https://matteocampagna.com/en/registry/equipment/arrow-two-drag-regimes 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-two-drag-regimesThat the same arrow, at the same speed, can fly with two very different drag levels has been measured several times, but always by the same research group in Tokyo and almost always with arrows fired by compressed air, which do not flex. Between Reynolds numbers of 1.3 and 1.8 times 10 to the fourth, the drag coefficient of an A/C/E arrow splits into two families, about 1.5 to 1.6 with a laminar air layer and about 2.6 with a turbulent one, and the two families stay apart even when the shots are raised to sixty. What decides it is the attitude: four to six tenths of a degree of incidence are enough to turn the flow turbulent, and within a single flight a sensor in the shaft sees the deceleration fall from 0.65 to 0.30 G as the oscillation dies away. That this shifts the point of impact in height is the authors' calculation: about 15 centimetres at 60 metres, worked out from the two drag levels at 60 metres per second. Two findings limit how much it matters to an archer. The arrow shot by an elite archer at 58 metres per second, already above the band at a Reynolds number of 2.0 times 10 to the fourth, gave the turbulent value, 2.65, and the same value, 2.68 and 2.63, turns up with two different vanes; and with a bow, the flexing of the shaft makes the flow turbulent across the whole band when a robot releases with mechanical fingers, while the two values return with a release aid, which barely flexes the shaft. Nobody has yet counted impacts at two heights.claim:resistenza-bistabile-impatto:revision:2026-10-03:3Sat, 03 Oct 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/arrow-two-drag-regimesclaim:resistenza-bistabile-impatto:new_claim:2026-09-30:riportatoWed, 30 Sep 2026 08:00:00 GMT