24 June – 30 June
Obtained our segmented track designs from the mechanical workshop and tested it
We found out that even though the idea was sound on paper, the gaps between each “track” actually caused some movement issues, resulting in the ice not being able to slide as far as we thought as the movement of the ice was bumpy.
Tried out various methods of freezing ice
- normal tap water
- boiled water which is cooled
- Pykrete – freezing soaked tissue paper.
Fig 7.1: Testing strength of Pykrete
- We found out that boiled and tap water showed no significant difference in strength and friction between steel and ice. That said, for pykrete, it is significant harder and more sturdy than ice but came as a trade off with high friction which resulted in limited movement.
Tested out our ice with the liquid nitrogen slit idea
Fig 7.2: Ice shaped for liquid nitrogen
- No significant increase in speed or decrease in friction
- Most of liquid nitrogen evaporates before reaching the ground
- Individual droplets exhibits their own Leidenfrost effect escapes through narrow gaps instead of remaining trapped under the ice
- Ice broke easily with slit
- Mold for ice was difficult to remove:
- Cling wrap method
- Aluminium tape method
- Scotch tape method
Further discussion of our gearbox stopping starting mechanism.
We came up with the 3D design of our gearbox with a loaded gun trigger and lock paw system
Change of Project Idea
- Dry Ice Hovercraft making use of sublimation of dry ice to form a thin layer of carbon dioxide and imitate Leidenfrost effect
- Discussion with Dr Ho regarding usage of dry ice as our vehicle: both has low friction and using dry ice seems to free us of many problems with ice
Fig 7.3: Sliding dry ice along the year 1 Physics Lab
- Consulted Kanesh and borrowed his existing motor to test concept
Fig 7.4: Testing feasibility of mounting motors on dry ice
We found that the dry ice was able to glide relatively smoothly although not consistently – rectify with two motors in opposite direction in future plans.