year, the students built devices that could stamp a dog tag with the letters "CU."

For the first time, the professors decided to hold the final air motor project demonstration publicly to show people just what goes on in a mechanical engineering design class, Louge said.

Working in teams, the students built 10 kg motors that were mounted on a flat cart. The contraption was required to travel at least 4 meters up a 1 percent graded incline, using only 10 gallons of compressed air, at 40 pounds per square inch. The motors were designed from cylinders and pistons, Louge explained.

The students were assessed on their adherence to and documentation of the design process -- not necessarily the performance of the motor.

"But of course, being the competitive Cornell students they are, they will always attempt to have the best possible motor," Louge said. "That's good."

While some students experienced technical difficulties -- and maybe performance anxiety -- some students' motors were a roaring success. One motor was built so efficiently by Taylor Dujack, Ravi Surdhar and Jimmy MacDonald that the cart even moved with Dujack standing on it.

Dujack had been wavering on choosing his major, but the success of his air motor has helped him reach a decision.

"To finally actually be able to build something is really validating," Dujack said. "I think this is going to be the thing that solidifies it."