Calculator Form
Use the same length unit for rise and span values.
Formula Used
Angle from rise and half-span: tan(θ) = rise ÷ half-span
Angle in degrees: θ = arctan(rise ÷ half-span) × 180 ÷ π
Angle from full span: θ = arctan((2 × rise) ÷ full span)
Rise from angle: rise = tan(θ) × half-span
Full span from angle and rise: full span = (2 × rise) ÷ tan(θ)
Root-to-tip length: √(half-span² + rise²)
Rise percentage: (rise ÷ half-span) × 100
How to Use This Calculator
- Select the calculation mode that matches your known values.
- Choose whether you are entering full span or half span.
- Select metric or imperial units.
- Enter one tip rise value, or fill left and right rise.
- Enter the span value or angle, depending on the selected mode.
- Press calculate to show the result card above the form.
- Review the graph, result table, and export buttons.
- Use the example table below to compare typical setups.
Example Data Table
| Example | Reference | Span | Rise | Angle | Rise % |
|---|---|---|---|---|---|
| Trainer build | Full | 2.40 m | 0.12 m | 5.71° | 10.00% |
| Sport model | Full | 1.80 m | 0.07 m | 4.45° | 7.78% |
| Scale wing | Half | 0.95 m | 0.06 m | 3.61° | 6.32% |
| Jet anhedral | Full | 2.00 m | -0.05 m | -2.86° | -5.00% |
Understanding Wing Dihedral Angle
Wing dihedral is the upward tilt of a wing from the root. It is measured against a horizontal reference line. A positive angle means the tips sit higher than the root. A negative value is anhedral. Designers use this geometry to influence roll stability, handling feel, and ground clearance.
Why This Measurement Matters
Dihedral affects how an aircraft reacts after a disturbance. More dihedral usually improves lateral self-correction. Too much can slow roll response. Too little can reduce natural stability. Model builders, students, and engineers often check the angle while comparing layouts, adjusting wing mounts, or validating workshop measurements.
Inputs Used in the Calculator
This calculator works with span and rise values. It can use full span or half-span. You can also enter left and right tip rise values. The tool averages both sides when needed. It also solves for unknown rise or required span when the angle is already known.
Useful Output Values
The main result is the dihedral angle in degrees. The page also reports radians, slope ratio, rise percentage, and root-to-tip length. These extra values help with drawing, jig setup, and quick design checks. A small graph shows the wing line, so the geometry is easier to verify visually.
Practical Measuring Tips
Measure from the same reference surface each time. Keep the fuselage level before recording rise. Use the wing centerline as the root reference. Check both tips because builds are not always perfectly symmetric. For workshop use, record units clearly. Mixing inches and millimeters causes fast errors.
Common Design Uses
Common uses include trainers, sailplanes, sport models, and concept studies. Trainers often need noticeable dihedral for forgiving behavior. Aerobatic layouts may use less. Flying wings follow different stability rules. Even when a value comes from drawings, a calculator still confirms shop measurements, repairs, and planned geometry changes during fitting and review.
When to Recheck the Result
Recheck the result after changing span, wing joiner height, or mounting position. Small geometry changes can shift the angle. Recheck again after covering, sanding, or transport damage. A quick recalculation helps maintain accuracy. That makes this tool useful for both early planning and final assembly inspection.
FAQs
1. What is wing dihedral?
Wing dihedral is the upward angle of the wing when viewed from the front. It is measured between the wing and a horizontal reference line through the aircraft center.
2. Why do designers use dihedral?
Dihedral can improve lateral stability. After a roll disturbance, it helps the aircraft return toward level flight. The exact effect depends on the full aircraft design.
3. What is anhedral?
Anhedral is a negative wing angle. The tips sit lower than the root. It is often used where designers want less natural roll stability or different handling behavior.
4. Should I enter full span or half span?
Enter either one, but match the selector first. The calculator converts the value internally. Full span is total tip-to-tip width. Half span is root to one tip.
5. Can I enter different left and right rise values?
Yes. The calculator averages left and right rise when both are entered. It also reports the difference, which helps you spot build asymmetry quickly.
6. Do span and rise need the same unit?
Yes. Use the same length unit for both values. The angle depends on their ratio. Mixed units will create a wrong result immediately.
7. What does the slope ratio show?
The slope ratio compares horizontal half-span to rise. A result of 1:10 means ten units of half-span produce one unit of rise.
8. Can this calculator help with workshop checks?
Yes. It is useful for setup jigs, repairs, final inspection, and drawing checks. You can compare measured rise against the target angle fast.