TrebuchetTeam Members:

Linda Hib, Charlene Obille, Hanh Phan, James Santos

Lab: Thursday 4 - 6

University of the PacificSchool of Engineering and

Computer ScienceDecember 4, 2003

Overview / OutlineResearch: Operation &

Development Guideline & Theory Optimization & Safety

Design: Design Simulations Sketches

Construction: Building the trebuchet

Competition Rank based on score

not distance

Report: Design Logs Final Sketches

Problem Definition

Introduction

Our objective was to build a trebuchet that would launch a one ounce hacky sack with certain constraintsThe overall grade is based on the performance, analysis, and the implementation of the design

ConstraintsDimensions: 2.5’by 3’ by 4’

Weight: 10lbs, anything over is penalized

Counterweight 12 pounds

Sling & Counterweight Anchor Non - Metal

Trigger 10’ from Trebuchet

Must be safeDowel Half-Inch minimum Hardwood

Objectives/Criteria

Build a trebuchet Use java simulation Analyze results Graph data Modify

Competition Time limit

Pickup Setup Launching in optimal conditions

Approach

L1 vs. Distance

Comparison Between Distance (ft.) and the Length of L1(ft.)

0

50

100

150

200

250

0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

L e n g th o f L 1 (ft.)

Le

ng

th o

f L

2 (

ft.)

Projectile

Angle vs. TimeAngles vs. Time

0

0.5

1

1.5

2

2.5

3

0 0.1 0.2 0.3 0.4 0.5 0.6

Time (sec)

Deg

ree

(rad

ian

s)

Projectile

Preliminary Ideas

Longer sling lengthShorter counterweight anchorSwing arm with varied settingsWide base designMetal braces for supportTrapezoid shaped sides

Sketches

Refinement

Trapezoid sides -> Triangle SidesShorter sling lengthLonger AnchorAdded an angled nail for sling releaseAdded ring to release sling for smooth releaseAdded metal sling track

Analysis

Energy Conservation: Dowel rotation (friction) Length of counterweight anchor Friction of release mechanism Length of sling

Decision / Implementation

Results / Discussion

Performance: 43’ Negative 25’ due to weight .7’ Offset

Weight 18 pounds

Score: -12.1

Suggested Improvements

Create a design that isn’t so wide.Use thinner cut wood.Multiple pre set release angles.Smoother dowel rotation.

Conclusion

The main problem with the trebuchet was that it weighed a lot.The weight of the trebuchet lead to poor score results.Design revisions lead to a drastic change in final design

Special Thanks

Tool and Workspace help: Wat Dhamawararam Buddhist Temple The Engineering Workshop

Instructors: Professor Litton & Golanbari

Influence: Poeun Hib

Stores: Home Depot