HSIM supports two models for filling the flight tank. The first mode is typical of tanks that are filled with a pin-hole vent. Flight-tank pressure will be somewhat less than supply-tank pressure, but both are highly dependent on ambient pressure.

In this model, HSIM requires the pressure of the supply tank and a pressure drop between the supply tank and the flight tank.

Hsim's second model assumes that the pressure of the nitrous in the flight tank is regulated by a pressure relief valve. For this model, HSIM requires the pressure of the nitrous supply tank and the pressure of the flight tank.

In both models the pressure of the supply tank is provided by giving a temperature of that tank. HSIM then calculates the supply pressure by assuming the tank is at saturation conditions.

Specifies the pressure of the regulated flight tank. Use this parameter when you have a pressure regulator on your flight tank that sets the pressure to a known value.

The supply tank is presumed to be in gas/liquid equilibrium (saturation). Supply tank pressure is calculated from this temperature.