What Is the Ground Effect Induced Drag Reduction (Wieselsberger) Calculator?
Ground effect is the increase in lift-to-drag ratio experienced by an airfoil operating close to a fixed solid or liquid boundary.
The physical ground blocks the downward development of the trailing vortex wake.
How Does the Ground Effect Induced Drag Reduction (Wieselsberger) Calculator Work?
Calculates height-to-span ratio h / b.
Evaluates the Wieselsberger interference factor sigma between 0 and 1.
Determines the effective ground induced drag coefficient and drag savings percentage.
Ground Effect Induced Drag Reduction (Wieselsberger) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Wieselsberger image vortex model for ground effect induced drag reduction.
How to Use the Ground Effect Induced Drag Reduction (Wieselsberger) Calculator
- Enter the aircraft height above ground and wingspan in meters.
- Provide the free-air induced drag coefficient CDi,0.
Step-by-Step Example Calculation
Light Aircraft Landing Flare
Input Values:
Understanding Your Result
When h/b = 0.1 (very close to ground), induced drag is slashed by over 50%.
When h/b > 1.0, ground effect is negligible (sigma approaches 1.0).
Factors That Affect the Result
- Height-to-span ratio (h/b): Ground effect intensity is entirely governed by proximity relative to span, not absolute altitude.
- Aspect ratio: Low-aspect-ratio wings experience greater proportional benefits from ground effect than high-aspect-ratio gliders.
When Should You Use This Calculator?
- Designing Wing-in-Ground-Effect (WIG / Ekranoplan) high-speed maritime transport craft.
- Analyzing landing flare distance, takeoff ground roll, and floating tendencies.
Assumptions & Limitations
- Assumes planar horizontal ground boundary without surface waves.
- Assumes steady level flight.
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard Wieselsberger (1921) theoretical formulation confirmed by flight test data.