Flight Controls

when the flap is lowered, a duct forms between the flap well Fowler flaps are a type of slotted flap. This flap design not in the wing and the leading edge of the flap. When the slotted only changes the camber of the wing, it also increases the flap is lowered, high energy air from the lower surface is wing area. Instead of rotating down on a hinge, it slides ducted to the flap’s upper surface. The high energy air from backwards on tracks. In the first portion of its extension, it the slot accelerates the upper surface boundary layer and increases the drag very little, but increases the lift a great delays airflow separation, providing a higher C . Thus, the deal as it increases both the area and camber. Pilots should L slotted flap produces much greater increases in maximum be aware that flap extension may cause a nose-up or down coefficient of lift (C ) than the plain or split flap. While pitching moment, depending on the type of aircraft, which L-MAX there are many types of slotted flaps, large aircraft often the pilot will need to compensate for, usually with a trim have double- and even triple-slotted flaps. These allow the adjustment. As the extension continues, the flap deflects maximum increase in drag without the airflow over the flaps downward. During the last portion of its travel, the flap separating and destroying the lift they produce. increases the drag with little additional increase in lift. Leading Edge Devices Basic section High-lift devices also can be applied to the leading edge of the airfoil. The most common types are fixed slots, movable slats, leading edge flaps, and cuffs. [Figure 6-18] Fixed slots direct airflow to the upper wing surface and delay airflow separation at higher angles of attack. The slot does not Plain flap Fixed slot Split flap Movable slot Slotted flap Leading edge flap Fowler flap Leading edge cuff Slotted Fowler flap Figure 6-17. Five common types of flaps. Figure 6-18. Leading edge high lift devices. 6-9