1. What is Effective Angle of Attack?

The Effective Angle of Attack (αeff) is the angle between the chord line and the direction of the local relative wind. It represents the actual angle at which the airfoil experiences the airflow, accounting for induced effects from wingtip vortices and other aerodynamic phenomena.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \alpha_{eff} \) — Effective Angle of Attack (radians)
• \( \alpha_g \) — Geometric Angle of Attack (radians)
• \( \alpha_i \) — Induced Angle of Attack (radians)

Explanation: The effective angle of attack is calculated by subtracting the induced angle of attack from the geometric angle of attack. This accounts for the downward deflection of the local airflow caused by wingtip vortices and other three-dimensional effects.

3. Importance of Effective Angle of Attack

Details: The effective angle of attack is crucial for understanding the actual aerodynamic performance of finite wings. It determines the lift coefficient, stall characteristics, and overall efficiency of the wing. Accurate calculation helps in aircraft design, performance prediction, and flight stability analysis.

4. Using the Calculator

Tips: Enter both geometric angle of attack and induced angle of attack in radians. Ensure values are non-negative and valid. The calculator will compute the effective angle of attack by subtracting the induced angle from the geometric angle.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between geometric and effective angle of attack?
A: Geometric angle of attack is the physical angle between the chord line and freestream direction, while effective angle of attack accounts for induced flow effects and represents the actual angle experienced by the airfoil.

Q2: Why is induced angle of attack subtracted?
A: The induced flow creates a downward component that reduces the effective angle of attack, hence it is subtracted from the geometric angle.

Q3: How does effective angle of attack affect lift?
A: Lift is proportional to the effective angle of attack up to the stall angle. A higher effective angle of attack generally produces more lift until stall occurs.

Q4: Does effective angle of attack vary along the wing span?
A: Yes, due to spanwise flow variations and wingtip effects, the effective angle of attack typically decreases toward the wingtips.

Q5: How is induced angle of attack determined?
A: Induced angle of attack depends on wing aspect ratio, lift distribution, and flight conditions. It can be calculated using aerodynamic theory or measured in wind tunnel tests.