Types of Aircraft Flaps
An aircraft flap is a high-lift device mounted on the wing-trailing edges of an aircraft where they increase an aircraft wing’s lift. Flaps also produce extra lift when an aircraft is taking off and, when they are extended, increase the curvature of the wing to help the aircraft generate lift even at low speeds. Essentially, aircraft flaps adapt to aid in whatever phase of flight your aircraft is in. Despite them all carrying out relatively similar functions, there are multiple types of aircraft flaps. In this blog, we will discuss the six most common types and explain their unique characteristics.
1. The first type of flaps, plain flaps, are hinged to the rear of the aircraft wing and pivot downward when they are in use. Flaps of this type are limited in the amount of lift they can create because air can lose energy as it moves over the wing. The more pronounced the flap’s extension is, the stronger the airflow and larger the wake. However, the drag created by this wake does allow you to fly the plane to a steeper descent without increasing the airspeed. Plain flaps are not commonly used, mainly because more advanced flaps are now available.
2. Another flap type, split flaps, are also no longer common. These flaps deflect from the wing’s lower surface and produce slightly more lift than plain flaps, but also produce a significant amount of drag. As its name implies, split flaps are split into two parts: an upper surface that remains stationary and a lower surface that moves. Depending on multiple factors, split flaps can either be used to edge the nose of the aircraft up or down.
3. The third type of flaps, slotted flaps, are the most common type of aircraft flap in use today. Slotted flaps look similar to plain flaps but also feature a slot between the flap and wing to decrease the amount of air separation that occurs. This means the airflow remains attached to the flap and provides more lift. In slotted flaps, the higher air below the wings flows upward where the boundary layer is energized. This is a main reason why air flow separation is not as severe as it is in other flap types.
4. Next, Fowler flaps are used on very large jets that require a great deal of lift with limited drag. These flaps extend out on tracks or rails and frequently feature a series of slots to provide added energy to the airflow. They are especially useful during takeoff, where they increase the area of the wing itself. As Fowler flaps extend, they move more and more downard to create more lift and drag. However, this extra drag is useful in some situations like landing.
Beyond the aforementioned four main types of flaps, there are two others: Krueger flaps and Zap flaps. Krueger flaps differ from other types of flaps in that they are found on the aircraft’s leading edge instead of its trailing edge. When these flaps are deployed, the wing’s total chord length is increased, resulting in a new leading edge. Finally, Zap flaps, invented by Edward Zaparka in the 1930s, consist of a leading edge mounted on a track and a mid-chord section that attaches to a pivot via an arm above the track. When the leading edge of the Zap flap moves aft along that track, it forms a triangle that forces the flap downward as the flap’s surface gets narrower and deeper. Zap flaps increase the effective wing area, provide a higher maximum lift, and provide a higher drag capacity.
At NSN Fulfillment, owned and operated by ASAP Semiconductor, we can help you find all types of aircraft flaps in addition to many other parts for the aerospace, civil aviation, and defense industries. Dedicated account managers are always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@nsnfulfillment.com or call us at +1-714-705-4780.
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