EDF Thrust Tube Calculator

The EDF Thrust Tube Calculator helps RC jet builders size the exhaust outlet area for an electric ducted fan installation. EDF performance depends not only on fan and motor selection, but also on how the inlet, ducting, and thrust tube control airflow.

What this calculator does

A thrust tube that is too restrictive can increase load and heat, while an outlet that is too large may reduce efflux speed. This calculator starts with fan case diameter and hub diameter, calculates fan swept area, and then provides single or dual outlet diameters for common percentage targets. It is useful for foam jets, composite jets, custom EDF conversions, and twin outlet installations. Enter the fan rotor or case diameter and hub diameter using the same units, then compare 100%, 95%, 90%, and smaller outlet targets. Example: for a 90mm fan with a 45mm hub, the calculator shows the fan swept area and outlet diameters for different nozzle percentages before cutting the thrust tube.

In practical terms: It calculates fan swept area and thrust tube outlet diameters for single or dual EDF exhaust layouts.

How to use it

Enter fan case or rotor diameter and hub diameter in the same unit. Review outlet diameters for several FSA percentages.

Example calculation

Use it when converting a 90mm EDF jet to a custom thrust tube and checking whether the outlet is near the desired FSA percentage.