RC Motor & Prop Calculator
Precision Tool for Calculating Your RC Motor and Propeller Performance
Our advanced RC motor and propeller calculator helps pilots and RC enthusiasts accurately predict motor RPM, propeller thrust, efficiency, and performance metrics for both electric and nitro-powered RC models. Whether you're optimizing for speed, thrust, or efficiency, this tool provides reliable estimates.
Key Features and Applications:- Accurate motor RPM calculation - For performance tuning of all RC model types
- Propeller thrust analysis - Optimize prop selection for your application
- Efficiency calculations - Match motors and props for optimal performance
- Power system optimization - Select the right motor-prop combination
- Professional algorithms - Used by competitive pilots for accurate predictions
- Instant results - Advanced calculations with real-time updates
Our calculator references actual data from top RC motors and propellers, providing you with performance predictions closest to real-world scenarios. Whether for casual flying or professional competitions, it helps you find the optimal motor-prop configuration.
RC Motor & Prop Calculator Tool
Calculate motor RPM, propeller thrust, and efficiency for your RC model. Input your motor specifications and propeller details to get accurate performance predictions.
Electric Motor & Prop Calculator
Calculate performance for brushless electric motors with various propeller configurations.
💡 Need help finding these parameters? Click here for guidance
Electric Motor & Prop Results:
Nitro Engine & Prop Calculator
Calculate performance for nitro engines with various propeller configurations.
💡 Need help finding these parameters? Click here for guidance
Nitro Engine & Prop Results:
How to Calculate RC Motor & Prop Performance?
RC Electric Motor & Prop Calculation Examples:
| Model Type | Motor KV | Voltage | Prop Size | Blades | Thrust | Efficiency |
|---|---|---|---|---|---|---|
| Park Flyer | 1400 | 11.1V (3S) | 9×6 | 2 | 2.1 lbs | 78% |
| Sport Plane | 1000 | 11.1V (3S) | 10×7 | 2 | 3.2 lbs | 82% |
| Warbird | 800 | 22.2V (6S) | 12×8 | 3 | 5.8 lbs | 85% |
| 3D Aerobatic | 1200 | 14.8V (4S) | 9×6 | 2 | 2.8 lbs | 80% |
| Scale Jet | 600 | 29.6V (8S) | 14×10 | 3 | 8.2 lbs | 88% |
RC Motor & Prop Performance Chart Table
RC Electric Motor & Prop Formula:
Motor RPM = Motor KV × Battery Voltage
Prop Speed = Motor RPM × Propeller Pitch (inches) × 0.000947
Thrust = (Prop Diameter² × Prop Pitch × Air Density × RPM² × Blade Count) / 1000000
Efficiency = (Thrust × Prop Speed) / (Motor Power × 745.7) × 100%
Electric Calculation Examples:
Motor RPM = 1000 KV × 11.1 V = 11,100 RPM
Prop Speed = 11,100 × 7 × 0.000947 = 73.6 MPH
Thrust = (10² × 7 × 1.225 × 11,100² × 2) / 1,000,000 = 2.1 lbs
Efficiency = (2.1 × 73.6) / (200 × 745.7) × 100% = 78%
RC Nitro Engine Motor & Prop Calculation Examples:
| Engine Size | RPM | Prop Size | Blades | Thrust | Efficiency |
|---|---|---|---|---|---|
| .40 cu in | 12000 | 11×7 | 2 | 3.2 lbs | 75% |
| .46 cu in | 11500 | 12×8 | 2 | 4.1 lbs | 78% |
| .60 cu in | 11000 | 13×8 | 3 | 5.8 lbs | 82% |
| .25 cu in | 12500 | 9×6 | 2 | 2.3 lbs | 72% |
| .90 cu in | 9500 | 15×10 | 3 | 8.5 lbs | 85% |
RC Nitro Engine & Prop Performance Chart Table
RC Nitro Engine Motor & Prop Formula:
Prop Speed = Engine RPM × Propeller Pitch (inches) × 0.000947
Thrust = (Prop Diameter² × Prop Pitch × Air Density × RPM² × Blade Count) / 1000000
Efficiency = (Thrust × Prop Speed) / (Engine Power × 745.7) × 100%
Detailed Calculation Examples:
Example 1: .46 cu in Engine with 12×8 Prop
- Engine RPM: 11,500
- Propeller Diameter: 12 inches
- Propeller Pitch: 8 inches
- Number of Blades: 2
- Air Density: 1.225 kg/m³
Step-by-step calculation:
- Prop Speed = 11,500 × 8 × 0.000947 = 87.1 MPH
- Thrust = (12² × 8 × 1.225 × 11,500² × 2) / 1,000,000 = 4.1 lbs
- Efficiency = (4.1 × 87.1) / (300 × 745.7) × 100% = 78%
Result: 11,500 RPM / 4.1 lbs Thrust / 78% Efficiency
Example 2: .60 cu in Engine with 13×8 Prop
- Engine RPM: 11,000
- Propeller Diameter: 13 inches
- Propeller Pitch: 8 inches
- Number of Blades: 3
- Air Density: 1.225 kg/m³
Step-by-step calculation:
- Prop Speed = 11,000 × 8 × 0.000947 = 83.3 MPH
- Thrust = (13² × 8 × 1.225 × 11,000² × 3) / 1,000,000 = 5.8 lbs
- Efficiency = (5.8 × 83.3) / (400 × 745.7) × 100% = 82%
Result: 11,000 RPM / 5.8 lbs Thrust / 82% Efficiency
How to find these parameters? (Electric RC Motor & Prop)
- Motor KV Rating - Found on motor label or manufacturer specifications. Higher KV = higher RPM per volt
- Battery Voltage - Check battery pack voltage (3S = 11.1V, 4S = 14.8V, 6S = 22.2V, etc.)
- Propeller Diameter - Measure across the prop from tip to tip in inches
- Propeller Pitch - Found on prop label (e.g., "10×7" means 10" diameter, 7" pitch)
- Number of Blades - Count the propeller blades (typically 2, 3, or 4 blades)
- Air Density - Standard sea level is 1.225 kg/m³, adjust for altitude and temperature
Tip: If you changed prop size, update both diameter and pitch. Using exact motor KV (from manufacturer) gives the most accurate result.
How to find these parameters? (Nitro Engine & Prop)
- Engine RPM - Use a tachometer to measure at full throttle with your prop
- Propeller Diameter - Measure across the prop from tip to tip in inches
- Propeller Pitch - Found on prop label (e.g., "12×8" means 12" diameter, 8" pitch)
- Number of Blades - Count the propeller blades (typically 2, 3, or 4 blades)
- Air Density - Standard sea level is 1.225 kg/m³, adjust for altitude and temperature
Tip: Real nitro performance varies with tune, temperature, altitude and fuel. Measure after a full warm-up for the most representative numbers.
RC Motor & Prop Performance Influencing Factors
RC motor and propeller performance calculation involves several key factors that determine your model's thrust and efficiency:
| Parameter | Electric | Nitro Engine | Impact on Performance |
|---|---|---|---|
| Motor KV / Engine RPM | Motor KV × Voltage | Measured RPM | Higher = More Thrust |
| Propeller Diameter | Larger = More Thrust | Larger = More Thrust | Affects Thrust Output |
| Propeller Pitch | Higher = More Speed | Higher = More Speed | Primary Speed Factor |
| Number of Blades | More = More Thrust | More = More Thrust | Affects Efficiency |
| Air Density | Higher = More Thrust | Higher = More Thrust | Affects Performance |
RC Motor & Prop Performance Factors Table
Factor Explanations:
- Motor KV Rating / Engine RPM - Directly affects propeller speed, the fundamental parameter determining thrust output
- Propeller Diameter - Larger diameter = more thrust and better acceleration, but requires more power
- Propeller Pitch - Higher pitch = more speed but less acceleration, primary factor for top speed
- Number of Blades - More blades = more thrust but lower efficiency, affects overall performance
- Air Density - Higher density = more thrust, affected by altitude, temperature, and humidity
Pro Tips from Top Pilots:
- "Propeller selection is crucial - higher pitch props provide more speed, lower pitch gives better acceleration." - Professional RC Pilot
- "Start with manufacturer's recommended prop size, then adjust based on performance goals." - Competition Pilot
- Higher KV motors (2000+) need smaller props (8-10") to prevent overheating
- Actual thrust is typically 15-20% lower due to air resistance and prop efficiency
- For racing, target motor temps of 60-70°C for optimal performance
- Three-blade props provide 20-30% more thrust than two-blade props of same diameter
- Efficiency drops significantly above 80% throttle - consider larger prop for better efficiency
- Air density changes with altitude - reduce prop size by 10% for every 1000ft elevation gain
How to Use This Calculator:
- Select your power system - Choose between Electric or Nitro Engine tabs
- Enter motor specifications - Input KV rating and voltage for electric, or RPM for nitro
- Input propeller details - Enter diameter, pitch, and number of blades
- Set environmental conditions - Adjust air density for your flying conditions
- Calculate performance - Click calculate to get RPM, thrust, and efficiency
- Optimize your setup - Try different prop sizes to find the best performance