Custom Jet Engines

Like the simple Jet Engine, custom jet engines provide thrust in atmosphere. Unlike simple jet engines, however, they consume fuel directly instead of power. There are 2 different types of CJE’s, large and small. The larger ones tend to be more fuel efficient while the small ones tend to be more space efficient.

Components

To make a functioning CJE all that is needed is a jet controller and a combuster. All of the add-ons, intakes, compressors, exhausts, connectors, and ducts are optional components.

The injector and extra combusters attach to the side of combusters and slightly increase the fuel consumption and effectively act like combusters, but at a greater cost. This can be useful for making a shorter CJE. The compressors, extra compressors, intakes, intake add-on, and exhaust increase the fuel efficiency of the CJE. Similar to the extra combuster the extra compressor is effectively a compressor that can give a slight increase to the efficiency. The connectors and ducts are used to redirect the exhaust and intakes to a more convenient location respectively.

Mechanics

Fuel consumption

The thrust, power, and energy production of the CJE is proportional to the amount of fuel consumed and the amount of fuel consumption is determined on the drive value, number of combusters, extra combusters, and injectors. If we represent the number of combusters with $B$, extra combusters with $B_e$, and injectors with $B_i$ the effective number of combusters for a large CJE equals:

$B_{L\,eff}= B + 0.1 * B_e + 0.2 * B_i$

And the effective number of combusters for the small CJE equals:

$B_{S\,eff}= B + 0.2 * B_e + 0.4 * B_i$

The max fuel consumption rate for the large CJE then equals:

$F_{L\, max}=1.2 * B_{L\,eff}$

And the max fuel usage for a small CJE equals:

$F_{S\, max}=0.25 * B_{S\,eff}$

Efficiency

The amount of thrust or generated power/energy produced by a CJE depends on the fuel consumption as well as the efficiency. The efficiency can be affected by the clearances, intakes, intake add-ons, exhausts, and the ration of effective compressors to effective combusters. If there is not enough clearance (8 blocks) for the intakes or intake add-ons their efficiency bonus will be reduced in proportion to the clearance. But if no intake is used for the CJE, this doesn’t matter.

If we assume there are no clearance issues, the number of intakes is represented with I, intake add-ons with Ia, exhausts with $E$, compressors with $P$, extra compressors with $P_e$, and the effective number of combusters with $B_{L\,eff}$the efficiency multiplier for large CJE’s equals:

$\eta_L=(0.6+0.4*I)(1+0.025*I_a)(1+0.1*E)(3-\exp\Bigl(\frac{1.459965}{2.106284+\frac{P+0.1*P_e}{B_{L\,eff}}}\Bigr)$

And for small CJE’s with the effective number of combusters represented with $B_{S\,eff}$ the efficiency multiplier equals:

$\eta_S=(0.6+0.4*I)(1+0.025*I_a)(1+0.1*E)(3-\exp\Bigl(\frac{1.459965}{2.106284+\frac{P+0.2*P_e}{B_{S\,eff}}}\Bigr)$

Outputs

The thrust output of a CJE depends on the clearances, fuel consumption rate and the efficiency of that CJE. If the final segment of the CJE doesn’t have enough clearance (10 blocks) the max thrust output will be reduced, but the fuel consumption will not change. For a large CJE the max thrust output equals:

$T_{L\, max}=10000 * F_{L\, max} * \eta_L$

And the max thrust output for a small CJE equals:

$T_{S\, max}=8000 * F_{S\, max} * \eta_S$

When a generator either power or energy can be produced with a CJE but doing so will limit the thrust output regardless of weather or not power or energy is even being produced at that time. If the final section of the CJE doesn’t have enough clearance, there will be absolutely no affect on the energy or power generation. For a large CJE the max power or energy output equals:

$G_{L\, max}=400 * F_{L\, max} * \eta_L$

And the max power or energy output for a small CJE equals:

$G_{S\, max}=400 * F_{S\, max} * \eta_S$