STW CORP
Project Catapult
Introduction:
The qualifications of a good catapult is one that can hit many different ranges and at different elevations. We proposed to create a catapult that swings it's arm through the use of a torsion bundle. Rough diagrams to the side ->>>
Ideas Behind Design:
For the swing arm, hockey sticks were used because they are made for extreme flex and impact so during launches it would not break. To continue, to hold the ball, we used a tea strainer since they are round and easy to drill onto the arm. We tried using scoopers from the dollar store but found that this caused the ball to fly very high but not very far horizontally. There was also padding that stopped the arm at around 75 degrees. It was important that the arm did not stop at a right angle from the ground because the ball would not gain any vertical height, giving it less time to go farther. We found that having only the torsion bundle to provide energy to the arm was not enough to make the ball go 10 metres and more so we added bungee cords. The bungee cords could be wrapped different amounts of times which would change the speed at which the arm swung, and thus the distance the ball travelled also. As a launching mechanism, we attatched string to a screwdriver which was inserted into a slot beside the end of the arm. Upon pulling the string, the screwdriver would release the arm from a safe distance.
Materials:
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2x4 wood pieces
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scrap wood at home
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home depot - about $12
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2 hockey sticks
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borrowed from a friend
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screws
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had at home
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2 bundles of 100' string
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dollar store
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Dowel
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home depot - $3
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Bungee cords
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dollar store and home
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pool noodle
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dollar store
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Story Board
Timeline
May 12, 2016
Blueprints and Storyboard
Rough copy of storyboard for commercial created by Dilsha and blueprints for catapult created by Vineet
May 27, 2016
Building process extended to May 29
Catapult Created
Supplies cut to measurement at home depot and put together at Dilsha's house. Also includes testing if catapult works with different distances.
May 29, 2016
Started May 30 instead
Video
Video taping for commercial and putting together clips/editing
May 28, 2023
Launch day
Put it to the test for max range and accuracy
Test Day
Results:
Distance: 10m Elevation: Net (1.2m)
Distance: 14m Elevation: Ground (0m)
Distance: 18m Elevation: Ground (0m)
Average Maximum Distance: 20.37m
Conclusion:
To conclude, our catapult performed much better than expected. We believe the reason for not achieving the third target was the weather. It was very windy on launch day and this made it hard to calibrate the catapult correctly as the conditions would change when we were launching for a mark. The wind would make the ball go farther but more to the left of the target and when the wind died down, the catapult arm would not throw the ball far enough. On launch day, we knew the requirements the catapult needed to achieve in order to be a good catapult, variables such as target height and distance, but we did not know how the weather would play a factor until the day of the test.
<<<<<<Video from test day.