https://matteocampagna.com/en/registry/equipment/mathematical-bow-model-predictions 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/mathematical-bow-model-predictionsComparisons between model and real bow are few, almost all reported in words or in a graph, and on draw weight they point in different directions. The first, in 1969, sets the calculated draw curve beside that of a commercial recurve: a simple approximation, normalised on the measured curve, follows it very closely up to 6.5 inches of draw, and the full model, calibrated on one measured point at 11 inches, agrees well enough in the author's judgement. The Dutch group that built the classic bow model reports that on a replica of a Mary Rose longbow the predicted draw weight came within 1% of the measured one; on a modern maple and fibreglass recurve, by contrast, it was too high, and the model was brought into line with the measurement by a correction factor on limb stiffness. On a compound too, in 2009, the calculated force-draw curve follows the measured one, but with the limb stiffness chosen so that the peak force matches. On efficiency the picture is clearer: models with an inextensible string predicted more than 90% against the 70 to 85% measured, an analysis from 1981 puts the gap down to the energy left in the limbs and string as the arrow leaves, and on the Dutch recurve, even after the correction, the measured efficiency stayed a few percentage points below the calculated value. The three-link model of the Japanese bow, in 1997, reproduced the pattern of string tension, torsion and compression without matching the values. The half about efficiency holds, because the models put it higher than the measurement; the half about draw weight holds for the longbow, while on the recurve and the compound the model has to be tuned to the real bow. All of this rests on a handful of bows, with no stated sample size.claim:modello-arco-previsioni:revision:2026-06-13:3Sat, 13 Jun 2026 08:00:00 GMT https://matteocampagna.com/en/registry/equipment/mathematical-bow-model-predictionsclaim:modello-arco-previsioni:new_claim:2026-04-18:contestatoSat, 18 Apr 2026 08:00:00 GMT