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

By Jonathan Ching, Isaiah Lilly

Karen Quach, Brain Westrick

Lab: Wednesday 6-8 p.m.

Introduction

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

- 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

Constraints

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.

Trebuchet SketchOriginal•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

Project Photos

More Photos

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

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.

Conclusion

• The weight of the trebuchet itself doesn’t 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

Acknowledgments

We as a group would like to thank Isaiah’s 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.