An arrow-launching machine at 70 m picks out defective arrows
4 studies
The summary today
The machine is consistent enough to separate the arrow from the archer, but the test with genuinely defective arrows is a single, small one. In 2020 a 114 kg recurve machine shot six arrows at 70 m on a day with little wind: the four sound ones stayed within a circle of twice the standard deviation, the two defective ones landed outside it, and each always on the same side, the one with a missing vane low and the other to the right, whether or not the clicker was used as the release signal. In 2025 a study of 59 arrows of the same model, shot at 70 m indoors by a machine, measures its repeatability: the same arrow shot thirty times lands a median 1.3 cm from the group centre, with 95% of impacts within 3.5 cm, and mass and mean spine account for 46.7% of the arrows' vertical position, while mean spine and the variation of spine around the shaft account for 18.6% of the horizontal one. There, though, the arrows are not defective, they are good arrows that differ slightly. The comparison shows why the machine is useful: at 55 m an archer spreads 107-108 mm vertically against 34 mm for a robot and 9 mm for its improved version. What nobody has checked is whether the arrows the machine rejects are the ones that lose points in competition: that is why the status is "Reported".
Also phrased as: "testing arrows with a shooting machine"; "discarding the arrow that leaves the group"; "arrow selection with a robot"; "an arrow that always goes to the same side"
In practice
Archers are advised to number their arrows, shoot them several times and discard the one that always lands outside the group, perhaps after trying a different nock rotation; those who can use a machine to take the archer out of the equation.
Evidence
-
2012
Context Equipment tests Published later
A proposed system for measuring the point of impact in the industrial testing of arrows: shooting machine at about 39 m, typical speed about 275 km/h, each arrow shot three times with the nock rotated by 120°, quality read from the spread of the three impacts with an index (arrow no. 2 has the lowest value, 0.2707, unit not given). It does not say how many arrows, or which were defective; regional journal.
Measuring System for Impact Point of Arrow using Mamdani Fuzzy Inference System · Jung-Won Yu, Han-Soo Lee, Yeong-Sang Jeong, Sung-Shin Kim
-
2020
For Equipment tests Published later
A 114 kg machine with a 40 lb recurve, six arrows shot at 70 m on a day with little wind, two of them defective: the four normal ones stayed within two standard deviations, the two defective ones outside, and always in the same direction (the one with a missing vane low, the other to the right), with and without the clicker as the release signal.
Development of an Archery Robot for the Selection of Arrows · Masashi Ohara, Naoki Kawasaki, Jun Nakahama, Yogo Takada, Hitoshi Watanabe
-
2022
Context Equipment tests Published later
Shots at 55 m indoors analysed with cameras at 3,000 frames per second: one archer, with 36 arrows, has a launch speed of 59.67 ± 0.34 and 59.21 ± 0.40 m/s and a vertical spread of 107 and 108 mm; the robot 58.55 ± 0.13 m/s and 34 mm; the improved robot 51.96 ± 0.019 m/s and 9 mm. With different arrows for archer and robot, and the air conditioning switched off to keep the air as still as possible.
Automatic image analysis of an archery arrow in free flight using high-speed video cameras · Riku Murakami, Hiroya Mamori, Takeshi Miyazaki, Naoya Takahashi
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2025
For Equipment tests Published later
59 Easton X10 arrows of the same model, characterised on a test bench and shot at 70 m indoors by a machine over five sessions: the same arrow shot 30 times lands a median 1.3 cm from the group centre (95% CI 0.8-2.1), with 95% of impacts within 3.5 cm, and each arrow varies by about 2 cm between sessions. Mass and mean spine account for 46.7% of the vertical position, mean spine and the amplitude of its variation around the shaft for 18.6% of the horizontal one: the machine separates the arrows, but none of them is defective.
Improving the arrow selection process in archery: the stiffness variation pattern matters · A. Kuch, P. Laguillaumie, F. Durand, J.-F. Debril, T. Monnet
Status history
- 2012 Not studied Testing arrows with a machine appears as a proposed method: each arrow is shot three times at about 39 m with the nock rotated by 120° and its spread is measured. The paper does not say how many arrows it tested or which were defective, so it does not yet show that the machine picks them out.
- 2020 Reported The first test with defective arrows: a 114 kg machine shoots six arrows at 70 m on a day with little wind, the four sound ones stay within two standard deviations and the two defective ones land outside, always on the same side, the one with a missing vane low and the other to the right. A test on equipment counts as direct evidence, but it is a single one, on six arrows: reported.
- 2022 Reported The comparison between an archer and a robot at 55 m shows why the machine is useful: the archer spreads 107-108 mm vertically against 34 mm for the robot and 9 mm for the improved version, and the archer's launch speed varies by 0.34-0.40 m/s against 0.13 and 0.019. A defect that shifts the impact by a few centimetres is lost, in the archer's hands, in the noise of the shot. It is context and the status does not move.
- 2025 Reported A study of 59 arrows of the same model quantifies repeatability at 70 m: the same arrow shot thirty times lands a median 1.3 cm from the group centre, with 95% of impacts within 3.5 cm, and mass and mean spine account for almost half of the arrows' vertical position. The machine tells apart good arrows that differ slightly, but they are not defective arrows, and nobody has checked whether the rejected arrows are the ones that lose points in competition: it stays reported.
Related
Related articles
- Does better equipment put points on the scorecard? What shooting machines and archers showShooting machines, archers handed a bow that is not theirs and blind ratings: what the studies say about how much equipment counts towards your score.
- Choosing and matching competition arrowsWhich spine to choose and how alike the arrows in a dozen are: charts, weight, the stiff side of the shaft, straightness and nocks, as studies measure them.
- When to retire an arrow, and why a shaft snaps on releaseWhich knocks damage an arrow, why a shaft snaps on release, and what the tests say about straightness, wear and defective arrows.
Research lines
Cite
Campagna, M. (2026). An arrow-launching machine at 70 m picks out defective arrows (Version 2). In Evidence Registry. Retrieved 16 October 2026, from https://matteocampagna.com/en/registry/equipment/shooting-machine-defective-arrows
@misc{campagna2026_macchinafreccedifettose,
author = {Campagna, Matteo},
title = {An arrow-launching machine at 70 m picks out defective arrows},
year = {2026},
howpublished = {Evidence Registry, matteocampagna.com},
url = {https://matteocampagna.com/en/registry/equipment/shooting-machine-defective-arrows},
note = {Version 2; accessed 2026-10-16}
}
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