Drone Propeller Size Calculator

Propeller Size Equation:

\[ \text{prop\_size} = 2 \times \sqrt{\frac{\text{thrust}}{\pi \times \text{density} \times \text{efficiency} \times \text{velocity}^2}} \]

Thrust:

Air Density:

kg/m³

Propeller Efficiency:

(0-1)

Air Velocity:

m/s

Propeller Diameter:

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1. What is the Propeller Size Equation?

The propeller size equation calculates the optimal diameter for a drone propeller based on required thrust, air density, propeller efficiency, and desired air velocity. Proper propeller sizing is crucial for efficient drone operation.

2. How Does the Calculator Work?

The calculator uses the propeller size equation:

\[ \text{prop\_size} = 2 \times \sqrt{\frac{\text{thrust}}{\pi \times \text{density} \times \text{efficiency} \times \text{velocity}^2}} \]

Where:

\( thrust \) — Required thrust in Newtons (N)
\( density \) — Air density in kg/m³ (1.225 at sea level)
\( efficiency \) — Propeller efficiency (0-1, typically 0.7-0.85)
\( velocity \) — Desired air velocity in m/s

Explanation: The equation balances thrust requirements with propeller efficiency and air velocity to determine the optimal diameter.

3. Importance of Proper Propeller Sizing

Details: Correct propeller size affects drone performance, battery life, stability, and noise levels. Oversized propellers may overload motors, while undersized ones may not provide enough thrust.

4. Using the Calculator

Tips:

For standard conditions, use air density of 1.225 kg/m³
Propeller efficiency typically ranges 0.7-0.85
Velocity depends on your drone's desired speed
All values must be positive numbers

5. Frequently Asked Questions (FAQ)

Q1: What's typical propeller efficiency?
A: Most drone propellers have 70-85% efficiency. High-quality propellers may reach 85-90%.

Q2: How does air density affect propeller size?
A: Higher density (lower altitude/colder air) requires smaller propellers for same thrust. At high altitudes, larger propellers are needed.

Q3: What's a good air velocity for drones?
A: Typically 5-15 m/s for most applications, but depends on drone purpose (hovering vs high-speed flight).

Q4: How does propeller size relate to motor KV rating?
A: Higher KV motors work better with smaller propellers, while lower KV motors can handle larger propellers.

Q5: Should I round up or down the calculated size?
A: Choose the nearest standard propeller size. It's better to slightly oversize than undersize for most applications.