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Aircraft Wing Induced Drag Coefficient (CDi) & Span Efficiency Calculator

Induced drag is the unavoidable aerodynamic drag byproduct of generating lift on a finite three-dimensional wing.

Operating cruise or climb lift coefficient

b² / S wing span squared divided by planform area

Calculated Result
0.01333

Induced Drag Coefficient (CDi)

Oswald Efficiency (e)

0.85

Calculation Breakdown

  1. Prandtl Lifting-Line Induced DragCDi = CL² / (π · AR · e) => 0.01333

CDi vs Wing Aspect Ratio

Interactive visualization based on your current inputs

CDi
0.00.30.50.81.0AR = 6 (Fighter)AR = 9 (Transport)AR = 20 (Glider)Aspect Ratio ARInduced Drag CDi

What Is the Aircraft Wing Induced Drag Coefficient (CDi) & Span Efficiency Calculator?

Induced drag is the unavoidable aerodynamic drag byproduct of generating lift on a finite three-dimensional wing.

Wingtip vortices downwash the airflow behind the wing, tilting the lift vector rearward into an induced drag component.

How Does the Aircraft Wing Induced Drag Coefficient (CDi) & Span Efficiency Calculator Work?

The calculation evaluates user-provided measurements using recognized domain equations, converts between measurement units, and adjusts for real-world efficiency factors.

Aircraft Wing Induced Drag Coefficient (CDi) & Span Efficiency Calculator Formula & Variables

The core mathematical equation utilized by this calculator is expressed as:

C_{Di} = \frac{C_L^2}{\pi \cdot \text{AR} \cdot e}

Prandtl lifting-line theory induced drag coefficient formula.

How to Use the Aircraft Wing Induced Drag Coefficient (CDi) & Span Efficiency Calculator

  1. Enter your primary measurements in the input fields above.
  2. Select your preferred units (e.g. metric or imperial) if applicable.
  3. Review or adjust operational assumptions such as field efficiency.
  4. Click Calculate to instantly generate the full results breakdown and visual chart.
  5. Use the Reset button at any time to clear the form and test a new scenario.

Step-by-Step Example Calculation

General Aviation Aircraft Cruise

Input Values:

liftCoefficientCl:0.50
wingAspectRatioAr:7.5

Understanding Your Result

Your calculated result represents the realistic operational capacity or baseline output under the specified conditions. Comparing theoretical and effective outputs reveals the direct impact of turns, overlap, and practical downtime.

Factors That Affect the Result

Field terrain, operator experience, equipment maintenance, overlap margin, and weather conditions can significantly influence real-world output.

When Should You Use This Calculator?

Use this calculator whenever you need quick, verified estimates for job planning, budgeting, equipment sizing, or project timelines.

Assumptions & Limitations

  • Higher aspect ratios (gliders, U-2) drastically reduce induced drag at low speeds.

Frequently Asked Questions

Calculation Accuracy & Reference Note

This calculator implements verified, deterministic mathematical equations based on published standards. Results should be treated as professional engineering estimates; always verify critical operations with local equipment manuals and site inspections.

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