Friday, April 14, 2017

From Tech & Engineering teacher, Mark Rocheleau....

On the left is Trevor Shrady and on the right is Nick Maciel.

This project is a culmination of our studies of fluid dynamics primarily but not strictly applied to propulsion systems.  Students are provided a balsa wood "blank" and are allowed to create any design they wish provided it adheres to strict competition and safety rules. They begin by sketching possible designs; they then decide on a final design and complete a detailed drawing of their dragster idea using either Sketchup or a multi-view hand drawing.  Some excellent examples may be seen hanging on the bulletin board in the hallway outside of room 211. Students are given the opportunity to use what they've learned in class to design their car as well as to investigate other related disciplines, such as aerodynamics, to further improve their design.

Once built and inspected, students test fire their dragster and speed is determined with a radar gun.  Some cars actually reach 42MPH!  That data is used to create a double elimination bracket.

Launching the dragsters involves a coordination of students and technology.  Dragsters are guided safely down the track using fishing line threaded through two eye hooks in each car.  CO2 cartridges are placed inside the cars and are punctured using 3d-printed caps which hold nails held securely against the ends of the cartridges.  A pneumatic pump is used to charge air tanks that are released on command using a manual lever.  The air simultaneously extends two pistons which strike the nails at the same time, launching each car.  Students volunteer for jobs including setting up, launching, recording video, recording slow-motion video at the finish line (for those too-close-to-call finishes), deceleration zone personnel (a large plastic bag is used to slow the cars to a stop before they hit the end) and finally, someone is responsible for operating the radar gun.

Students take great pride in their creations and are able to explore areas of study within and just outside the curriculum in an attempt to make the fastest car.  The hands-on aspect is critical to many.  For example, although we discussed gas laws governing the relationship between volume, temperature and pressure, some students are still amazed when they pick up a used CO2 cartridge and realize it's very cold.  Suddenly, the concept is real.

Photo Courtesy of Jon O'Connor

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