Editing STOL (section)

==Design ==
{{Refimprove section|date=July 2022}}
[[File:87 GAF Nomad 22SL Philippine Air Force (7838564596).jpg|thumb|[[GAF Nomad]] of the Philippine Air Force]]
STOL aircraft come in configurations such as [[bush plane]]s, [[autogyro]]s, and [[Conventional landing gear|taildraggers]], and those such as the [[de Havilland Canada Dash-7]] that are designed for use on conventional airstrips. The [[PAC P-750 XSTOL]], the [[Daher Kodiak]], the [[de Havilland Canada DHC-6 Twin Otter]] and the [[Wren 460]] have STOL capability, needing a short ground roll to get airborne, but are capable of a near-zero ground roll when landing.{{Citation needed|date=December 2009}}

[[File:YA2F-1 tilting pipes NAN6-60.jpg|thumb|[[Grumman A-6 Intruder|Grumman YA2F-1 Intruder]] with tilting STOL nozzles<ref>https://ntrs.nasa.gov/api/citations/19810016529/downloads/19810016529.pdf{{Dead link | date=May 2025 | fix-attempted=yes}}</ref>]]

For any plane, the required [[runway]] length is a function of the square of the [[stall speed]] (minimum flying speed), and much design effort is spent on minimizing this number. For [[takeoff]], large [[power-to-weight ratio|power/weight ratio]]s and low [[drag (physics)|drag]] help the plane to accelerate for flight. For landing, the length is minimized by strong [[brake]]s, low landing speed, and [[thrust reverser]]s or [[Spoiler (aeronautics)|spoiler]]s. Overall STOL performance is set by the longer of the runway needed to land or take off.<ref>{{Cite web|date=2015-12-02|title=What's the definition of STOL in aviation?|url=https://www.vikingair.com/twin-otter-series-400/twin-otter-answers/what%E2%80%99s-definition-stol-aviation|access-date=2021-12-20|website=Viking Air Ltd|language=en}}</ref>

[[File:Fieseler Storch (7582553016).jpg|thumb|[[Fieseler Storch]] with German [[Luftwaffe]] markings]]

Of equal importance to runway length is the ability to clear obstacles, such as hills, beyond the runway. For takeoff, large [[power-to-weight ratio|power/weight ratio]]s and low drag increase the rate of climb – required to clear obstacles. For landing, high drag allows the plane to descend steeply without building speed, which would require a longer ground run. Drag is increased by use of [[flap (aircraft)|flap]]s on the wings and by [[Slip (aerodynamic)|forward slip]] (causing the plane to fly somewhat sideways to increase drag).<ref> Denker, John S. "11 Slips, Skids, and Snap Rolls". See How It Flies. Av8n.com. Archived from the original on Nov 11, 2023.</ref>

Typically, a STOL aircraft has a large [[wing]] for its weight. These wings may use [[aerodynamic]] devices like flaps, [[leading edge slot|slots]], [[Leading edge slats|slats]], and [[vortex generator]]s.<ref name="gtri.gatech.edu">{{cite web|url=http://www.gtri.gatech.edu/casestudy/powered-lift|title=Powered Lift: Novel GTRI Design Would Let Commercial Jets Use Smaller Airports While Reducing Noise|publisher=[[Georgia Tech Research Institute]]|access-date=2010-10-28}}</ref> Typically, achieving excellent STOL performance reduces maximum speed, but not [[Payload (air and space craft)|payload]] ability. The payload is critical, because many small, isolated communities rely on STOL aircraft as their only link to the outside world for passengers or cargo; examples include many communities in the [[Canada|Canadian north]] and [[Alaska]].<ref> Time-Life editors 1983, p. 34</ref><ref> "Bush Flying". US Centennial of Flight Commission. Archived from the original on 24 July 2008. Retrieved 14 July 2008.</ref><ref>"Alaska". World Atlas. Retrieved 14 July 2008.</ref>

Most STOL aircraft can [[landing|land]] either on- or off-airport. Typical off-airport landing areas include snow or ice (using skis), fields or gravel riverbanks (often using special fat, low-pressure [[tundra tire]]s), and water (using [[Float (nautical)|float]]s): these areas are often short and obstructed by trees or hills. Wheel skis and amphibious floats combine wheels with [[ski]]s or floats, allowing landing on snow/water.{{Citation needed|date=December 2009}}