# THE SMALL CAT TRUCK-2

Favorite little Cat of Eva the Great Princess!

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:

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:

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

 Hydrogen Oxygen Density 0.07 g/cm³ 1.141 g/cm³ Molar Mass 1 16 Boiling Point 20.271 °K 90.188 °K Heat of Vaporisation 0.904 kJ/mol 6.82 kJ/mol Molar Heat Capacity 28.836 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):

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.