Also sometimes referred to a stall fences, these devices tend to delay aerodynamic stall on the outboard portion of the wing by creating an impediment to spanwise flow along the upper wing surface. Several 1960s and '70s swept wing bizjet types used this aerodynamic "tweak" to improve low speed characteristics including the HS125 and Falcon 20. Dassault eliminated the need for them in later wing designs. Hawker/Beech replaced stall fences with vortilons for the HS125 -1000 and 800XP models.
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