#### snrdg082102

##### SOC-14 1K

I can not get a handle on the FC, Size Efficiency, FT, and fuel volume details for the self-contained thrusters on page 70 of TNE FF&S.

**FC**: Fuel consumption, in tonnes, per hour, tonne of thrust. To determine volume in cubic meters, multiply by the volume of the fuel type. For solid rockets, simply pick a fuel mass. Divide the mass by the FC value. The result is thrust in tonne-hours. Select either thrust or duration, and the other is determined from that. For example, 18 tonnes of TL-6 SF rocket fuel could have 2 tonnes of thrust for one hour, 4 tones for 30 minutes, 1 tonne for two hours, or any combination desired, as limited by the maximum allowed thrust (MaxT column).

**Size Efficiency**: Solid fuel rockets with less than 500 kg of propellant (fuel) mass suffer from inefficient fuel combustion. To determine the fuel consumption inefficiency of a solid fuel rocket divide 500 by fuel mass in kilograms. The result is the final fuel use multiplier. Multiply the calculated fuel consumption of the engine by this number. However, any multiplier less than 1 is treated as 1 and any multiplier greater than 10 is treated as 10.

**FT**: Fuel type burned. Note that at TL7+, any thruster which burns hydrocarbon distillates (HCD) may be designed to burn liquid hydrogen (LHyd) at no cost or energy penalty (the penalty is the vastly greater volume needed by LHyd).

*Fuel Volume*: The volume of fuel (in cubic meters) used per hour per tonne of thrust is equal to the mass (in metric tonnes) consumed per hour per tonne of thrust divided by the density of the fuel as show below.

Hydrocarbon Distillates (HCD) Density: 1; Price: Cr250

Liquid Rocket Fuel (LRF) Density: 1; Price: Cr1000

Solid Rocket Fuel (SRF) Density: 1; Price: Cr2000

Hydrogen Rocket Fuel (HRF) Density: 0.3; Price: Cr1000

Liquid Hydrogen (Lhyd) Density: 0.07; Price: Cr35.

In fuel consumption to convert fuel consumption from tonnes/hr./tonnes of thrust you use the volume of the fuel type. To determine the fuel volume divide the mass (in metric tonnes) consumed per hour per tonne of thrust by the fuel density.

None of the above is making any sense to me. Can anyone provide me with an example of how the rules work?