Fowler flaps are a type of aircraft high-lift device that significantly increases both the wing's lift and drag. They are a more complex type of flap compared to a simple flap, as they not only hinge downwards, but also extend rearward before doing so.
Detailed Explanation
A Fowler flap is characterized by its unique movement which allows it to increase the wing's surface area (chord) and also its curvature (camber). This provides a much greater increase in lift and drag than simpler flap designs.
How Fowler Flaps Work:
- Rearward Extension: Unlike plain or split flaps, a Fowler flap initially slides backward along a track or mechanism.
- Hinging Downward: After extending rearward, the flap then hinges downwards, increasing the wing's camber.
- Increased Chord and Camber: This dual action of rearward movement and downward hinging results in a larger effective wing area (chord) and increased camber, leading to a substantial increase in lift.
- Can be part of upper surface: While similar to split flaps, Fowler flaps can be part of the upper surface of the wing.
- Can be not part of the upper surface: Similar to split flaps, Fowler flaps may not form part of the upper surface of the wing.
Benefits of Fowler Flaps:
- High Lift: The increase in wing area and camber allows aircraft to fly slower during takeoff and landing, which greatly improves safety.
- Increased Drag: While drag can sometimes be a disadvantage, during landing drag from Fowler flaps is used to help slow the aircraft down.
- Improved Control: Fowler flaps give better control at lower speeds.
Comparison with Other Flap Types
| Feature | Fowler Flap | Plain Flap | Split Flap |
|---|---|---|---|
| Movement | Slides rearward, then hinges downward. | Hinges downward. | Hinges downward only from lower surface. |
| Chord Increase | Yes | No | No |
| Camber Increase | Yes | Yes | Yes |
| Surface | Can be part of the upper wing surface, or not | Part of the upper wing surface. | Not part of the upper wing surface. |
| Lift Increase | Very high | Moderate | Moderate |
| Drag Increase | High | Moderate | Moderate |
Practical Insights
- Common Use: Fowler flaps are often found on larger commercial aircraft and cargo aircraft where the need for high lift at slower speeds is critical.
- Complex Systems: Fowler flaps often require a more complex mechanical system compared to simpler flaps, which increases maintenance and weight.
- Multiple Sections: Some Fowler flaps are multi-slotted and have multiple sections that extend sequentially, further enhancing their effectiveness.
In conclusion, Fowler flaps are advanced high-lift devices that increase the wing's surface area and curvature, offering significant lift and drag benefits during takeoff and landing.
