https://matteocampagna.com/en/registry/equipment/arrow-flex-drag Changes to this claim in Matteo Campagna's evidence registry: its status, its year-by-year history, revisions of the page. en-gb https://matteocampagna.com/en/registry/equipment/arrow-flex-dragAll the evidence comes from a single Japanese laboratory, which between 2011 and 2017 measured arrow drag in a magnetic suspension wind tunnel and in free flight filmed at high speed. Read together, the studies say that flexing matters because it can decide the regime of the layer of air round the shaft: when it makes that layer turbulent, the drag coefficient rises from about 1.5, the laminar value, to about 2.6, and arrows shot by an expert archer at 57 to 58 metres per second always sit there, between 2.6 and 2.7. At recurve arrow speeds, though, the layer turns turbulent even without flexing: above a Reynolds number of 19,000 the coefficient is around 2.5 with every launch method, compressed air included, and in the only experiment that measures flexing and drag together the flexing amplitude bears no relation to mean drag. At lower speeds flexing is not the only route either, because an arrow that does not flex needs a tilt of just over half a degree. Flexing raises drag where the layer could stay laminar; at competition speeds the regime may already be decided, and on that point the studies disagree.claim:flessione-resistenza:revision:2026-05-08:3Fri, 08 May 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/arrow-flex-dragclaim:flessione-resistenza:new_claim:2026-04-06:contestatoMon, 06 Apr 2026 08:00:00 GMT