The opposite of dihedral is anhedral.
Understanding Dihedral and Anhedral
Dihedral and anhedral are terms used primarily in the fields of aeronautics and architecture, describing the angle of wings or surfaces relative to a reference point, often the horizontal.
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Dihedral: This refers to an upward angle from the root to the tip of a wing or surface, creating a V-shape when viewed from the front or rear. Dihedral enhances lateral stability, helping an aircraft return to a level position after a disturbance.
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Anhedral: This is the opposite, describing a downward angle from the root to the tip, forming an inverted V-shape. While anhedral can make an aircraft more maneuverable, it generally reduces stability.
Comparison Table
| Feature | Dihedral | Anhedral |
|---|---|---|
| Angle | Upward from root to tip (V-shape) | Downward from root to tip (inverted V-shape) |
| Effect on Stability | Increases lateral stability | Decreases lateral stability |
| Effect on Maneuverability | Generally reduces maneuverability | Generally increases maneuverability |
Implications of Anhedral
The reference indicates that anhedral is used to reduce the dihedral effect, thereby shifting the aircraft’s roll characteristics to a performance range where it is both stable and maneuverable. This is particularly important in the design of high-performance aircraft.
- Practical Use: While dihedral is common in standard aircraft for stability, anhedral might be preferred in situations where higher maneuverability is needed at the expense of stability, such as in acrobatic planes.
- Design Considerations: The choice between dihedral and anhedral depends on the specific performance requirements of the aircraft or structure. Often, designers use a combination of both in various parts of a structure to achieve specific stability and control characteristics.
Examples
- Dihedral in Aircraft: Many commercial airliners have a slight dihedral for stability.
- Anhedral in Aircraft: Some military fighters may incorporate anhedral to enhance their roll rate and agility.
