1. Idaho APPS
(Advanced Pumpkin Propulsion System)
2012
Team Members: Ramzi Sadeddinsarama, Joshua Bouma, Shelby Smith, Kara Peer, Andrew Schmohr
Sponsored by CALS, Kaufman Farms, and Lewiston Roundup Association

2. Problem Definition
The University of Idaho College of Agriculture and Life Sciences has asked our team to design and build a custom pumpkin cannon for their annual Clearwater Corn Maze in Lewiston, Idaho.

3. Specifications Accommodate 5”-8” diameter pumpkins
Ability to aim vertically and horizontally
Launch 100 to 150 yards
Ability to move around launch site
Short recovery time (1-3 minutes)
Cost less than $2500
Design life of 7 years
Safe to operate
Aesthetically pleasing

4. Concepts Considered
Compressed Air
Compression Springs
Tension Springs

5. Concept Selection Item Weight Compressed Air Compression Springs
Tension Springs
Ease of Use 50
8.8
6.2
7.6
Cost 30 6 7 8
Ease of Design/
Manufacturing 20
6.1
Total
100
780
640
742

6. Prototyping Prototype 1 Prototype 2 Short Chamber Long Chamber
Pressure (psi)
Distance (ft)
Average Distance (ft) 20
117
113.5
110 30
146
149.3
150
152
Prototype 1
Chamber
Sabot
Barrel
Ping-pong ball
Prototype 2
Long Chamber
Pressure (psi)
Distance (ft)
Average Distance (ft) 20
140
147.5
155 30
247
279.3
291
300
Chamber
Sabot
Barrel
Ping-pong ball

7. Basewad vs. Sabot Used in many propulsion systems (e.g. shotgun)
Basewad provides a flat surface
Sabot cups projectile
Sabot was chosen to accommodate pumpkins of different sizes
Small Pumpkin
Larger Pumpkin
Sabot

8. Final Design Accumulator tank equal size to barrel
Horizontal aiming with swivel plate at base
Vertical aiming with jack
Noise level maximum of 120 dB
Safe peak for single event
Mounted to frame with large wheels for easy transport

9. Math Model and Full Scale Testing
Melon Number
Pressure (psi)
Predicted Velocity (ft/s)
Actual Velocity (ft/s)
Actual Distance (ft) 1 35
198
177.5
331 2
189.4
173.1
292 3
180.1
312 4 45
234.8
202.4
431
Actual Velocity was slightly lower than predicted velocity
Predicted velocity did not include friction in the barrel

10. Health and Safety
To use the cannon at the Clearwater Corn Maze, it must pass UI Environmental Health and Safety requirements
Some client specifications could not be met because of these regulations
Future work would include design changes to meet these requirements

11. (Advanced Pumpkin Propulsion System)
Idaho APPS
(Advanced Pumpkin Propulsion System)
2012
Questions?