CASTLE DEFENSE

1
CASTLE DEFENSE

• By Clayton Nylander and Amy Gordon

2
Questions to be answered

• How much will pouring hot oil/water really hurt?
• Which type of armor protects you best?
• What conditions would cause the liquid to be
  cooled?

3
Background

• Machicolations were holes through which boiling
  liquids (water, oil, pitch) were poured
• Castle walls typically 30-80 ft high

4
1. How much will pouring hot oil/water really
hurt?

• Assumptions
• Forced convection over flat plate
• Liquid travels through holes, so flow has tight
  diameter (0.04m)
• 20 m drop
• Neglect evaporation (evaporation would decrease
  final temperature)
• Fundamental Relationships

5
1. How much will pouring hot oil/water really
hurt?

• Temperature at bottom of fall (beginning at
  boiling temp)
• Water, Tbottom 372.999928 K
• Oil, Tbottom 429.9997304 K
• Conclusion Third degree burns occur
  instantaneously without protection

6
2. Will any type of armor save you more than the
other?

• Fundamental Relationships

Heat transfer due to free convection regarded
negligible
7
2. Will any type of armor save you more than the
other?

• Oil
• Leather (0.005 m thickness)
• Ti 346.208 K
• Steel (0.002 m thickness)
• Ti 428.829 K

• Water
• Leather (0.005 m thickness)
• Ti 329.075 K
• Steel (0.002 m thickness)
• Ti 372.386 K

• Conclusion Leather is better protection against
  boiling liquid

8
3. What conditions would cause the liquid to be
cooled?

• Increase Height
• Water
• At 20 m, Tbottom 372.999928 K
• At 200 m, Tbottom 372.98128 K
• Oil
• At 20 m, Tbottom 429.9997304 K
• At 200 m, Tbottom 429.929911 K
• Conclusion Cooling is not enhanced, even after
  absurdly large distances.

9
3. What conditions would cause the liquid to be
cooled?

• A windy or extra cold day
• Cooling of liquid before pouring
• Scattering of droplets
• Evaporation

10
References

• http//www.sapiensman.com/conversion_tables/specif
  ic_weights.htm
• http//www.cqc.state.ny.us/newsletter/estime.htm
• http//www.hp-lexicon.org/images/rj/rj_castle.gif
• http//www.richmondancestry.org/images/castle_suns
  et.jpg
• http//dictionary.reference.com/illus/illustration
  .html/ahd4/Machicolations/machic