Editing Flap (aeronautics) (section)

===Related devices===
* '''[[Leading edge slats]] and [[Leading edge slot|slot]]s''' are mounted on the top of the wings' leading edge and while they may be either fixed or retractable, when deployed they provide a slot or gap under the slat to force air against the top of the wing, which is absent on a Krueger flap. They enhance controllability at low speeds. Leading edge slats allow the wing to fly at a higher angle of attack which decrease takeoff and landing distances.<ref>{{Cite web|url=https://www.flightglobal.com/pdfarchive/view/1921/1921%20-%200845.html|title=fig {{!}} slot opffh {{!}} pbar slot {{!}} 1921 {{!}} 0845 {{!}} Flight Archive|website=www.flightglobal.com|access-date=2019-04-18|archive-date=15 May 2019|archive-url=https://web.archive.org/web/20190515150512/https://www.flightglobal.com/pdfarchive/view/1921/1921%20-%200845.html|url-status=live}}</ref> Other types of flaps may be equipped with one or more slots to increase their effectiveness, a typical setup on many modern airliners. These are known as slotted flaps as described above. Frederick Handley Page experimented with fore and aft slot designs in the 20s and 30s.
* '''[[Spoiler (aeronautics)|Spoilers]]''' are intended to increase drag by "spoiling" the airflow over the wing. A spoiler is much larger than a Gurney flap, and can be retracted. Spoilers are usually installed mid chord on the upper surface of the wing, but may also be installed on the lower surface of the wing as well.
* '''[[Air brake (aircraft)|Air brakes]]''' are used to increase drag, allowing the aircraft to descend at a steep angle or decelerate rapidly.
* '''[[Aileron]]s''' are similar to flaps (and work the same way), but are intended to provide lateral control, rather than to change the lifting characteristics of both wings together, and so operate differentially – when an aileron on one half-wing increases the lift on that half-wing, the opposite aileron does not, and will often work to decrease lift on its half-wing. When ailerons are designed to lower in conjunction with flaps, they are usually called [[flaperon]]s, while those that spoil the airflow (typically placed on the upper surface before the trailing edge) they are called [[spoileron]]s.
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<gallery>
File:ILA 2008 PD 750.JPG|Plain flap at full deflection.
File:Avro Lancaster flap Flickr 4841178432.jpg|Split flap on a World War II bomber
File:A fully extended flap.jpg|Double slotted Fowler flaps extended for landing
File:Undercarriage.b747.arp.jpg|Krueger flaps and triple-slotted trailing-edge flaps of a [[Boeing 747]] extended for landing
File:Kitfox Lite.jpg|Junkers flaps, doubling as [[ailerons]].
</gallery>