1. What is Brushless Motor RPM?

The RPM (Revolutions Per Minute) of a brushless motor is determined by its Kv rating, battery voltage, and throttle input. This calculation helps RC enthusiasts predict motor performance and select appropriate components.

2. How Does the Calculator Work?

The calculator uses the brushless motor RPM formula:

Where:

• \( Kv \) — Motor velocity constant (RPM per volt)
• \( Battery\ Voltage \) — Voltage supplied by the battery pack
• \( Throttle\ Percentage \) — Throttle position as percentage (0-100%)

Explanation: The Kv rating indicates how many RPM the motor will turn per volt with no load at 100% throttle. Actual RPM is proportional to the throttle percentage.

3. Importance of RPM Calculation

Details: Knowing the expected RPM helps in selecting proper propellers, predicting aircraft performance, and ensuring components operate within safe limits.

4. Using the Calculator

Tips: Enter the motor's Kv rating (found in specifications), actual battery voltage under load (not nominal voltage), and desired throttle percentage (0-100%).

5. Frequently Asked Questions (FAQ)

Q1: Why is my actual RPM lower than calculated?
A: Real-world RPM is affected by load, voltage sag under load, ESC efficiency, and other factors. This calculation assumes no-load conditions.

Q2: What's a typical Kv range for RC motors?
A: Small drones: 1000-3000 Kv, Large aircraft: 200-1000 Kv, Cars/boats: 1000-5000 Kv depending on application.

Q3: Should I use nominal or actual battery voltage?
A: For accuracy, measure voltage under load. Nominal voltage (e.g., 11.1V for 3S) overestimates RPM.

Q4: How does motor temperature affect RPM?
A: Increased temperature reduces efficiency and can slightly lower RPM due to increased resistance.

Q5: What's the relationship between RPM and thrust?
A: Thrust is proportional to RPM squared, but also depends heavily on propeller size and pitch.