RC Plane Electric Motor Calculator

Electric Motor Power Equation:

\[ P = (Weight \times Thrust\ Ratio) \times Constant \]

Required Power (P):

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1. What is the RC Plane Electric Motor Calculator?

This calculator helps determine the appropriate electric motor power (in watts) for your RC plane based on the aircraft's weight, desired thrust ratio, and an empirical constant factor.

2. How Does the Calculator Work?

The calculator uses the following equation:

\[ P = (Weight \times Thrust\ Ratio) \times Constant \]

Where:

\( P \) — Required motor power in watts
\( Weight \) — Total aircraft weight in grams
\( Thrust\ Ratio \) — Desired thrust-to-weight ratio (unitless)
\( Constant \) — Empirical factor (typically 0.1-0.15 for sport planes)

Explanation: The equation accounts for the relationship between aircraft weight, desired performance (thrust ratio), and the efficiency factor of electric motors.

3. Importance of Proper Motor Sizing

Details: Choosing the correct motor power is crucial for achieving desired flight performance while maintaining efficiency and battery life. An undersized motor won't provide enough thrust, while an oversized motor adds unnecessary weight.

4. Using the Calculator

Tips:

Enter total aircraft weight including battery
Typical thrust ratios: 0.5 for gliders, 0.75 for trainers, 1.0 for aerobatic
Start with constant 0.1 for sport planes, adjust based on experience

5. Frequently Asked Questions (FAQ)

Q1: What is a good thrust ratio for beginners?
A: For trainer aircraft, a thrust ratio of 0.7-0.8 provides good performance while maintaining stability.

Q2: How does battery voltage affect motor selection?
A: Higher voltage systems can use lower current to achieve the same power, but require matching motor KV rating.

Q3: Should I include battery weight in the calculation?
A: Yes, always use the total flying weight including battery, electronics, and airframe.

Q4: What if my calculated power seems too high?
A: Double-check your weight measurement and consider reducing thrust ratio for less aggressive flying.

Q5: How does propeller size affect motor selection?
A: Larger propellers require lower KV motors to maintain proper RPM. Always consult motor specs for recommended prop sizes.