Engineering:STOL

From HandWiki

A short takeoff and landing (STOL) aircraft is a fixed-wing aircraft that can take off and land on runways that are much shorter than the typical ones needed for conventional take-off and landing. STOL-capable aircraft are usually light aircraft (mostly propeller-driven utility aircraft, sporters or motor gliders) with a high lift-to-drag ratio and typically also a high aspect ratio, allowing them to achieve minimum takeoff speed (i.e. liftoff speed or VLOF) much more quickly and thus requiring a shorter accelerating run before taking off (takeoff roll); and perform landing at a lower minimum steady flight speed (VS0) and thus also a shorter decelerating run (rollout).

Gyrocopters, despite being rotary-wing aircraft, need a forward motion to drive air flow past autorotating rotor blades to generate lift and thus still mandate runways (albeit a very short one) for takeoff and landing. They are therefore also considered STOL aircraft, as they cannot perform vertical takeoff and landing like helicopters.

STOL aircraft, including those used in scheduled passenger transport operations, can be operated from STOLport airfields that feature dedicated short runways. They can also operate on improvised airstrips with unpaved runways (e.g., dirt roads or bulldozed grassfield tracks) and/or harsher conditions, such as remote airfields built in high altitude alpine regions, deserts or on snow/ice fields.

Design

GAF Nomad of the Philippine Air Force
Grumman YA2F-1 Intruder with tilting STOL nozzles[1]

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/weight ratios and low drag help the plane to accelerate for flight. For landing, the length is minimized by strong brakes, low landing speed, and thrust reversers or spoilers. Overall STOL performance is set by the longer of the runway needed to land or take off.[2]

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/weight ratios 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 flaps on the wings and by forward slip (causing the plane to fly somewhat sideways to increase drag).[3]

Typically, a STOL aircraft has a large wing for its weight. These wings may use aerodynamic devices like flaps, slots, slats, and vortex generators.[4] Typically, achieving excellent STOL performance reduces maximum speed, but not 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 Canadian north and Alaska.[5][6][7]


In 2025 the Electra prototype aircraft demonstrated take-off in less than 35 mph combining eight electric motors along the front edge of its wings with large blown flaps at the rear edge.[8]

STOL Military Aircraft

  • Lockheed Martin F-35B Lightning II

5th-generation stealth fighter capable of supersonic speeds and short takeoff/vertical landing, often operating from smaller amphibious assault ships.

Historically significant V/STOL aircraft capable of short takeoffs with heavy payloads, or vertical landing.

Large military transport aircraft that can operate from runways as short as 3,500 feet.

Tactical airlifter with outstanding short-takeoff performance from unpaved, soft, or sandy surfaces.

  • General Atomics Mojave

Unmanned, remotely piloted aircraft (drone) with Short Takeoff and Landing capabilities, designed for expeditionary roles.

Kits

Micro Dynamics vortex generators mounted on the wing of a Cessna 182K

A number of aircraft modification companies offer STOL kits for improving short-field performance.

  • Crosswinds STOL of Wasilla, Alaska, sells STOL kits for light aircraft, including leading edge cuffs, tip spill plates, inboard flap extensions and STOL fences. The company offers kits for Piper PA-12, PA-14, PA-18, PA-20 and 22, Bellanca Champion Model 7 series, Cessna 170B, 180 and 185.[9]
  • Horton, Inc, of Wellington, Kansas, offers STOL kits under the brand name Horton STOL-Craft, emphasizing that the modifications increase safety by allowing forced landings to occur at lower speeds and thus improve survivability. The Horton modifications include a drooped leading edge cuff, conical cambered wingtips, control surface gap seals and wing fences. The company says: "On an average you can expect to get a 4-7 knot reduction in stall speeds. Flying at these lower stall speeds you can reduce the take-off and landing distances by 10%". Horton STOL kits are available for several Cessna and Piper PA-28 models.[10][11][12]
  • Micro AeroDynamics markets vortex generator modification kits for "STOL benefits". The Micro kits are small vortex generators that are glued to the wing leading edge, as well as the underside of the elevator and on the fin. Kits are available for a large number of light aircraft types.[13]
  • Sierra Industries sells Robertson STOL kits, marketed under the name R/STOL, incorporate a drooped leading edge cuff, wing fences, drooping ailerons and an automatic trim system. The company says that installation "allows 15 to 25 MPH slower approaches and requires up to 40% less runway distance". R/STOL kits are available for various Cessna models.[14][15][16]
  • Stolairus Aviation of Kelowna, British Columbia, has developed STOL Kits for the de Havilland Canada DHC-2 Beaver and de Havilland Canada DHC-3 Otter to increase lift and reduce stall speeds. The DHC-2 Beaver STOL Kit includes a contoured leading edge, flap-gap seals, wing fences and drooped wingtips. The DHC-3 Otter STOL Kit includes a contoured leading edge and drooped wingtips.[17]

STOLport

This section is an excerpt from STOLport[ edit ]

CESTOL

Cruise-efficient short takeoff and landing (CESTOL) have very short runway requirements and cruise speeds greater than Mach 0.8.[4][18][19]

Definitions

Many definitions of STOL have been used over time and for regulatory and military purposes.[20] These include:

(DOD/NATO) The ability of an aircraft to clear a 50-foot (15 meters) obstacle within 1,500 feet (450 meters) of commencing takeoff or in landing, to stop within 1,500 feet (450 meters) after passing over a 50-foot (15 meters) obstacle.
the ability of aircraft to take off and clear a 50-foot obstruction in a distance of 1,500 feet from beginning the takeoff run. It must also be able to stop within 1,500 feet after crossing a 50-foot obstacle on landing.

{{quote

an aircraft with a certified performance capability to execute approaches along a glideslope of 6 degrees or steeper and to execute missed approaches at a climb gradient sufficient to clear a 15:1 missed approach surface at sea level... A STOL runway is one which is specifically designated and marked for STOL aircraft operations, and designed and maintained to specified standards.
Heavier-than-air craft that cannot take off and land vertically, but can operate within areas substantially more confined than those normally required by aircraft of the same size. Derived from short takeoff and landing aircraft.
heavier-than-air craft, capable of rising from and descending to the ground with only a short length of runway, but incapable of doing so vertically. The precise definition of an STOL aircraft has not been universally agreed upon. However, it has been tentatively defined as an aircraft that upon taking off needs only 1,000 ft (305 m) of runway to clear a 50-ft (15-m) obstacle at the end of that distance and upon landing can clear the same obstacle and then land within 1,000 ft.
The STOL mode of flight is one during which an airplane taking off or landing is operated at climb-out and approach speeds lower than the conventionally accepted margins of airspeed above the power-off stalling speed of the airplane.

Some manufacturers market their products as STOL without specifying that the aircraft meets an accepted functional definition.[21]

See also

References

  1. ↑ Snell, W.C.; Ordonez, G. W.. "Axisymmetric and Non-Axisymmetric Exhaust Jet Induced-Effects on a Vistol Vehicle Design". Grumman Aerospace Corporation. https://ntrs.nasa.gov/api/citations/19810016529/downloads/19810016529.pdf. 
  2. ↑ "What's the definition of STOL in aviation?" (in en). 2015-12-02. https://www.vikingair.com/twin-otter-series-400/twin-otter-answers/what%E2%80%99s-definition-stol-aviation. 
  3. ↑ Denker, John S. "11 Slips, Skids, and Snap Rolls". See How It Flies. Av8n.com. Archived from the original on Nov 11, 2023.
  4. ↑ 4.0 4.1 "Powered Lift: Novel GTRI Design Would Let Commercial Jets Use Smaller Airports While Reducing Noise". Georgia Tech Research Institute. http://www.gtri.gatech.edu/casestudy/powered-lift. 
  5. ↑ Time-Life editors 1983, p. 34
  6. ↑ "Bush Flying". US Centennial of Flight Commission. Archived from the original on 24 July 2008. Retrieved 14 July 2008.
  7. ↑ "Alaska". World Atlas. Retrieved 14 July 2008.
  8. ↑ Ridden, Paul (2025-08-13). "Hybrid-electric short takeoff and landing plane shows promise" (in en-US). https://newatlas.com/aircraft/electra-el2-hybrid-electric-stol-public-demo/. 
  9. ↑ Crosswinds S.T.O.L. Inc. (2011). "Crosswinds STOL Inc.". http://www.crosswindsstol.com. 
  10. ↑ Horton, Inc.. "Description of the Horton STOL Kit". http://www.hortonstackdoor.com/stolcraft_description.htm. 
  11. ↑ Horton, Inc.. "Frequently Asked Questions About the Horton STOL Kit". http://www.hortonstackdoor.com/stolcraft_faq.htm. 
  12. ↑ Horton, Inc.. "Horton STOL Kit Pricing". http://www.hortonstackdoor.com/stolcraft_pricing.htm. 
  13. ↑ Micro AeroDynamics Inc (2009). "Micro Vortex Generators for Single and Twin Engine Aircraft". http://www.microaero.com/. 
  14. ↑ Sierra Industries (2007). "Sierra R/STOL High Lift Systems for Piston Engine Aircraft". http://www.sijet.com/sitemap_rstol.aspx. 
  15. ↑ Sierra Industries (2007). "Sierra R/STOL Performance Comparison Charts". http://www.sijet.com/SierraRSTOL_performanceComparison.aspx. 
  16. ↑ Sierra Industries (2007). "Modifications - Sierra R/STOL High Lift Systems for Piston Engine Aircraft". http://www.sijet.com/d563beaf-cce6-4770-9feb-e4bf0c42bc76.aspx. 
  17. ↑ "DHC-2 Beaver." Stolairus Retrieved: February 2, 2012.
  18. ↑ Hange, Craig E (2005-04-25). "Short Field Take-Off and Landing Performance as an Enabling Technology for a Greener, More Efficient Airspace System". Ames Research Center, NASA. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090036801_2009036530.pdf. 
  19. ↑ "Novel Design". Aerospace Manufacturing and Design. May 2011. http://www.onlineamd.com/amd-0511-novel-design-reducing-noise.aspx. 
  20. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Columbia
  21. ↑ Fisher Flying Products. "Horizon 1". http://www.fisherflying.com/index.php?option=com_content&view=article&id=40&Itemid=22. 
External video
STOL Ultralight taking off and landing



Retrieved from "https://handwiki.org/wiki/index.php?title=Engineering:STOL&oldid=4340583"