Wind Turbine Blade Input Form
Example Data Table
Use this sample set to test the calculator quickly.
| Input | Sample Value | Unit |
|---|---|---|
| Rotor Diameter | 90 | m |
| Blade Count | 3 | - |
| Rated Wind Speed | 12 | m/s |
| Tip-Speed Ratio | 7 | - |
| Air Density | 1.225 | kg/m³ |
| Power Coefficient | 0.45 | - |
| Drivetrain Efficiency | 92 | % |
| Root Chord | 4.2 | m |
| Tip Chord | 1.1 | m |
| Design Angle of Attack | 6 | ° |
| Lift Coefficient | 1.05 | - |
| Max Thickness Ratio | 18 | % |
| Capacity Factor | 38 | % |
| Availability | 96 | % |
Formula Used
This calculator combines rotor geometry, basic power extraction, and simplified blade-element momentum style section estimates for early-stage engineering design.
1. Blade length
Blade Length = Rotor Diameter ÷ 2
2. Swept area
Swept Area = π × Blade Length²
3. Angular speed
ω = (Tip-Speed Ratio × Wind Speed) ÷ Blade Length
4. Rotor speed
RPM = (ω × 60) ÷ (2π)
5. Available wind power
Pwind = 0.5 × ρ × A × V³
6. Rotor power
Prot = Pwind × Cp
7. Shaft power
Pshaft = Prot × Drivetrain Efficiency
8. Torque
T = Pshaft ÷ ω
9. Planform area per blade
Area = ((Root Chord + Tip Chord) ÷ 2) × Blade Length
10. Solidity
σ = (Blade Count × Mean Chord) ÷ (π × Blade Length)
11. Inflow angle
φ = atan(2 ÷ (3 × λr))
12. Simplified theoretical chord
c = (8πr sinφ) ÷ (3 × B × Cl × λr)
How to Use This Calculator
- Enter the full rotor diameter and blade count.
- Provide rated wind speed and tip-speed ratio for the operating point.
- Set air density, power coefficient, and drivetrain efficiency.
- Enter root chord, tip chord, lift coefficient, and design angle of attack.
- Add thickness ratio, capacity factor, and availability values.
- Press Calculate Blade Design to generate results.
- Review the summary metrics, blade section table, and Plotly graph.
- Export the results with the CSV or PDF buttons.
Frequently Asked Questions
1. What does this blade calculator estimate?
It estimates blade length, swept area, rotor rpm, tip speed, power, torque, annual energy, solidity, aspect ratio, and section-by-section chord and twist values.
2. Is this suitable for final manufacturing drawings?
No. It supports preliminary engineering only. Final blade design requires detailed aerodynamic optimization, structural verification, fatigue life checks, material selection, and certification analysis.
3. Why does the theoretical chord differ from my linear chord?
The linear chord is your chosen taper. The theoretical chord comes from a simplified aerodynamic relation that targets efficient loading at each blade station.
4. What is a good tip-speed ratio?
Modern horizontal-axis turbines often operate around 6 to 9. Lower values reduce noise but may raise torque demand. Higher values increase speed and can affect loads.
5. Why is the power coefficient limited?
The Betz limit caps ideal wind extraction at about 0.593. Real turbines operate lower because of aerodynamic losses, wake rotation, tip losses, and drivetrain losses.
6. What does solidity tell me?
Solidity compares blade area to rotor circumference. Higher solidity often means higher starting torque, while lower solidity usually supports faster, more efficient operation.
7. Can I use this for small turbines too?
Yes. The same relationships help with small systems, though airfoil choice, Reynolds effects, structural margins, and generator matching become especially important.
8. How is annual energy estimated here?
The calculator multiplies shaft power by yearly hours, then adjusts it using capacity factor and availability. It gives a fast estimate, not a full wind resource study.