Getting started

ThrustLab predicts how an electric drone powertrain will perform before you build it. You describe the parts — a propeller, a motor, an electronic speed controller (ESC), and a battery — and ThrustLab simulates how much thrust they make, how much power they draw, and how hot they get. This page explains how a simulation works and how to read what comes back.

If you have never run one before, start here: pick a propeller, motor, ESC, and battery, press run, and read the thrust and power numbers. Everything else on this page fills in the detail behind those numbers.

How a simulation works

A simulation answers one question: at a given throttle, in a given airspeed, what does this powertrain do? You give ThrustLab four components and an operating point, and it solves the physics that couples them together.

• Propeller — converts shaft power into thrust. Its diameter and pitch set how much air it moves.
• Motor — turns electrical power into shaft power. Its velocity constant (Kv) sets how fast it spins per volt.
• ESC — feeds the motor the right current. It sets switching behavior and adds a small loss.
• Battery — supplies the voltage and current, and sags under load.

ThrustLab balances all four at once: the propeller demands torque, the motor and ESC supply it from the battery, and the battery voltage drops as current rises. The result is a single self-consistent operating point — the thrust, current, power, and efficiency you would actually measure on a bench.

Reading your results

Every result reports the same core numbers so you can compare designs directly. Thrust is the force the propeller produces, usually in grams or newtons — higher is more lift. Power is the electrical power drawn from the battery in watts — lower is better for the same thrust. Efficiency ties them together as thrust per watt; a higher value means a longer flight on the same battery.

A reasonable hover point for a 5-inch quad rotor sits near 1:1 thrust-to-weight at part throttle, drawing tens of watts per motor. If a number looks far outside what you expect, check the component specs you entered before trusting the prediction.

Accuracy & fidelity

A simulation is a prediction, not a measurement — it is best used to compare designs and find the right ballpark, then to confirm the final build on a bench. ThrustLab couples four physics models that are validated against real data, but the result can only be as accurate as the parts data you feed in.

Where the numbers come from:

• Propeller — ThrustLab uses a vortex-BEM solver: a Drela vortex-based blade-element model that closes the local inflow at each blade station and corrects for tip Mach and compressibility. It is validated against the UIUC propeller database. Because the model works the blade station-by-station, it flags any stations that did not converge or that are running past drag divergence.
• Motor & ESC — an electromagnetic + thermal model predicts current, RPM, losses, and winding/magnet temperatures. Its accuracy depends on the motor's Kv, resistance, and pole count being correct — published specs vary, so a motor with good data predicts better.
• Battery — voltage sag and drain are modeled from the pack's capacity, resistance (or C-rating), and chemistry. A pack with an accurate internal resistance sags realistically under load.

Two practical rules of thumb. First, garbage in, garbage out: if a motor's published resistance or a prop's pitch is wrong, the prediction inherits that error — sanity-check the specs you entered before trusting an answer that surprises you. Second, ThrustLab flags when it is operating outside its comfort zone (a convergence warning, blade tips past drag divergence, or a battery running hot), so treat those warnings as a signal to look closer rather than ignore.

Next steps

Once you can read a single run, the rest of the User Guide goes deeper: the Glossary defines every term, New simulation explains each input field, Results explains each output, and Warnings explained covers what to do when a run flags a problem.

Units (Metric or Imperial)

The Units toggle on your Account page chooses whether inputs and results are shown in Metric or Imperial. It is an account-wide preference: changing it converts every unit-bearing field and result across the whole app at once — thrust, temperature, airspeed, torque, weight, and so on — so you never have to pick a unit per field. New accounts start on Imperial.

Switching units never changes the underlying numbers. ThrustLab always stores your data in metric and converts only for display, so toggling back and forth is lossless — the same simulation reads "1000 gf" in metric and "2.20 lb" in imperial, but the stored thrust is unchanged.

When to change it. Set it once to whichever system you think in. Find it on the Account page under your plan; the change takes effect across every page after a quick refresh.