Editing Angle of attack (section)

==Very high alpha==
[[File:Su-35 (12509727094).jpg|thumb|Su-27M / [[Su-35]] at high angle of attack]]

{{Further|High Alpha Research Vehicle}}

Some military aircraft are able to achieve controlled flight at very high angles of attack, but at the cost of massive [[induced drag]].  This provides the aircraft with great agility.  A famous example is [[Pugachev's Cobra]]. Although the aircraft experiences high angles of attack throughout the maneuver, the aircraft is not capable of either aerodynamic directional control or maintaining level flight until the maneuver ends. The Cobra is an example of [[Supermaneuverability|supermaneuvering]]<ref>[https://books.google.com/books?id=Ti3lNwAACAAJ Timothy Cowan]</ref><ref>{{Cite web |url=http://apps.dtic.mil/dtic/tr/fulltext/u2/a224126.pdf |title=DTIC |access-date=2022-06-02 |archive-date=2023-03-15 |archive-url=https://web.archive.org/web/20230315051852/http://apps.dtic.mil/dtic/tr/fulltext/u2/a224126.pdf |url-status=dead }}</ref> as the aircraft's wings are well beyond the critical angle of attack for most of the maneuver.

Additional aerodynamic surfaces known as "high-lift devices" including [[Leading edge extension#Leading edge root extensions|leading edge wing root extensions]] allow [[fighter aircraft]] much greater flyable 'true' alpha, up to over 45°, compared to about 20° for aircraft without these devices. This can be helpful at high altitudes where even slight maneuvering may require high angles of attack due to the low density of air in the upper atmosphere as well as at low speed at low altitude where the margin between level flight AoA and stall AoA is reduced. The high AoA capability of the aircraft provides a buffer for the pilot that makes stalling the airplane (which occurs when critical AoA is exceeded) more difficult. However, military aircraft usually do not obtain such high alpha in combat, as it robs the aircraft of speed very quickly due to induced drag, and, in extreme cases, increased frontal area and parasitic drag. Not only do such maneuvers slow the aircraft down, but they cause significant structural stress at high speed. Modern flight control systems tend to limit a fighter's angle of attack to well below its maximum aerodynamic limit.{{citation needed|date=November 2012}}