The Creation of Hera by yurtgc548

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									The Creation of Hera

          “The Treb Tigers”
             Stacy Costello & Jennifer Shore
   oh, and the dudes too: Travis Ford & Kevin Petros
                 University of the Pacific
                     Engineering 5
                     Lab: Tues, 6-8
Hera
Overview

n   This presentation will cover the design,
    testing, and analysis process that our
    group performed. Our goal was to
    successfully build a working trebuchet
    and to launch it in a competition against
    our fellow E-5 classmates.
Outline

n   Problem Definition
n   Design Approach
n   Results and Discussion
n   Suggested Improvements
n   Conclusions
n   Credits
Problem Definition

n   Our task was to design and build a fully
    operational trebuchet following
    guidelines provided by the instructors of
    E-5, Fall 2003. A trebuchet is a siege
    machine that uses a counterweight, arm
    and sling to launch various objects in
    battle at the opposing forces.
Working hard to define the problem
Problem Definition (cont.)

n   Constraints:               n   Criteria:
    – Must fit in a 3x4x2.5’       – Must launch a 1 oz
      box                            WAMO hacky sack
    – No weight restriction,       – counterweight must
      but penalty                    be 12 pounds
    – No prefabricated             – must be released
      components                     from 10 feet away
Design Approach

n   Preliminary Ideas:
    – we wanted a simple,
      yet efficient design that
      used a minimal
      amount of materials,
      thus reducing the
      weight.
    – we contemplated using
      wood or PVC pipe for
      the frame.
Refinement

n   Pros             n   Cons
    – Simple             – Over engineered
    – Sturdy             – arm was too
    – Fairly light         heavy
                         – Large release
                           mechanism
A little friendly fighting…




After all, boys will be boys.
Construction

n   Materials           n   Tools
    –   Wood                –   Table Saw
    –   Screws              –   Power drill
    –   U-bolts             –   Screw drivers
    –   Nylon rope          –   Wire cutters
    –   Stacy’s jeans       –   Needle and thread
    –   Metal rings
    –   Steel rod
    –   Dowel rod
Construction (cont.)
Analysis
n   Use of
    Algobeautytreb.com
    – Optimal lengths: arm
      length ratio 4-1, 30° pin
      angle, ¾ of arm sling
      length.


n   Field testing confirmed
    computer analysis.
    – Sunken field
Testing in the
Sunken Field
Decision/Implementation
                      Final Sketch
Final Trebuchet

                  Setting up at the competition
Results/Discussion

n   Projectile Distance
    50ft
n   Off by 6ft
n   Overall score -0.6
n   Major Problems
    – Weight
    – Accuracy
Suggested improvements

n   Smaller wood
n   Use drill press
n   Smaller release mechanism
n   Lighter arm
n   Paint it pink
Conclusions

n   Learned how various factors affect the
    performance and overall score.
    – Weight
    – Accuracy
    – Design
    – wind
n   Teamwork was key!
n   We love our group!
Acknowledgements
n   Ripcord.com
n   Trebuchet.com
n   Algobeautytreb.com
n   Backyardartillary.com
n   Dr. Litton
n   Dr. Golanbari
Pictures!
The End

								
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