T r e b u c h e t

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- - - - T r e b u c h e t - - - -

• By Jonathan Ching, Isaiah Lilly
• Karen Quach, Brain Westrick
• Lab Wednesday 6-8 p.m.

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Introduction

• Overview of our Trebuchet Design Project
• Approach and Final Product
• Constraints and Criteria
• Results and Discussion
• Improvements
• Conclusion
• Acknowledgments

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Constraints

• - maximum trebuchet weight- each
  trebuchet must have two operators- no other
  trebuchet operator contact or intervention
• permitted once the trebuchet is aligned
  and loaded- the final trebuchet design must
  fit into a box 4 ft long,
• 3 ft wide, and 2.5 ft high, when the swing
  arm is
• horizontal- the trebuchet will be
  activated with the operator 10 ft
• from the side- testing of the
  trebuchet shall be only conducted on
• Hand Hall Lawn, Brookside Field, Zuckerman
  Field,
• to the sunken field during daylight hours
  only hacky sacks may be hurled at any time

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Criteria

• size of each trebuchet with the swing arm in a
  horizontal position - 4 x 3 x 2.5.
• no weight restriction
• 60 seconds to fully prepare trebuchet 1pt
  penalty for each additional second
• Each design team select two operators who will be
  allowed to set up, load, and activate the
  trebuchet.
• sole energy source will be a provided 12-lb lead
  ball.
• Whamo Hacky Sack w/ mass of 28.8 g (1 oz) will
  be provided at competition.
• No other operator contact or intervention will be
  allowed once trebuchet is aligned and loaded.
• trebuchet will be activated with the operator 10
  ft from the side.

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Trebuchet Sketch

• Original
• The vertical beams were in the middle
• The original length of base was 3 ft.

• Final
• The vertical beams were moved to 2/3 from one end
• New length was 4 ft.
• Middle board so the sling arm went straight
• Piece of wood across the support beams for
  strength

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Project Photos
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More Photos
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Results

• Weight 15.13 lbs.
• Competition Hurl Distance 49 feet
• Offset From middle 1.6 feet
• Final Score -6.08

Discussion

• Comparing the different trebuchet designs we
  realized changes we could have made for a more
  efficient machine.
• Careful consideration of all the important
  scoring factors at the beginning would have
  benefited us in the end
• We were generally pleased with its performance on
  the launch day
• We now know what we would do differently next time

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• Recommendations on bettering our trebuchet
• Our trebuchet could have been lighter for
  the competition because the lightest was 5or 6lbs
  while ours weighed 15 lbs.
• Having wheels on the trebuchet would have
  increased the speed of the throwing arm and the
  maximum output of the throw altogether.
• Having a light throwing is would increase
  the rotation on the axis. Our group originally
  had a PCP pipe for the throwing arm because it
  was light and strong but we had trouble drilling
  straight holes in the pipe so we used a wood
  throwing.
• At the throwing competition the best throw
  was from a floating arm trebuchet. We suggest
  designing a floating arm trebuchet to maximize
  the throwing distance.

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Conclusion

• The weight of the trebuchet itself doesnt
  greatly affect the distance it is able to hurl a
  projectile
• The closer the counter weight is to falling
  vertically, the further the projectile can be
  launched
• Cooperation and careful schedule planning allowed
  for the best group dynamics

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Acknowledgments
We as a group would like to thank Isaiahs mom
for letting us use her office to construct our
trebuchet. We would also like to thank
Professors Golanbari and Litton for helping us
with our trebuchet and a great semester in
Engineering 5.