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Favorite little Cat of Eda the Great Princess!

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Little bit of math

The truck has been design to use gaz turbine, Hydrogen and it's oxydizer, Oxygen. Let's take a closer look to that concept:

Water Equation

By mass, the ratio of Hydrogen by Oxygen is stoichiometrically 8:1, but in rocketery the NASA use a ratio of 6:1, for ISP(Thrust efficiency) reason:

Water Equation by mass

For this project, I will use the stechio ratio, 8:1. The data of the gaz are:

Density0.07 g/cm³1.141 g/cm³
Molar Mass116
Boiling Point20.271 °K90.188 °K
Heat of Vaporisation0.904 kJ/mol6.82 kJ/mol
Molar Heat Capacity28.836 J/(mol*K)29.378 J/(mol*K)

The most important in this document is resume on this page:


The experimental data give us, from Praxair (a large manufacturer):

Energy Cost

As in the text, the magic number is about 15 kwh/kg of liquid Hydrogen. In it's current draft configuration, the tanks of the truck may contain less than 140 L of liquid. In volume, 1 g / 0.07 g/cm³ = 14.28 cm³, and 8 g / 1.141 g/cm³ = 7.01 cm³, and the ratio is 14.28 / 7.01 = 2.04:1. In the tanks, 93L of Hydrogen and 47L of Oxygen.

Water Equation by mass

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