Hacky Sack Launch Mechanism By: Zachary Cowherd Wen Luu Keiichi McGuire

Overview Problem Definition – Introduction – Constraints – Criteria Approach – Preliminary Ideas – Refinement – Implementation

Overview Continued Results Suggested Improvements Conclusions – Key Criteria/Constraints – Final Design – Competition Performance – Improvements

Problem Identification Introduction The objective for this project is to create a Parabolic Hacky Sack Launch Mechanism (PHSLM) that will go down a slope and launch a hacky sack at the end aimed at a target 20ft away.

Problem Identification Criteria We have to build a device that can: – Traverse a ramp – Weigh a certain amount – Throw a hacky sack – Size of the device

Problem Identification Constraints The ramp will be 8ft in length It can weigh no more than 10lbs. The hacky sack has to be thrown 20ft. It must fit in a box 18 in 3

Approach Preliminary Ideas Design 1: A hinged arm would be propelled up and forwards by compressed springs. the arm would be pushed down and the ignition ram would lock into it

Preliminary Ideas (con’t) Design 2: the ignition system would be the same but this would launch out of a tube by compressing springs below the launcher and locking them in place with the ignition rod

Preliminary Ideas (con’t) Design 3: A rat trap style launcher by using would coils that would fling a arm with the hacky sack in it

Pros / Cons Design 1 – Too top heavy – Easily built Design 2 – Not accurate – Very consistent Design 3 – Similar to design 1 – Much better ignition design

Refinement Liked the release idea of design 3 instead of just releasing it, it would also hit a vertical stopper, countering the slope of triangle

Approach Implementation Final Design: – rat trap design – arm hits vertical stopper – release pin as trigger (simple) – heavy wheels to keep device upright

Results First Trial:18.92 feet from target Second Trial: 7.00 feet from target FOM Average: Performance Grade: 92/100 Design Quality: 78 9th place out of 31

Suggested Improvements More time to test and improve launcher Use better materials to build launcher More time to design release mechanism

Conclusions Key Criteria – Size of the device – Weight of the device Key Constraints – No larger than 18 in 3 – Can weigh no more than 10 lbs.

Conclusion (con’t) Final Design: – a “mouse-trap” style design – 4 “heavy” wheels to keep device right-side up – scoop shaped hacky-sack holder – vertical piece to counter-act the slope of ramp

Conclusion (con’t) Competition Performance – Group did well considering over night rebuild (9/31) – Figure of Merit (FOM): Average of – Closest trial was 7.0 feet from target

Conclusion (con’t) Key Improvements – Ramp available for trial runs – More time to improve design

Acknowledgements Home Depot – Knowledge of hardware Matt Conners and Chris Dockstader – Lending tools and materials