1. What is the RC Airplane Motor Size Calculation?

The RC airplane motor size calculation determines the required power (in watts) for an electric motor based on the desired thrust, flight speed, and motor/propeller efficiency. This helps select an appropriately sized motor for your RC aircraft.

2. How Does the Calculator Work?

The calculator uses the power calculation formula:

Where:

• \( Thrust \) — Required thrust force in Newtons (N)
• \( Velocity \) — Desired flight speed in meters per second (m/s)
• \( Efficiency \) — Combined motor and propeller efficiency (typically 0.7-0.9)

Explanation: The formula calculates the mechanical power needed to produce the required thrust at the desired speed, accounting for system inefficiencies.

3. Importance of Proper Motor Sizing

Details: Correct motor sizing is crucial for RC aircraft performance. An undersized motor won't provide enough thrust, while an oversized motor adds unnecessary weight and reduces flight time.

4. Using the Calculator

Tips:

• Thrust: Typically 0.5-1.5 times the aircraft's weight for normal flight
• Velocity: Cruising speed in m/s (1 m/s = 3.6 km/h)
• Efficiency: Start with 0.85 (85%) for brushless motors with good propellers

5. Frequently Asked Questions (FAQ)

Q1: How do I convert grams of thrust to Newtons?
A: 1 Newton ≈ 101.97 grams of thrust. Divide grams by 101.97 to get Newtons.

Q2: What's a typical efficiency value?
A: Good quality brushless motor systems typically have 70-90% efficiency (0.7-0.9).

Q3: How does this relate to battery selection?
A: Battery capacity (in mAh) and voltage must be matched to provide the calculated power for your desired flight duration.

Q4: What if I know my aircraft's weight instead of thrust?
A: For level flight, thrust needs to equal drag. As a rule of thumb, start with thrust equal to 0.7-1.0 times the aircraft's weight in Newtons.

Q5: How do I account for climb performance?
A: For aggressive climb performance, you may need 1.5-2 times the calculated power for level flight.