https://matteocampagna.com/en/registry/equipment/shafts-natural-spin-vanes 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/shafts-natural-spin-vanesIt comes from a single source, and not even from a published measurement. In a 2019 review of how the air affects target archery, the author reports as-yet-unpublished work showing that some arrow types leave the bow already spinning about their own axis, even without vanes. The vanes should therefore be set at an angle that goes with that spin: if they oppose it, the spin first slows down and then reverses. The author writes that he has not yet seen a satisfactory explanation of why this happens, although in his view there is compelling evidence that it is real, and that it looks like a property of certain shafts rather than of the bow. Which shafts, how many revolutions per second and with what effect on the group, the review does not say, and it gives neither data nor method. Without the original work, a mention inside a review is not enough to say the question has been studied: for now it is a report to be checked, not a fletching instruction.claim:aste-rotazione-propria-alette:revision:2026-10-16:2Fri, 16 Oct 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/shafts-natural-spin-vanesclaim:aste-rotazione-propria-alette:new_claim:2026-10-14:non_studiatoWed, 14 Oct 2026 08:00:00 GMT