Dragon Fire (D&D calc)

Published by Deer Lord in the blog Deer Lord's blog. Views: 281

Dragon fire is very intense, how intense?

well, there's these
- Monster Manual 3.5e
- Draconomicon (4e)

The most common component of treasure in D&D is, well gold.
But gold is a metal, it doesn't turn to ash. If so, then what would be considered 'Obliterated' or 'Destroyed' in this case? I think vaporizing makes sense, considering even magical items gets reduced to nothing but a bit of ash.

Gold boils at about 2700 degrees Celsius.

Dragon Fire is shot in the form of a cone with varying size depending of the size of the Dragon.
According to the 5e manual, we have 15 ft. for wyrmlings, 30ft. for youngs, 60ft. for adults and 90ft. for ancients. (A cone of 15 ft. = a cone with such length at its sides)
This diagram in the sourcebooks suggests a 90 degree angle, meaning the base of the cone is sqrt(2)*(cone length).

I'm looking for cone volume, and then I'll be looking for how much energy is needed to heat up that much air to 2700 degrees.

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Cone Volumes:
Using Cone calculator and given s and r, we get
Wyrmling: s= 4.57m, r=3.23 m, V=35.32 m^3
Young: s= 9.14m, r= 6.46m, V= 282.57 m^3
Adult: s= 18.28m, r= 12.92m, V= 2260.55 m^3
Ancient: s= 27.43m, r= 19.39m, V= 7638.85 m^3

Air density would be about 1.196 kg/m^3 in a European setting at room temp (20 degrees)
Specific heat of air is 1006 j/kg
I'll use the Q=m*c*t equation

Therefore:
Wyrmling: V=35.32 m^3, m=35.32*1.196=42.24 kg, Q=42.24*1006*2680= 113882419.2 J
Young: V= 282.57 m^3, m=282.57*1.196=337.95 kg, Q=337.95*1006*2680= 911150265.42 J
Adult: V= 2260.55 m^3, m=2260.55*1.196=2703.62 kg, Q=2703.62*1006*2680= 7289169878.224 J
Ancient: V= 7638.85 m^3, m=7638.85*1.196=9136.065 kg, Q=9136.065*1006*2680= 24631561046.768 J

Final Tally:
Wyrmling red dragon's fire breath= 0.027 tons of TNT
Young red dragon's fire breath= 0.217 tons of TNT
Adult red dragon's fire breath= 1.74 tons of TNT
Ancient red dragon's fire breath= 5.88 tons of TNT

This is probably an underestimation of the more powerful dragons, but nice bit feats for young dragons.
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